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Background: Tear production increases ocular surface health and improves visual clarity. Which facilitates the physical activity comfortably. Different dosages of glucose intake had a significantly varying impact on tear production in euglycemic, initially decreasing followed by an increase. Objective: to compare the effect of 0.5% and 1% glucose intake on tear production in euglycemic. Methodology: A quasi-experimental study was conducted with n=200 participants at Irfan Eye Care Hospital Peshawar, from September 2022 to May 2023. The participants were euglycemic without any ocular and systemic pathology and determined its effect on tear production. The participants were divided into two groups equally for 0.5% and 1% glucose intake. Tear production was measured at baseline, after 60 minutes, 90 minutes, 120 minutes, and 150 minutes with the Schirmer test. Results: There was a significant reduction of tear production from baseline to 120 minutes (p

Objective Animals Studied Procedures Results Conclusions To evaluate the effects of topical application of 0.5% tropicamide and 1% atropine on pupil diameter (PD), intraocular pressure (IOP), and tear production (TP) in healthy pet rabbits.Ten healthy client‐owned rabbits.A prospective, randomized, blinded, crossover study was conducted. Each animal received one drop of 0.5% tropicamide or 1% atropine in a randomly selected eye. PD, IOP, and TP were evaluated before drug instillation and at 0.25 h, 0.5 h, 0.75 h, 1 h, 2 h, 4 h, 6 h, 8 h, 10 h, 12 h, 24 h, 36 h, 48 h, 60 h, and 72 h post‐instillation. Data were analyzed using a paired two‐sample repeated measures T‐test with Bonferroni correction.In both tropicamide and atropine treated eyes, the mean PD significantly increased from 15 min until 12 h after treatment with a maximum PD at 45 min (+2.7 mm and + 2.4 mm respectively). Following tropicamide and atropine instillation, IOP increased significantly in treated eyes at 45 min (+2.9 mmHg) and 15 min (+5.2 mmHg) respectively, compared to untreated eyes. No significant effects were found on TP, in both tropicamide and atropine treated eyes at any time. No effects were observed in the untreated eyes on any of the parameters evaluated for both drugs.Topical treatment with 0.5% tropicamide and 1% atropine induced mydriasis in healthy pet rabbits and could be considered as effective options when mydriatic/cycloplegic drugs are required. [ABSTRACT FROM AUTHOR]

This study aimed to compare the effect of intranasal (IN) and intramuscular (IM) administration of butorphanol and zolazepam‐tiletamine (ZT) combination on intraocular pressure (IOP) and tear secretion (TS) in rabbits. Fourteen healthy male New Zealand White rabbits weighing 3.05 ± 0.72 kg, aged between 1 and 2 years old, were included in the study. Animals randomly received 0.5 mg/kg butorphanol and 15 mg/kg ZT combination either with IN or IM administration. IOP and TS were measured at baseline (T0), and followed by 5, 15, 30, 45, and 60 min after drug administration. The sedation variables, the time to onset of sedation, duration of sedation, and sedation scores were also recorded. The route of administration for the butorphanol and ZT combination had no significant effect on the mean IOP (p =.301) and TS (p =.445). Furthermore, there were no significant changes observed in the IOP (p =.472) and TS (p =.348) over time. The time to onset of sedation was earlier in the IN group (4.57 ± 0.79 min) than in the IM group (5.86 ± 0.9 min; p =.0004). The duration of sedation was significantly longer for IM (57.43 ± 3.41 min) compared with IN (45.0 ± 1.91 min; p <.0001). No significant difference in the sedation score was observed between groups at all time points. In conclusion, both IN and IM administration of the butorphanol and ZT combination in rabbits had similar effects on IOP and TS. [ABSTRACT FROM AUTHOR]

The aim of the study is to assess the lacrimal gland tear production, using the Schirmer Tear Test (STT), in healthy sheep under general anesthesia and to explore the effects of applying 1% hyaluronic acid ophthalmic gel during general anesthesia. While STT values during anesthesia have been well documented in small animals such as cats and dogs, there seems to be a lack of information available for ruminants like sheep. This gap in the literature highlights the need for further research and exploration into tear production in sheep under anesthesia. The experimental research conducted on twelve adults female sheep provided valuable insights into tear production under anesthesia. By assessing tear production at various key time points the study was able to capture the changes in tear production throughout anesthesia and revealed a significant decrease in Schirmer Tear Test values in all sheep, following general anesthesia. The results showed that closing and taping the eye yielded determined better outcomes compared to administering a 1% lubricant ophthalmic gel. This finding suggests that eye care during anesthesia can impact tear production in sheep. [ABSTRACT FROM AUTHOR]

Purpose: to study the effect of various methods of intraoperative keratoprotection on morphological and functional state of ocularsurface system (OSS) in early period after phacoemulsification (PE) in senile cataract (SC). Patients and methods. 240 patients (240 eyes) who applied for surgical treatment of SC. Age: 65 ± 4 years. 109 men, 131 women. All patients were divided into three observation groups according to the method of intraoperative keratoprotection: 1st group — 60 patients, corneal irrigation with balanced solution; 2nd group — 60 patients, ophthalmic viscosurgical device was applied to the cornea; 3rd group: 3a subgroup — 60 patients, soft contact lens (SCL) was applied to the cornea; subgroup 3b — 60 patients, SCL impregnated with riboflavin solution was applied to the cornea. In addition to the standard ophthalmological examination, Schirmer I test, OCT-scanning were performed, and tear breakup time (TBUT) was determined. Results. Operations were performed without complications. On the 1st day after the operation, the parameters of the Schirmer I test were higher in the eyes of 1st and 2nd groups. On the 5th day after the operation, tear production decreased sharply in all eyes. On the 10th day, an increase in tear production was observed in all groups, the maximum increase — in 3b subgroup. On the 1st day after the operation, TBUT decreased in all examined eyes. The largest significant TBUT decrease was noted in 1st group, the smallest — in 3b subgroup. On 1st day, corneal epithelial thickness (CET) decreased in all eyes, the maximum decrease was detected in 1st group. On the 5th day, CET continued to decrease in all eyes, the minimum decrease occurred in the 3b subgroup. On the 10th day — a decrease in CET in all groups with minimal significant dynamics in 3b subgroup. Conclusion. The study showed that the state of OSS in the early period after PE in SC depends on the method of intraoperative keratoprotection. The most optimal method of intraoperative protection of corneal epithelium and prevention of negative morphological and functional state of OSS after PE in SC is using of SCL impregnated with riboflavin.

Background: We evaluate the relationship between corneal nerve structure and function in a veteran population. Methods: 83 veterans (mean age: 55 ± 5 years) seen at the Miami Veterans Affairs (VA) eye clinic were included in this study. Each individual filled out questionnaires to evaluate ocular symptoms (5-Item Dry Eye Questionnaire, DEQ5; Ocular Surface Disease Index, OSDI) and ocular pain (Numerical Rating Scale, NRS; Neuropathic Pain Symptom Inventory modified for the Eye, NPSI-Eye). The individuals also underwent an ocular surface examination that captured functional nerve tests including corneal sensation, corneal staining, and the Schirmer test for tear production. Corneal sub-basal nerve analysis was conducted using in vivo confocal microscopy (IVCM) images with corneal nerve density, length, area, width, and fractal dimension captured. IVCM and functional corneal metrics from the right eye were examined using correlational and linear regression analysis. Results: Most corneal structural metrics were not related to functional metrics, except for weak correlations between various IVCM metrics and tear production. In addition, corneal nerve fiber area was positively related to corneal sensation (r = 0.3, p = 0.01). On linear regression analyses, only the corneal fractal dimension remained significantly related to tear production (β = −0.26, p = 0.02) and only the corneal nerve fiber area remained significantly related to corneal sensation (β = 0.3, p = 0.01). Conclusions: Most corneal nerve structural metrics did not relate to functional metrics in our veteran population, apart from a few weak correlations between structural metrics and tear production. This suggests that using corneal nerve anatomy alone may be insufficient for predicting corneal function. [ABSTRACT FROM AUTHOR]

Abstract Background We aimed to check the efficacy of Emustil (oil in water emulsion) drops on tear film index and ocular surface dynamics in dry environments through protection and relief treatment modalities. Methods The subjects were exposed to a dry environment using a Controlled Environment Chamber (CEC) where the relative humidity (RH) was 5% and the temperature was 21 °C and screened for ocular symptoms, tear osmolarity, ocular surface temperature (OST) and tear production using ocular Surface Disease Index questionnaire (OSDI), OcuSense TearLab Osmometer, FLIR System ThermaCAM P620 and Schirmer strips/phenol red test respectively. Tear production was calculated by the Tear Function Index test (TFI). Results The mean tear film osmolarity decreased significantly from 296.8 mOsm/l at 40% RH to 291 mOsm/l at 5%. (p = 0.01). Instillation of Emustil resulted in a significant increase in tear osmolarity in the relief method compared with osmolarity seen at 5% RH when no drop was used. The mean PRT value decreased from 26 ± 9 in normal conditions (40% RH) to 22 ± 4 mm in dry conditions (5% RH). Emustil drops did not induce any significant change in tear production in the PRT test. No significant change was found in OST following exposure to 5% RH. OST did not show a statistically significant change with the emulsion when used for relief (p > 0.05). The mean score of ocular discomfort observed was 70 at 5% RH. Still, the instillation of the oil-in-water emulsion (Emustil) resulted in a noticeable decrease in visual discomfort to 37 (p = 0.00) in protection and 59 in relief (p = 0.05). Emustil drops substantially improved tear film parameters under a desiccating environment, however, tear film parameters respond differently to the management modalities. In the protection method, tear film osmolarity was protected against a dry environment, while in the relief mode, tear production was improved. Conclusion CEC allows for a thorough evaluation of tear film parameters and dry eye treatment protocols in labs, providing greater confidence when applying them to patients. In addition, our study showed that Emustil not only provides protection and relief for dry eyes but also helps to maintain ocular homeostasis in desiccating environments. This indicates a promising potential for improving dry eye treatment protocols.

Various ophthalmic disorders (conjunctivitis, corneal wounds, keratitis) have been reported in donkeys. There are no studies on the effect of medetomidine or tramadol on Schirmer tear test (STT) readings in donkeys. This prospective study investigated changes in STT readings in 24 clinically healthy donkeys (Equus asinus) (14 geldings and 10 mares) treated with commonly used doses of medetomidine hydrochloride and tramadol hydrochloride as mono- or combined therapy. Analgesia, sedation, ataxia, and STT readings were measured before treatment (baseline) and at different periods after administration (5–120 min) of the specific drug in each group. Tramadol monotherapy induced a mild analgesic effect (score 1) at 10 min post-administration. All treated donkeys exhibited mild to moderate ataxia. Medetomidine alone or in combination with tramadol induced a significant decrease (P

Purpose: At present, drug treatments are composing the majority of dry eye therapies. However, considering the side effects of drugs, there has been increasing interest in novel non-drug treatment options, and these new treatments have been researching ways of tear production. Therefore, we aimed to investigate the role of chewing gum on tear-meniscus parameters and blinking rate with objective and quantitative methods. Methods: Sixty eyes of 30 healthy volunteers' tear-meniscus height (TMH), tear-meniscus depth (TMD), and tear-meniscus area (TMA) were acquired with anterior segment-optical coherence tomography. Tear-meniscus measurements were performed before and during chewing gum; at 15 and 30 min. Blinking rates were also recorded both before and during chewing gum for 5 min. Results: TMH, TMD, and TMA values at 15 and 30 min of chewing gum were significantly higher than those values before chewing gum (p<0.001). TMH, TMD, and TMA values at 15 min of chewing gum were similar to those values at 30 min of chewing gum (p>0.05). Blinking rate during chewing gum was significantly higher than that value before chewing gum (p<0.001). Conclusion: To the best of our knowledge, this was the first study demonstrating that chewing gum increased tear-meniscus parameters and blinking rate at acute phase of chewing with objective, quantitative, and non-invasive methods. Chewing gum is cheap, sustainable, and easy to reach. In addition, it is not a drug, and there is no risk of drug-related side effects. According to our outcomes, we thought that chewing gum might improve dry eye-related complaints by increasing tear production and blinking rate. [ABSTRACT FROM AUTHOR]

Simple Summary: Normal values of tear production (STT) and intraocular pressure (IOP) are important values resulting from ophthalmic examinations in animals, but so far there are no data from conscious red deer. The establishment of reference value ranges specific to conscious animals may be useful to institutions in settings where chemical immobilization is not necessary for the examination of the species. A total of 60 red deer were examined in this study. Both eyes of all red deer underwent a complete ophthalmic examination, including evaluation of tear production with the Schirmer tear test and IOP readings. The mean ± standard deviation of STT values were 18.35 ± 4.54 mm/30 s in the right eye and 17.87 ± 4.12 mm/30 s in the left; for both eyes, 18.11 ± 4.33 mm/30 s, with a reference range of 17.33–18.89 mm/30 s. IOP was as follows: 26.96 ± 4.42 mmHg in the right eye and 26.67 ± 3.80 mmHg in the left; for both eyes, 26.81 ± 4.11 mmHg, with a reference range of 26.07–27.55 mm/30 s. No statistically significant differences were found between the right and left eye in terms of IOP and STT values. This study provides the normal range for STT and IOP in healthy red deer. It demonstrates that STT is a practical method for determining tear production, and rebound tonometry is a practical method for evaluating IOP in ophthalmic examinations of deer. Normal values of tear production (STT) and intraocular pressure (IOP) have not been reported in conscious red deer to date. The objective was to determine the normal range of STT and IOP in clinically healthy, conscious red deer (Cervus elaphus) by utilizing a chute restraint. A total of 60 red deer were examined in this study. Both eyes of all red deer underwent a complete ophthalmic examination, including evaluation of tear production with the Schirmer tear test (STT) and assessment of intraocular pressure (IOP) with rebound tonometry, employing the TonoVet® device. The mean ± standard deviation of STT values were 18.35 ± 4.54 mm/30 s in the right eye and 17.87 ± 4.12 mm/30 s in the left; for both eyes, 18.11 ± 4.33 mm/30 s, with a reference range of 17.33–18.89 mm/30 s. IOP was as follows: 26.96 ± 4.42 mmHg in the right eye and 26.67 ± 3.80 mmHg in the left; for both eyes, it was 26.81 ± 4.11 mmHg, with a reference range of 26.07–27.55 mm/30 s. No statistically significant differences were observed between the IOP and STT values of the right and left eyes. This study provides a reference range for the STT and IOP in healthy red deer, showing that STT determination of tear production, and rebound tonometry to evaluate the IOP methods, are practical methods for ophthalmic examination in deer. [ABSTRACT FROM AUTHOR]

Various ophthalmic disorders (conjunctivitis, corneal wounds, keratitis) have been reported in donkeys. There are no studies on the effect of medetomidine or tramadol on Schirmer tear test (STT) readings in donkeys. This prospective study investigated changes in STT readings in 24 clinically healthy donkeys (Equus asinus) (14 geldings and 10 mares) treated with commonly used doses of medetomidine hydrochloride and tramadol hydrochloride as mono- or combined therapy. Analgesia, sedation, ataxia, and STT readings were measured before treatment (baseline) and at different periods after administration (5-120 min) of the specific drug in each group. Tramadol monotherapy induced a mild analgesic effect (score 1) at 10 min post-administration. All treated donkeys exhibited mild to moderate ataxia. Medetomidine alone or in combination with tramadol induced a significant decrease (P<0.05) in the STT readings in both right and left eyes at 5, 15, 30, and 60 min relative to baseline, and the lowest values were observed 60 min after drug administration in both groups. Intravenous administration of medetomidine alone or in combination with tramadol induced a significant reduction in STT readings in clinically healthy donkeys. Therefore, in donkeys, the ocular surface treated with these sedatives should be carefully examined and adequately covered by an artificial tear solution or ophthalmic gel. [ABSTRACT FROM AUTHOR]

Objective: Dry eye disease (DED) is a worldwide source of ocular discomfort. This first-in-human phase 2 clinical study determined the efficacy of treating signs and symptoms of DED using an ophthalmic solution of synthesized mimetic of human collagen (ST-100). Design: This double-masked, randomized, study compared high (60 μg/mL) and low (22 μg/mL) dose ST-100 to vehicle utilizing the Ora, Inc. Controlled Adverse Environment (CAE) during a 28-day period. Participants: Participants included males and females ≥ 18 years of age with signs and symptoms of DED for ≥ 6 months that worsened during CAE exposure who were not taking any topical prescription therapeutic. Intervention: Participants applied ST-100 or vehicle placebo topically to both corneas (1 drop) twice daily via a blow-fill-sealed preservative-free container. Main Outcome Measures: The prespecified primary efficacy sign end point was mean change from baseline (CFB) in total corneal fluorescein staining, and the primary symptom end point was mean CFB in ocular discomfort. A secondary prespecified efficacy end point was CFB in unanesthetized Schirmer’s test for tear film production. Results: Of 160 subjects in the intent-to-treat population (112 female, 48 male, median age 64), 146 completed the study. Total corneal fluorescein staining CFB improved for high-dose ST-100, with superiority over vehicle when both eyes were considered together (2-sample t test: P = 0.0394). High-dose ST-100 was superior to vehicle in Schirmer’s CFB for the study eye (least squares mean difference [confidence interval] = 2.3 [0.6, 4.0], P = 0.0094). For study eyes, the proportion of Schirmer’s test responders (CFB ≥ 10 mm, Schirmer’s responder rate) was 12.2% for high-dose ST-100 versus 0.0% for vehicle (P = 0.0266). The CFB for ocular discomfort score improved in study eyes for high- and low-dose ST-100 (paired t test, P = 0.0133, P = 0.0151, respectively) but without superiority over vehicle (ANCOVA: P = 0.5696, P = 0.8968, respectively). ST-100 Schirmer’s responders also demonstrated total elimination of worsening of corneal fluorescein stain during the stress of CAE sessions. Conclusions: ST-100 significantly improved tear production and related outcomes in DED and was well-tolerated in reducing symptoms. Financial Disclosure(s): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Background: Herpetic stromal keratitis (HSK) is an immunomodulatory disease that develops as a result of herpes simplex virus (HSV)1 or HSV2 reactivation. HSK is the most common form (20-50%) of recurrent herpetic keratitis (HK) that most commonly results in significantly reduced vision. It is well known that changes in biological compound levels in tear fluid can be indicative of the state of the ocular surface and determine whether ocular surface pathology is present, and, therefore, can be used as diagnostic markers of pathological changes in the ocular surface. Lactoferrin (LF) is one of these compounds and has been proven to have innate antibacterial, antifungal, antiviral, antiparasite, anti-inflammatory, immunomodulatory, antioxidative and other properties. Purpose: To determine tear Lf concentration in patients with recurrent acute HSK, its effect on functional characteristics of the ocular surface, and the therapeutic effect of Lacto eyedrops in the comprehensive treatment for this disorder. Material and Methods: The study was conducted at the site of Corneal Pathology Department and Immunology Laboratory of the Institute in January to December 2021. Seventeen patients (17 affected eyes and 17 fellow eyes) with recurrent acute HSK were included in the study. Mean patient age plus or minus standard deviation (SD) was 48.7 ± 16.0 years. The ophthalmological examination included biomicroscopy of the bulbar conjunctiva and cornea, fluorescein test, determination of corneal sensation and basal tear production (Schirmer’s II test), and microbiological examination of the conjunctiva. Tear Lf concentration was determined by a human Lf enzyme-linked immunosorbent assay (ELISA) kit (Elabscience Biotechnology, Inc., Wuhan, China). The results were photometrically measured at 450 nm with an ELISA reader (Stat Fax 2100, Awareness Technology Inc, Palm City, FL). Lacto eyedrops were administered two times a day for 30 days. Tear Lf concentrations were determined at baseline and at day 30. Results: Mean tear LF concentration plus or minus SD in eyes of patients with recurrent HSK was 1.21 ± 0.52 g/l, with no significant difference between the affected eye and fellow eye. However, a subnormal tear LF concentration was more common in the affected eye than in the fellow eye (χ2 = 4.24, р = 0.04). After a 30-day anti-inflammatory treatment with Lacto eyedrops, mean tear LF concentration plus or minus SD increased by 47% to 1.78 ± 0.7 g/l in the affected eyes. A corneal sensation score of 1 to 9 was 12.4 times more common in HSK eyes than in fellow eyes (OR = 12.4; 95% CI, 2.0–76.8), which reflects neurosensory abnormalities in the affected eye. Corneal sensation loss, was, however, more common in HSK eyes with a low tear Lf concentration than in fellow eyes with a low tear Lf concentration. Median basal tear production (as assessed by Schirmer’s II test) was as low as 7-8 mm in eyes with a low tear Lf concentration and as high as 13-16 mm in eyes with a high tear Lf concentration (p < 0.05). There was a direct correlation between the basal tear production and the tear Lf concentration (r=0.45; p < 0.05). Among study patients with recurrent HSK, 24.9% showed baseline microbiological evidence of potentially pathogenic or fungal organisms in the conjunctiva. A course of multicomponent anti-inflammatory treatment with Lacto eyedrops contributed to complete removal of these organisms. Conclusion: We determined mean tear Lf concentrations in affected and fellow eyes of patients with recurrent HSK, and established certain relationships between functional characteristics of the ocular surface and tear Lf concentrations in these eyes. A disinfecting effect of Lacto eyedrops against any microorganisms present in the conjunctival sac of patients with recurrent HSK was confirmed by the absence of culture growth on completion of the multicomponent anti-inflammatory treatment.

Abstract Background According to the literature review, this is the first study investigating tear production (TP) and intraocular pressure (IOP) in the Pygoscelis penguins living in their natural habitat. The study aimed to establish normal values for standard ocular tests in the genus Pygoscelis, namely, the Adélie (Pygoscelis adeliae), gentoo (Pygoscelis papua), and chinstrap (Pygoscelis antarctica) penguins, in four different islands of Antarctica. Sampling was made by specifically using the left eye of the penguins. The Schirmer's tear test type I (STT-I) and the Tonovet® (rebound tonometer) were used to measure the TP and the IOP, respectively. Results The mean TP and IOP values of 129 Adélie, chinstrap, gentoo, and 120 adult Adélie, gentoo penguins were determined as 10.2 ± 4.0 mm/min and 38.9 ± 13.2 mmHg, respectively. No statistical difference was detected between the penguin species for the mean IOP values, while the difference was determined in all the locations. However, statistical differences in the mean TP values were determined between all locations. Conclusion The results of this study provide a reference range of Schirmer's tear test (STT) and IOP values in Pygoscelis penguins and show that the IOP is significantly affected by locations. This result can be attributed to the harsh climatic conditions of the Antarctic Peninsula that change very quickly. The described data may help diagnose clinical pathological findings in Pygoscelis penguins. The STT and rebound tonometry appears to be safe and reproducible methods in Pygoscelis penguins, as the results were obtained quickly and were well tolerated by the birds. Based on our results, we propose that similar studies can be initiated in crowded colonies of three penguin species of this genus on the Antarctic Peninsula, the southern Shetland Islands, and other frequently visited islands in Antarctica.

The aim of the study is to assess the lacrimal gland tear production, using the Schirmer Tear Test (STT), in healthy sheep under general anesthesia and to explore the effects of applying 1% hyaluronic acid ophthalmic gel during general anesthesia. While STT values during anesthesia have been well documented in small animals such as cats and dogs, there seems to be a lack of information available for ruminants like sheep. This gap in the literature highlights the need for further research and exploration into tear production in sheep under anesthesia. The experimental research conducted on twelve adults female sheep provided valuable insights into tear production under anesthesia. By assessing tear production at various key time points the study was able to capture the changes in tear production throughout anesthesia and revealed a significant decrease in Schirmer Tear Test values in all sheep, following general anesthesia. The results showed that closing and taping the eye yielded determined better outcomes compared to administering a 1% lubricant ophthalmic gel. This finding suggests that eye care during anesthesia can impact tear production in sheep.

Simple Summary: In veterinary medicine, the use of sedative agents to perform clinical and diagnostic procedures is increasingly common. Several anesthetic drugs decrease tear flow production. In recent years, interest in the clinical efficacy of sedative and hypnotic agents for new and atraumatic routes of administration has increased. Tear film production has never been investigated in cats who received sedative agents by the intrarectal route (IR). The aim of this study is to compare the clinical effects of a mixture of dexmedetomidine, ketamine and midazolam on tear film flow administered by the IR versus the intramuscular route (IM). Cats are often easily stressed and uncooperative. The use of sedative agents in the feline species is widely used to perform even minor clinical and diagnostic procedures. The aim of this study is to assess the impact on tear film production of the intrarectal route (IR) administration of a mixture of dexmedetomidine, ketamine and midazolam in comparison with the intramuscular (IM) one. A group of twenty cats were involved in a randomized and blinded clinical trial. A clinical and ophthalmological examination was conducted on the cats. The IR group received dexmedetomidine 0.003 mg kg−1, ketamine 4 mg kg−1 and midazolam 0.4 mg kg−1; the IM group received dexmedetomidine 0.003 mg kg−1, ketamine 2 mg kg−1 and midazolam 0.2 mg kg−1. A Shirmer tear test I (STT- I) was conducted 1 h before sedation and 2′, 10′, 20′, 30′, 40′, and 80′ post drug administration. The reaction to STT-I administration was also evaluated. The IM group has a lower mean tear production than the IR group for all time points evaluated. Cats in the IM group showed less reaction to STT-I administration. This study may suggest that the effect of sedative agents administered by the IR route has a lower incidence on tear production than the IM one. The use of eye lubricant is recommended in any case. [ABSTRACT FROM AUTHOR]

Background: According to the literature review, this is the first study investigating tear production (TP) and intraocular pressure (IOP) in the Pygoscelis penguins living in their natural habitat. The study aimed to establish normal values for standard ocular tests in the genus Pygoscelis, namely, the Adélie (Pygoscelis adeliae), gentoo (Pygoscelis papua), and chinstrap (Pygoscelis antarctica) penguins, in four different islands of Antarctica. Sampling was made by specifically using the left eye of the penguins. The Schirmer's tear test type I (STT-I) and the Tonovet® (rebound tonometer) were used to measure the TP and the IOP, respectively. Results: The mean TP and IOP values of 129 Adélie, chinstrap, gentoo, and 120 adult Adélie, gentoo penguins were determined as 10.2 ± 4.0 mm/min and 38.9 ± 13.2 mmHg, respectively. No statistical difference was detected between the penguin species for the mean IOP values, while the difference was determined in all the locations. However, statistical differences in the mean TP values were determined between all locations. Conclusion: The results of this study provide a reference range of Schirmer's tear test (STT) and IOP values in Pygoscelis penguins and show that the IOP is significantly affected by locations. This result can be attributed to the harsh climatic conditions of the Antarctic Peninsula that change very quickly. The described data may help diagnose clinical pathological findings in Pygoscelis penguins. The STT and rebound tonometry appears to be safe and reproducible methods in Pygoscelis penguins, as the results were obtained quickly and were well tolerated by the birds. Based on our results, we propose that similar studies can be initiated in crowded colonies of three penguin species of this genus on the Antarctic Peninsula, the southern Shetland Islands, and other frequently visited islands in Antarctica. Highlights: • This study is the first to investigate tear production (TP) and intraocular pressure (IOP) in Pygoscelis penguins. • TP value was obtained by Schirmer's tear test type I (STT- I), while the IOP was measured with the help of Tonovet® (rebound tonometer). • No clinical macroscopic findings affecting the eyelids, third eyelid, cornea, or ocular eye surface were found during the clinical examination of the penguins. • There was no difference in TP values between species of this genus and locations. There was no statistically significant difference between species in IOP mean values. However, a significant difference was noticed among the locations. • This study indicated that IOP in Pygoscelis penguins was significantly affected by location. [ABSTRACT FROM AUTHOR]

Background: Herpetic stromal keratitis (HSK) is an immunomodulatory disease that develops as a result of herpes simplex virus (HSV)1 or HSV2 reactivation. HSK is the most common form (20-50%) of recurrent herpetic keratitis (HK) that most commonly results in significantly reduced vision. It is well known that changes in biological compound levels in tear fluid can be indicative of the state of the ocular surface and determine whether ocular surface pathology is present, and, therefore, can be used as diagnostic markers of pathological changes in the ocular surface. Lactoferrin (LF) is one of these compounds and has been proven to have innate antibacterial, antifungal, antiviral, antiparasite, anti-inflammatory, immunomodulatory, antioxidative and other properties. Purpose: To determine tear Lf concentration in patients with recurrent acute HSK, its effect on functional characteristics of the ocular surface, and the therapeutic effect of Lacto eyedrops in the comprehensive treatment for this disorder. Material and Methods: The study was conducted at the site of Corneal Pathology Department and Immunology Laboratory of the Institute in January to December 2021. Seventeen patients (17 affected eyes and 17 fellow eyes) with recurrent acute HSK were included in the study. Mean patient age plus or minus standard deviation (SD) was 48.7 ± 16.0 years. The ophthalmological examination included biomicroscopy of the bulbar conjunctiva and cornea, fluorescein test, determination of corneal sensation and basal tear production (Schirmer's II test), and microbiological examination of the conjunctiva. Tear Lf concentration was determined by a human Lf enzyme-linked immunosorbent assay (ELISA) kit (Elabscience Biotechnology, Inc., Wuhan, China). The results were photometrically measured at 450 nm with an ELISA reader (Stat Fax 2100, Awareness Technology Inc, Palm City, FL). Lacto eyedrops were administered two times a day for 30 days. Tear Lf concentrations were determined at baseline and at day 30. Results: Mean tear LF concentration plus or minus SD in eyes of patients with recurrent HSK was 1.21 ± 0.52 g/l, with no significant difference between the affected eye and fellow eye. However, a subnormal tear LF concentration was more common in the affected eye than in the fellow eye (X² = 4.24, p = 0.04). After a 30-day anti-inflammatory treatment with Lacto eyedrops, mean tear LF concentration plus or minus SD increased by 47% to 1.78 ± 0.7 g/l in the affected eyes. A corneal sensation score of 1 to 9 was 12.4 times more common in HSK eyes than in fellow eyes (OR = 12.4; 95% CI, 2.0-76.8), which reflects neurosensory abnormalities in the affected eye. Corneal sensation loss, was, however, more common in HSK eyes with a low tear Lf concentration than in fellow eyes with a low tear Lf concentration. Median basal tear production (as assessed by Schirmer's II test) was as low as 7-8 mm in eyes with a low tear Lf concentration and as high as 13-16 mm in eyes with a high tear Lf concentration (p < 0.05). There was a direct correlation between the basal tear production and the tear Lf concentration (r=0.45; p < 0.05). Among study patients with recurrent HSK, 24.9% showed baseline microbiological evidence of potentially pathogenic or fungal organisms in the conjunctiva. A course of multicomponent anti-inflammatory treatment with Lacto eyedrops contributed to complete removal of these organisms. Conclusion: We determined mean tear Lf concentrations in affected and fellow eyes of patients with recurrent HSK, and established certain relationships between functional characteristics of the ocular surface and tear Lf concentrations in these eyes. A disinfecting effect of Lacto eyedrops against any microorganisms present in the conjunctival sac of patients with recurrent HSK was confirmed by the absence of culture growth on completion of the multicomponent anti-inflammatory treatment. [ABSTRACT FROM AUTHOR]

Contact lenses are becoming more and more popular. Today, a contact lens is a high-tech biocompatible device capable of retaining moisture and allowing oxygen to reach the cornea, thereby preventing complications. But contact lenses are a medical product and wearing them is associated with certain risks. The work reveals some mechanisms of the occurrence of contact lens-related complications, presents the classification of general and metabolic complications. Complications of the epithelial, stromal and endothelial layers of the cornea are described. Characteristics of infectious and allergic complications of the eye surface are presented. Variants of mechanical damage to the surface of the eye by contact lenses are described. Recommendations for the treatment and prevention of contact lens-related complications are provided. [ABSTRACT FROM AUTHOR]

Purpose: Ophthalmic diagnosis in many avian species remains hindered by a lack of normative values. This study aimed to establish normal ophthalmic parameters for select diagnostic tests in clinically normal Quaker parrots. Methods: Ninety‐six captive Quaker parrots aged 8–18 years underwent ophthalmic examination to include assessment of neuro‐ophthalmic reflexes, phenol red thread test, rebound tonometry, fluorescein staining, palpebral fissure length measurements, slit lamp biomicroscopy, indirect ophthalmoscopy, and ocular ultrasound biometry. Results: Menace response, dazzle reflex, and direct pupillary light reflex were present for all Quaker parrots. Tear production (mean ± SD) was 13.3 ± 4.0 mm/15 s and intraocular pressure (IOP, mean ± SD) was 10.6 ± 1.4 and 6.0 ± 1.3 mmHg in the D and P rebound tonometer calibration settings, respectively. For IOP measurement, D and P calibration settings were not interchangeable, with the lesser variation of the D setting preferred in the absence of a gold standard. Ultrasound measurement of the anterior chamber depth increased with age and males had longer axial globe and vitreous lengths. Incidental adnexal and ocular lesions, identified in 36/96 (37.5%) of Quaker parrots, did not statistically affect the created reference data. Conclusions: This work provides reference values and clinical findings to assist with monitoring the health of wild populations and maintaining the health of captive Quaker parrots. [ABSTRACT FROM AUTHOR]

PURPOSE: To develop a new dry eye syndrome (DES) animal model by injecting mitomycin C (MMC) into the lacrimal glands (LGs) of rabbits evaluated by clinical examinations. MATERIALS AND METHODS: A volume of 0.1 mL of MMC solution was injected in the LG and the infraorbital lobe of the accessory LG of rabbits for DES induction. Twenty male rabbits were separated into three groups, the control group, and different concentration of MMC, (MMC 0.25: 0.25 mg/mL or MMC 0.50: 0.5 mg/mL) were tested. Both MMC-treated groups received MMC twice injection on day 0 and day 7. Assessment of DES included changes in tear production (Schirmer's test), fluorescein staining pattern, conjunctival impression cytology, and corneal histological examination. RESULTS: After MMC injection, no obvious changes in the rabbit's eyes were noted by slit-lamp examination. Both the MMC 0.25 and the MMC 0.5 groups revealed decreased tear secretion after injection, and the MMC 0.25 group showed a continuous decrease in tear secretion up to 14 days. Fluorescent staining showed punctate keratopathy in both MMC-treated groups. In addition, both MMC-treated groups demonstrated decreased numbers of conjunctival goblet cells after injection. CONCLUSION: This model induced decreased tear production, punctate keratopathy, and decreased numbers of goblet cells, which are consistent with the current understanding of DES. Therefore, injecting MMC (0.25 mg/mL) into the LGs is an easy and reliable method to establish a rabbit DES model which can apply in new drug screening.

Background: Keratitis is a common cause of eye diseases in horses, often resulting in complete loss of vision. Aim: The purpose of the paper is to study the features of the clinical picture of primary and secondary keratitis in horses, depending on the form of the course of the disease. Methods: The study was conducted in 2019 at 22 private horse breeding farms. The study involved 80 horses with keratitis, which were divided into two equal groups depending on the diagnosis of primary or secondary keratitis. Results: The effectiveness of the therapies was compared 1, 3 and 6 months after the start of treatment. Following a 1-month therapy, only a minority of horses with primary keratitis had their eye functions fully restored, the number of horses with macula was 2 times higher (p ≤ 0.05), the number of horses with nebula was 7 times higher (p ≤ 0.001), and leukomas were reported in most of the cases (p ≤ 0.0001). Conclusion: The effectiveness of the therapy for keratitis is directly related to the peculiarities of treatment and adherence to the regimen. [Open Vet J 2022; 12(6.000): 830-838]

Objective: To evaluate the relationship between lacrimation and age in a homogeneous group of healthy beagle dogs during the first year of life. Materials and methods: Schirmer tear test I (STT I) was performed at an interval of 12–15 days in both eyes of 16 clinically healthy beagle dogs (eight males and eight females) from 94 to 361 days of age. Three different quadratic polynomial regression equations were estimated for the variation in lacrimation: (1) for the entire period (19 observations), (2) for observations 1–4 (days 94–136), and (3) for observations 5–19 (days 150–361). Results: By fitting quadratic regression equations to different phases of tear production during the dog's first year of life, it was possible to see that with each day of life, lacrimation increased 0.08 times (8%). From days 94 to 136, however, lacrimal production fell 1.1 times with each day of life. From day 150 to 361, production increased by 0.02 (2%) each day of life. In addition, there was a positive significant and moderate linear correlation between body weight and STT I values (p =.01). Conclusion: In dogs, during the first year of life, STT I data distribution is parabolic in shape. Age significantly affected tear production. STT I decreased at approximately 108–121 days of age and increased thereafter. Body weight was a significant factor for STT I in young dogs. The establishment of this normal pattern of lacrimation is important for both clinical practitioners and laboratory studies. [ABSTRACT FROM AUTHOR]

Normal values of tear production (STT) and intraocular pressure (IOP) have not been reported in conscious red deer to date. The objective was to determine the normal range of STT and IOP in clinically healthy, conscious red deer (Cervus elaphus) by utilizing a chute restraint. A total of 60 red deer were examined in this study. Both eyes of all red deer underwent a complete ophthalmic examination, including evaluation of tear production with the Schirmer tear test (STT) and assessment of intraocular pressure (IOP) with rebound tonometry, employing the TonoVet® device. The mean ± standard deviation of STT values were 18.35 ± 4.54 mm/30 s in the right eye and 17.87 ± 4.12 mm/30 s in the left; for both eyes, 18.11 ± 4.33 mm/30 s, with a reference range of 17.33–18.89 mm/30 s. IOP was as follows: 26.96 ± 4.42 mmHg in the right eye and 26.67 ± 3.80 mmHg in the left; for both eyes, it was 26.81 ± 4.11 mmHg, with a reference range of 26.07–27.55 mm/30 s. No statistically significant differences were observed between the IOP and STT values of the right and left eyes. This study provides a reference range for the STT and IOP in healthy red deer, showing that STT determination of tear production, and rebound tonometry to evaluate the IOP methods, are practical methods for ophthalmic examination in deer.

We herein report a 76-year-old male who presented to the ophthalmology clinic after complaining from excessive lacrimation for ~6 months prior to presentation. He reports previously undergoing a nasolacrimal recanalization procedure in attempts to resolve his symptoms, but reported no improvement. On examination, a mass on the nasal conjunctiva around the medial canthus of the right eye was noted and subsequently excised. The findings support the diagnosis of low-grade follicular lymphoma. The patient was referred to radiation oncology for radiation therapy and received a total dose of 2400 cGy. Most ocular adnexal lymphomas are B-cell in origin, with follicular lymphomas being one of the rarest forms of such lymphomas. The most common translocation reported in over 85% of follicular lymphomas of the ocular adnexa is t(14; 18) (q32; q21). Traditional treatment options typically include a mix of chemical, surgical, and radio-oncological interventions. [ABSTRACT FROM AUTHOR]

Alice T Epitropoulos,1,2 Sheraz M Daya,3 Cynthia Matossian,4 Alan G Kabat,5,6 Gretchen Blemker,5 Kristen Striffler,5 Laura Hendrix,5 Marian Macsai,5 Andrea Gibson5 1Ophthalmic Surgeons & Consultants of Ohio, the Eye Center of Columbus, Columbus, OH, USA; 2Department of Ophthalmology, the Ohio State University Wexner Medical Center, Columbus, OH, USA; 3Centre for Sight, London, UK; 4Matossian Eye Associates, Pennington, NJ, USA; 5Oyster Point Pharma, Inc, Princeton, NJ, USA; 6Salus University, Elkins Park, PA, USACorrespondence: Andrea Gibson, Oyster Point Pharma, Inc, 202 Carnegie Center, Suite 109, Princeton, NJ, 08540, USA, Tel +1-860-227-1034, Fax +1-856-433-8439, Email agibson@oysterpointrx.comPurpose: To evaluate OC-01 [varenicline solution nasal spray (VNS)] tear production and symptom outcomes in patients with dry eye disease by age, gender, race, ethnicity, and artificial tear use status.Patients and Methods: Adults ≥ 22 years of age diagnosed with dry eye disease, with Ocular Surface Disease Index score ≥ 23, corneal fluorescein staining score ≥ 2 in ≥ 1 region or ≥ 4 for all regions, and baseline Schirmer Test Score (STS) ≤ 10 mm, with no restrictions on eye dryness score (EDS). Efficacy was assessed using integrated data from ONSET-1 and ONSET-2 [vehicle control (VC), n=294; OC-01 VNS 0.03 mg, n=308]. Subgroups included age (≤ 55, 56− 65, > 65 years), gender (male, female), race (White, Black or African American), ethnicity (Hispanic or Latino, Not Hispanic or Latino), and artificial tear use (yes, no). Analysis of covariance models, with the covariates treatment, study site, and baseline severity measures, were used to calculate treatment−VC differences. Consistency of effect among subgroups was evaluated by conducting interaction tests.Results: Consistency of treatment effect across subgroups was observed for all endpoints, with P value for all treatment−subgroup interaction terms > 0.05. For % of patients with ≥ 10mm improvement in STS and least squares (LS) mean change from baseline in STS and EDS, there was improvement in tear production across demographic group categories. Artificial tear use did not change STS or EDS outcomes with OC-01 VNS.Conclusion: OC-01 VNS improved tear production and patient-reported symptom outcomes across a broad range of patients by age, gender, race, and ethnicity, and regardless of artificial tear use status at baseline. OC-01 VNS demonstrated a consistent benefit across an extensive range of patients with dry eye disease.Keywords: bioactivation, dry eye disease, nicotinic acetylcholine receptor, tear production, varenicline nasal spray

Objective: To describe normative ocular surface and aqueous tear testing data for cats of various cephalic conformation. Animals studied: Fifty‐three healthy adult cats (11 British Shorthair, 11 Burmese, 10 Devon Rex, 10 Scottish Fold, and 11 Sphynx). Procedures: Blink rate, corneal tactile sensation (CTS), and Schirmer tear test with or without topical anesthesia (STT‐1, STT‐2) and with nasolacrimal stimulation (NL‐STT1, NL‐STT2) were assessed. Palpebral fissure length (PFL) and skull morphology were measured, and cephalic index (CI) and craniofacial ratio (CFR) calculated. Results: Mean ± SD test results were as follows: blink rate (5.0 ± 2.3 blinks/min), CTS (3.2 ± 0.7 cm), STT‐1 (11.2 ± 4.3 mm/min), STT‐2 (6.7 ± 3.6 mm/min), NL‐STT1 (13.4 ± 5.7 mm/min), NL‐STT2 (13.5 ± 5.2 mm/min), and PFL (2.0 ± 0.2 cm). Corneal sensitivity did not differ significantly among breeds (p =.152) but was negatively correlated with body weight (r = −.32, p =.019). STT‐1 significantly differed among breeds (p <.001) and was lowest in Sphynx cats (8.7 ± 4.3 mm/min). A positive correlation was detected between STT‐1 values at 30 and 60 s (r =.98; p <.001). The nasolacrimal reflex significantly increased STT in anesthetized and unanesthetized eyes (approximately +100% and +20%, respectively; p ≤.002). STT‐1 tended to be higher in intact versus neutered cats (p =.062). Age did not impact any test result (p ≥.085). Conclusions: Normative data described here serve as a baseline for future studies assessing ocular surface disease in multiple feline breeds. Unlike dogs, brachycephalic cats did not have lower CTS or STT‐1 than non‐brachycephalic cats. [ABSTRACT FROM AUTHOR]

Objective: To characterize the ocular surface parameters and determine the prevalence of ocular pathology in Shih Tzu dogs. Animal Studied: Fifty Shih Tzu dogs (28 male, 22 female). Procedures: Each dog underwent a complete ophthalmic examination (recording any pathology) and a series of diagnostics, allowing for a 10 min‐interval between tests: intraocular pressure (IOP), blink rate, palpebral fissure length (PFL), corneal tactile sensation (CTS), Schirmer tear test and nasolacrimal reflex without (STT‐1, NL‐STT1) and with topical anesthesia (STT‐2, NL‐STT2), tear ferning, strip meniscometry test (SMT), tear film breakup time (TFBUT), and punctate fluorescein staining (PFS) of the cornea. Results: Mean ± SD test values were as follows: IOP (17.9 ± 3.7 mmHg), blink rate (2.4 ± 1.4 blinks/min), PFL (23.8 ± 1.8 mm), CTS (1.8 ± 0.7 cm), STT‐1 (22.0 ± 5.5 mm/min), NL‐STT1 (24.2 ± 4.7 mm/min), STT‐2 (16.9 ± 6.5 mm/min), NL‐STT2 (18.5 ± 7.5 mm/min), SMT (7.5 ± 3.5 mm/5 s), TFBUT (5.3 ± 2.4 s), tear ferning (1.3 ± 0.7), and PFS (1.6 ± 0.6). PFL was significantly greater in male vs. female Shih Tzus (p<.001). Age was negatively correlated with TFBUT results (r = −0.31, p =.027). Lagophthalmos was observed in 82% eyes. Ocular surface pathology was common, including adnexal abnormalities (100% eyes with caruncular trichiasis and medial lower lid entropion) and corneal opacification (27% pigmentation, 20% fibrosis, 12% neovascularization). Conclusions: Qualitative tear film deficiency (low TFBUT), along with several anatomical abnormalities that promote ocular irritation and reduce globe protection, together help explain the concerningly high prevalence of ocular surface disease in the Shih Tzu breed. Prophylactic measures (e.g., medial canthoplasty, topical lubrication) could be considered to improve ocular health in Shih Tzus. [ABSTRACT FROM AUTHOR]

Background: The orbital glands, viz. lacrimal gland, superficial and deep gland of third eyelid (LG, SGT and HG), are important for normal eye functions. These glands have different functions in various animals. The information about the enzyme histochemical nature of prenatal orbital glands in Indian buffalo seems to be unavailable. Therefore, the study was planned on orbital glands of six full term recently died fetuses from animals with dystocia. Methods: The frozen sections of all these glands were subjected to standard localization protocols for Alkaline Phosphatase (AKPase), Glucose 6 phosphatase (G-6-Pase), Lactate dehydrogenase (LDH), Succinate dehydrogenase (SDH), Glucose 6 phosphate dehydrogenase (G-6-PD), Nicotinamide Adenine Dinucleotide Hydrogen Diaphorase (NADHD), Nicotinamide Adenine Dinucleotide Phosphate Hydrogen diaphorase (NADPHD), Dihydroxy phenylalanine oxidase (DOPA-O), Tyrosinase, non-specific esterase (NSE) and Carbonic anhydrase (CAse). Results: The results revealed a mixed spectrum of reaction for the above enzymes in LG, SGT and HG which ranged from moderate (for LDH in SGT) to intense (for most of the enzymes in all three glands). However, DOPA-O, Tyrosinase and CAse did not show any reaction. From the present study, it can be postulated that the orbital glands of fetus have a high activity of metabolism as it has many developmental and functional activities which were mediated with the higher activity of the enzymes involved. [ABSTRACT FROM AUTHOR]

The aim of this study is to determine normal tear secretion levels in healthy Van cats by PRT test and to investigate the relationship between tear level and gender and age. Twenty adult Van cats, who were brought to the clinic and found to be healthy after examination, were included in the study. These cats were tested without the use of any medicine. The cats who took part in the experiment ranged in age from two to five years, with a mean age of 3.25±1.07. There were 12 female cats and 8 male cats in the group. Commercial kits were utilized for the testing. The mean PRT value for the Van cat was determined as 12.3±1.895 (9-18) mm/15 sec. Males had a mean of 11.875±1.246 (10-13) mm/15 sec. and females had a mean of 12.583±2.234 (9-18) mm/15 sec. There was no statistically significant difference in the mean of males and females in the group and no difference as age increased (p>0.05). In conclusion, the PRT test findings in this study can be used as reference values in the diagnosis of eye diseases affecting the tear production ability of Van cats. [ABSTRACT FROM AUTHOR]

Cats are often easily stressed and uncooperative. The use of sedative agents in the feline species is widely used to perform even minor clinical and diagnostic procedures. The aim of this study is to assess the impact on tear film production of the intrarectal route (IR) administration of a mixture of dexmedetomidine, ketamine and midazolam in comparison with the intramuscular (IM) one. A group of twenty cats were involved in a randomized and blinded clinical trial. A clinical and ophthalmological examination was conducted on the cats. The IR group received dexmedetomidine 0.003 mg kg−1, ketamine 4 mg kg−1 and midazolam 0.4 mg kg−1; the IM group received dexmedetomidine 0.003 mg kg−1, ketamine 2 mg kg−1 and midazolam 0.2 mg kg−1. A Shirmer tear test I (STT- I) was conducted 1 h before sedation and 2′, 10′, 20′, 30′, 40′, and 80′ post drug administration. The reaction to STT-I administration was also evaluated. The IM group has a lower mean tear production than the IR group for all time points evaluated. Cats in the IM group showed less reaction to STT-I administration. This study may suggest that the effect of sedative agents administered by the IR route has a lower incidence on tear production than the IM one. The use of eye lubricant is recommended in any case.

Background The orbital glands, viz. lacrimal gland, superficial and deep gland of third eyelid (LG, SGT and HG), are important for normal eye functions. These glands have different functions in various animals. The information about the enzyme histochemical nature of prenatal orbital glands in Indian buffalo seems to be unavailable. Therefore, the study was planned on orbital glands of six full term recently died fetuses from animals with dystocia. Methods The frozen sections of all these glands were subjected to standard localization protocols for Alkaline Phosphatase (AKPase), Glucose 6 phosphatase (G-6-Pase), Lactate dehydrogenase (LDH), Succinate dehydrogenase (SDH), Glucose 6 phosphate dehydrogenase (G-6-PD), Nicotinamide Adenine Dinucleotide Hydrogen Diaphorase (NADHD), Nicotinamide Adenine Dinucleotide Phosphate Hydrogen diaphorase (NADPHD), Dihydroxy phenylalanine oxidase (DOPA-O), Tyrosinase, non-specific esterase (NSE) and Carbonic anhydrase (CAse). Results The results revealed a mixed spectrum of reaction for the above enzymes in LG, SGT and HG which ranged from moderate (for LDH in SGT) to intense (for most of the enzymes in all three glands). However, DOPA-O, Tyrosinase and CAse did not show any reaction. From the present study, it can be postulated that the orbital glands of fetus have a high activity of metabolism as it has many developmental and functional activities which were mediated with the higher activity of the enzymes involved.

Background: Keratitis is a common cause of eye diseases in horses, often resulting in complete loss of vision. Aim: The purpose of this article is to study the features of the clinical picture of primary and secondary keratitis in horses, depending on the form of the course of the disease. Methods: The study was conducted in 2019 at 22 private horse breeding farms. The study involved 80 horses with keratitis, which were divided into two equal groups depending on the diagnosis of primary or secondary keratitis. Results: The effectiveness of the therapies was compared 1, 3, and 6 months after the start of treatment. Following a 1-month therapy, only a minority of horses with primary keratitis had their eye functions fully restored, the number of horses with macula was two times higher (p = 0.05), the number of horses with nebula was seven times higher (p = 0.001), and leukomas were reported in most of the cases (p = 0.0001). Conclusion: The effectiveness of the therapy for keratitis is directly related to the peculiarities of treatment and adherence to the regimen. [ABSTRACT FROM AUTHOR]

Objectives: The aims of this study were to evaluate and compare the effects that dexmedetomidine and methadone, either alone or in combination, have on the ocular variables of healthy adult cats when administered intramuscularly, as well as their reversal with atipamezole. Methods: A randomized crossover blinded study of 10 healthy cats was used to assess the effect of 0.2 mg/kg methadone (MET), 7.5 μg/kg dexmedetomidine (D7), 10 μg/kg dexmedetomidine (D10), 7.5 μg/kg dexmedetomidine and 0.2 mg/kg methadone (DM7) and 10 μg/kg dexmedetomidine and 0.2 mg/kg methadone (DM10) on intraocular pressure (IOP), tear production and pupil diameter (PD). The animals were evaluated for 30 mins. Afterwards, atipamezole was administered and ocular variables were evaluated for 30 mins. Results: D10, DM7 and DM10 significantly decreased mean IOP but MET or D7 did not. Tear production decreased significantly in all treatments, corresponding to 18%, 59%, 63%, 86% and 98% in MET, D7, D10, DM7 and DM10, respectively. PD increased in all treatments, but MET showed the highest PD. Thirty minutes after atipamezole (RT30), IOP returned to baseline with no difference between groups, and there was a significant increase in tear production, but the means were still different from baseline. Conclusions and relevance: Dexmedetomidine decreases IOP and tear production but increases PD in healthy cats. Atipamezole can partly reverse those alterations. Low-dose dexmedetomidine (7.5 µg/kg) promotes sedation without changing the IOP. All protocols significantly decrease tear production, and Schirmer tear test after sedation is not representative of non-sedated values. Methadone induces quick onset mydriasis without changing the IOP. [ABSTRACT FROM AUTHOR]

Objective: The objective of the present study was to examine the effect of different light intensities on tear production, corneal thickness, and intraocular pressure in broilers. Animals studied: Both eyes of 72 male broilers were evaluated in this study. Materials and Methods: Broilers were divided into the following three groups: low light intensity (n = 24, 5 lux), moderate light intensity (n = 24, 20 lux), and high light intensity (n = 24, 80 lux). The eyes of all birds (n = 72) underwent a complete ophthalmic examination, which included the Schirmer tear test (STT‐I), intraocular pressure (IOP), and the central cornea thickness measurement (CCT). The effect of light intensity on the Schirmer test, intraocular pressure, and central corneal thickness values was examined at eye and animal level (right and left eyes separately and cumulatively/no distinguishing left or right) by using one‐way ANOVA. Results: At the animal level, without discrimination of left and right eye measurements, statistically significant differences were found between 5–20 and 20–80 lux groups on IOP measurements (p <.05). The difference in CCT measurements between the 5 and 20 lux groups was statistically significant (p <.05), and the corneal thickness of the 5 lux group animals was found to be statistically significant and higher than the 20 lux group (p <.05). Conclusions: In conclusion, light intensity has an influence on eye health in broilers. Present results may attribute to the future studies as a reference value for broilers raised under different light intensities. [ABSTRACT FROM AUTHOR]

The aim of this systematic review is to summarize outcomes of studies focused on the effects of opioids, injectable sedative and anaesthetic drugs and inhalant anaesthetics on tear production in dogs. This manuscript complements the systematic review describing the effect of anaesthetics on intraocular pressure in dogs (Pierce-Tomlin et al. 2020). Databases used A detailed search of scientific references has been performed. PubMed, Web of Science, Science Direct and Google Scholar databases were used to search for sources using free text terms 'Dog' or 'Canine', 'Anaesthesia' or 'Anaesthetic' or 'Sedative' or 'Opioid' or the name of used opioids, sedative and anaesthetic drugs and 'Tear' or 'Schirmer' or 'Lacrimation'. The time frame searched was from 1960 to October 2021. Any published manuscripts that were concerned with sedative or anaesthetic drugs administered systemically in the dog and tear production were evaluated. Low doses of α 2 -adrenoceptor agonists, neuroleptics, benzodiazepines, opioids, propofol or alfaxalone administered alone have no clinically significant effect on aqueous tear production in healthy dogs measured by the Schirmer tear test I (STT-I). Intramuscular injection of ketamine increases STT-I values. Higher doses of α 2 -adrenoceptor agonists and combinations of anaesthetics, including inhaled anaesthetics, always clinically significantly decrease tear production. [ABSTRACT FROM AUTHOR]

Jonathan Lilley,1 Erin C O’Neil,1 Vatinee Y Bunya,1 Kennedy Johnson,1 Gui-Shuang Ying,2 Peiying Hua,2 Mina Massaro-Giordano1 1Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA; 2Center for Preventive Ophthalmology and Biostatistics, University of Pennsylvania, Philadelphia, PA, USACorrespondence: Mina Massaro-GiordanoDepartment of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 51 N. 39th Street, Philadelphia, PA, 19104, USATel +1 215-662-9393Email mina@pennmedicine.upenn.eduPurpose: To assess the efficacy and safety of an intranasal tear neurostimulator (ITN) device in Sjögren syndrome (SS) patients.Methods: This was a two-visit prospective, randomized, controlled, same-day crossover study in participants with SS. Inclusion criteria were assessed at a baseline screening visit and included an Ocular Surface Disease Index (OSDI) score ≥ 13, and a Schirmer with anesthesia ≤ 10 mm/5 min (in at least one eye), with a cotton swab stimulation induced increase of ≥ 4 mm in the same eye. Participants returned for the application visit, where they received intranasal and extranasal applications of the ITN in random sequence, separated by at least 60 min. Schirmer scores were measured in both eyes after each application and compared to baseline values. Generalized linear models were performed to compare the change in Schirmer scores from baseline, and generalized estimating equations were used to account for correlations from repeated measurements in the same eye and measurements from two eyes of the same patient.Results: Fifty-five participants were screened and 35 were enrolled (all female), ranging in age from 31 to 72 years (mean, 57 years). The baseline OSDI score ranged from 14 to 91 (mean, 50.5), and the baseline Schirmer score had a mean (SD) of 6.4 (3.5) ranging from 0 to 20 (mm/5min). Improvement in Schirmer scores was significantly greater for intranasal device application (13.5 mm/5min, 95% CI: 10.4, 16.5) compared to extranasal device application (0.8mm/5min, 95% CI: − 0.9, 2.4) (p< 0.0001). The effects of the intranasal device application were significant regardless of the participant’s baseline Schirmer score and systemic SS medication usage (p< 0.05).Conclusion: Intranasal application of the ITN device significantly increased tear production in a subset of SS patients compared to baseline and was more effective than extranasal application. While production of the ITN device was recently discontinued, our findings suggest that other therapies that neurostimulate the lacrimal function unit may be effective in a subset of SS patients.Keywords: Sjögren syndrome, intranasal tear neurostimulation, tear production

Background: Investigation of the pathogenesis of dry eye disease (DED) in corneal and conjunctival cicatrization secondary to severe burns to the eye as well as optimization of the management of this condition is an important and relevant task of clinical ophthalmology. Purpose: To optimize the management of DED in corneal and conjunctival cicatrization secondary to severe burns to the eye on the basis of tear production studies. Material and Methods: Forty patients (60 eyes) with DED and corneal and conjunctival cicatrization secondary to severe burns to the eye and showing various reductions in Schirmer test 1 scores were included in the study. Tear substitutes (Tear Naturale; Alcon, Fort Worth, TX) or Vidisic® gel (Mann Pharma, Berlin, Germany) were administered four times a day for eyes with mild or moderate dry eye, and six times a day for eyes with severe dry eye, and tear production was assessed at 2 weeks and at 3 months. Results: At two weeks, among the eyes treated with Vidisic gel, Schirmer test score improved from 12 mm to 13 mm (p > 0.05) for eyes with mild dry eye, from 6.5 mm to 8.4 mm for eyes with moderate dry eye, and from 3.1 mm to 6.3 mm for eyes with severe dry eye. In addition, among the eyes treated with teas substitutes, Schirmer test score improved from 11 mm to 13 mm for eyes with mild dry eye, from 6.1 mm to 8.1 mm for eyes with moderate dry eye, and from 2.6 mm to 4.4 mm for eyes with severe dry eye (p < 0.05). At three months, patients who were taking their medication as per schedule had approximately the same scores as at two weeks, whereas those who discontinued taking their medication or were taking it irregularly had approximately the same scores as at baseline. Conclusion: Our findings highlight the necessity of continuous tear substitute treatment for patients with DED and corneal and conjunctival cicatrization secondary to severe burns to the eye.

Impaired tear production – a common sign of keratoconjunctivitis sicca (KCS) – is associated with qualitative or quantitative tear deficiency. OTX-101 0.09% is a novel, nanomicellar formulation of cyclosporine A approved in the US for increasing tear production in patients with KCS. We present a pooled analysis of the phase 2b/3 and phase 3 studies evaluating the effect of OTX-101 on tear production in a subgroup of patients with keratoconjunctivitis sicca with severely impaired tear production (Schirmer's score <5 mm in either eye at baseline). In these randomized, double-masked studies, patients instilled 1 drop OTX-101 or vehicle per eye twice daily for 84 days. Pooled efficacy endpoints included percent (%) of patients with ≥10 mm change from baseline and mean change from baseline in Schirmer's score at day 84. Pooled safety endpoints included adverse event monitoring. Subgroup analyses included 133 and 113 patients receiving OTX-101 and vehicle, respectively. Mean baseline (BL) Schirmer's score ± standard deviation was 2.7 ± 1.2 for OTX-101 and 2.5 ± 1.1 mm for vehicle (P =.3203). On day 84, number (%) of patients with ≥10 mm Schirmer's score change from baseline was 30 (22.6%) and 12 (10.6%, P =.0168); mean change from baseline ± standard deviation was 5.5 ± 8.0 and 3.6 (6.0, P =.0405) mm for OTX-101 and vehicle, respectively. Adverse events were mostly mild and did not require treatment. OTX-101 administered twice daily for 84 days significantly improved tear production vs vehicle in patients with severely impaired tear production, as evidenced by significantly larger proportion of patients with ≥10 mm increases from baseline and higher mean change from baseline in Schirmer's scores [ABSTRACT FROM AUTHOR]

Vinod Burade,1 Rishit Zalawadia,1 Alpesh Patel,1 Abayomi Ogundele2 1Sun Pharmaceutical Industries Limited, Vadodara, Gujarat, India; 2Sun Pharmaceutical Industries, Inc, Princeton, NJ, USACorrespondence: Abayomi OgundeleSun Pharmaceutical Industries, Inc, Princeton, NJ, USATel +1 (609) 720-5389Email Abayomi.Ogundele@sunpharma.comIntroduction: Cyclosporine ophthalmic solution 0.09% (CsA 0.09% sol) is approved to increase tear production in patients with keratoconjunctivitis sicca. This study evaluated the efficacy of CsA 0.09% sol vs cyclosporine ophthalmic emulsion 0.05% (CsA 0.05% eml) vs ciclosporin ophthalmic emulsion 0.1% (CsA 0.1% eml) in a NOD mice model.Methods: Mice were randomized and administered placebo, CsA 0.09% sol twice daily, CsA 0.05% eml twice daily, CsA 0.09% sol once daily, or CsA 0.1% eml once daily in the conjunctival sac of both eyes for 60 days. Tear volume was measured with phenol red threads at baseline and 4 hours after treatment every 15 days. On day 58, the corneal surface was observed under a slit-lamp after staining with 3% lissamine green administered into the inferior lateral conjunctival sac. On day 61, mice were euthanized, globes excised, sliced into 4 μm sections in 3 areas per section, and stained. Total number of stained goblet cell/μm was counted, and the sum per eye was averaged. Lacrimal gland tissues were removed and interleukin (IL) 1-β cytokine levels estimated.Results: Groups comprised 11 mice each, including an untreated normal and untreated diseased control group (7 groups total). CsA 0.09% sol twice daily significantly increased tear volume on day 30, 45, and 60 vs CsA 0.05% eml (P< 0.05, < 0.001, < 0.001, respectively) and vs CsA 0.1% eml on day 60 (P< 0.05); CsA 0.09% sol once daily significantly increased tear volume on day 45 vs CsA 0.05% eml (P< 0.05). Goblet cell density significantly increased with CsA 0.09% sol twice daily vs placebo and NOD control (P< 0.01 both). There was no significant difference in corneal staining and IL-1β levels with CsA 0.09% sol.Conclusion: Sixty-day treatment with CsA 0.09% sol showed comparatively improved preclinical results vs CsA 0.05% eml and CsA 0.1% eml.Keywords: cyclosporine A, goblet cell density, keratoconjunctivitis sicca, preclinical, tear production

Purpose. Development and analysis of effectiveness of predictive clinical-mathematical system of development of dry eye syndrome (DES) after phacoemulsification (PE) of senile cataract (SC).Material and methods. 120 patients (120 eyes) after SC surgery: 52 men and 68 women. Age: from 62 to 83 years (average 69.3±6.4 years). The main selection criteria for study were the absence of objective and subjective signs of DES, the presence of initial or immature SC and optimal conditions for surgery – absence of corneal pathology and mydriasis of 6 mm or more. Standard preoperative examination; 3 months after PE – Schirmer 1 test, tear break-up time, OCT mapping (Avanti RTVue XR, Optovue, USA). The above indicators were selected as potential predictors for development of algorithms for predicting of development of DES after PE of SC. Patients were divided into groups: 1st group consisted of 31 patients (31 eyes) with DES developed after PE, 2nd group consisted of 89 patients (89 eyes) without signs of DES.Results. Based on peculiarities of induced damage to structures of ocular surface in treatment of SC, two algorithms were developed to predict DES after FE of SC, which shown high prognostic characteristics: sensitivity – 80–90% and specificity – 80–87%, allowing to consider them reasonable and informative.Conclusion. The analysis of the developed clinical and mathematical system for predicting the development of DES after PE of SC showed its high efficiency. Application of developed technique in ophthalmic practice is advisable to ensure maximum medical and social rehabilitation of patients with SC.

Background: Cyclopentolate is not commonly used as mydriatic drug in veterinary medicine because of limited data on the local and systemic effects in animals. Aim: To determine the effects of topical 1% cyclopentolate hydrochloride on intraocular pressure (IOP), horizontal pupil diameter (HPD) and tear production in the cat and rabbit’s eye during the first hour and up to 36 hours after treatment. Methods: One drop of 1% cyclopentolate hydrochloride was used in the left eye in 10 clinically and ophthalmologically healthy domestic cats and 10 rabbits. IOP and HPD were recorded every five minutes during the first hour, then every 2 hours during the following 12-hour period, and at 24 and 36 hours after application. STT was measured at 30 and 60 min after treatment, then in same time points as IOP and HPD. Rebound tonometer (TonoVet®) was used to assess IOP, Jameson calliper to measure HPD and Schirmer tear test (STT) to determine the tear production. Results: 1% cyclopentolate increased IOP in cats, reaching a maximum (28.1 ± 5.4 mmHg) at T50 and in rabbits at T25 (16,7 ± 1,3 mmHg). Maximal mydriasis in cats was observed at T40 and lasted 24-36 h, but in rabbits at T25, and returned to pre-treatment values at T10h - T12h. In cats, STT decreased in both eyes 30 min after treatment and remained lower throughout the 36h period. In rabbits STT decreased in the treated eye 30 min after treatment, but all following STT measurements returned to normal pre-treatment levels. Conclusion: Study showed novel data about the effects of 1% cyclopentolate to IOP, HPD, STT in cats and rabbits. Cyclopentolate in cats caused mydriasis 20 - 40 minutes after treatment by increasing IOP at the same time, pupil diameter reached pre-treatment values 24-36 h after treatment. In rabbit’s mydriasis accurred faster, 10-25 minutes after treatment without significant IOP increase and mydriasis lasted 10-12 hours. Significant STT decrease was recorded in cats, but more likely were connected to stress factors. This drug could be considered a therapeutical alternative in rabbit more than in cats.

Objective: Evaluate the effect of repeated doses of topical 1% cyclopentolate hydrochloride alone and in combination with topical 2.5% phenylephrine on pupil diameter (PD), tear production (STT‐1), intraocular pressure (IOP), digestive function (gut motility and feces production), and heart rate (HR). Animal studied: Six healthy mares. Procedures: In a prospective, randomized, controlled, and crossover design study, the left eye of six healthy mares was administered 0.2 mL of cyclopentolate alone and in combination with 0.2 mL of phenylephrine. The drugs were administered 3 times a day for 1 day, twice a day for 1 day, and then once a day for 2 days, as commonly used in practice. Daily and two days after the last topical drug administration, HR, digestive auscultation, feces production, STT‐1, IOP, and PD were recorded. Results: The cyclopentolate alone significantly increased the horizontal and vertical PD of the treated eye from day 2 to day 6 (p <.0001) compared with the baseline value. The combination with topical phenylephrine did not have any additional effect on mydriasis compare with the cyclopentolate alone. The other ocular and digestive parameters were not affected by repeated doses of cyclopentolate alone or combined. Conclusions: Repeated administration of cyclopentolate alone or combined with phenylephrine induce a significant mydriasis for at least 48 h after the last administration in normal horses' eyes, and do not affect STT‐1, IOP, digestive function, and HR. The phenylephrine combined with the cyclopentolate did not potentiate the pupil dilation when compared with cyclopentolate alone in healthy horses. [ABSTRACT FROM AUTHOR]

Purpose. To study the dynamics of tear production and morphometric parameters of cornea after phacoemulsification of senile cataract (SC) at different postoperative terms.Material and methods. 123 patients (123 eyes) aged from 62 to 83 years were examined after phacoemulsification of SC. All patients were divided into 2 groups depending upon the level of tear production (TP): 1st group – 61 patients with normal and insufficiently lowered TP, 2nd group consisted of 62 patients with moderate and severe TP suppression. Besides standard examination methods, all patients underwent Schirmer’s – 1 test, tear breakup time (TBUT), cornea OCT, corneal endothelial cell density (CECD) before operation and on the 1st, 10th , 20th and 30th postoperative day.Results. Indices of TBUT, corneal epithelium and stromal thickness (CET and CST), CECD turned out to be lower in the eyes of patients from the second group in comparison with the 1st.Conclusion. The conducted research showed that postoperative changes of CET occur 4 times and CST 1,5 times more often in patients with moderate and severe decrease of TP rather than in eyes with normal TP. The recovery of TP on the final stage of research was found 2.6 times less in eyes of patients from the 2nd group in comparison with the 1st, which can be the evidence of possible neurotrophic corneal disorders in patients with reduced TP.

The maintenance of corneal and normal eye function is necessary for the ocular health and integrity. Tear plays an important role in defense mechanism and nutrition of eye. The Schirmer tear tests (STT I, II) are widely used in ophthalmic examination to evaluate tear production as an aid to diagnose eye diseases. The aim of this study was to compare the different effect of anesthetic combinations and their action period on tear production in healthy rabbits. Forty healthy New Zealand female rabbits (mean weight 2.34 ± 0.67 kg), four months old, were used as materials. The animals were divided into four groups as propofol + sevoflurane (PS), midazolam + sevoflurane (MS), medetomidine + ketamine + sevoflurane (MKS), and control (C) groups, and each group contained 10 rabbits. The TP (tear production) was measured from left eyes before injectable anesthesia (0. min), during sevoflurane anesthesia at 5th, 10th, 15th, 20th, 25th and 30th min, and post anesthesia (after extubation) at 10th, 20th, 30th, 60th, 120th min and 24 h after in the study groups. In group C, at the same time intervals TP were also measured. In all groups statistical differences were recorded in different times of during and post anesthesia time periods. In post anesthetic time intervals the lowest TP values were detected in PS group. The new surgical techniques on eye surgery can require long general anesthesia periods. Extending of general anesthesia duration bring along risk factors such as perioperative dry eye syndrome. Perioperative dry eye syndrome (PDES) is the most common ophthalmologic complication of the general anesthesia. As a result of this study, PS anesthetic combination decreased the TP more than MS and MKS anesthetic combination during anesthesia. Although the present study put forward shows these results in rabbits, PS, MS and MKS anesthetic combinations may show different effects on TP. [ABSTRACT FROM AUTHOR]

Background: Investigation of the pathogenesis of dry eye disease (DED) in corneal and conjunctival cicatrization secondary to severe burns to the eye as well as optimization of the management of this condition is an important and relevant task of clinical ophthalmology. Purpose: To optimize the management of DED in corneal and conjunctival cicatrization secondary to severe burns to the eye on the basis of tear production studies. Material and Methods: Forty patients (60 eyes) with DED and corneal and conjunctival cicatrization secondary to severe burns to the eye and showing various reductions in Schirmer test 1 scores were included in the study. Tear substitutes (Tear Naturale; Alcon, Fort Worth, TX) or Vidisic® gel (Mann Pharma, Berlin, Germany) were administered four times a day for eyes with mild or moderate dry eye, and six times a day for eyes with severe dry eye, and tear production was assessed at 2 weeks and at 3 months. Results: At two weeks, among the eyes treated with Vidisic gel, Schirmer test score improved from 12 mm to 13 mm (p > 0.05) for eyes with mild dry eye, from 6.5 mm to 8.4 mm for eyes with moderate dry eye, and from 3.1 mm to 6.3 mm for eyes with severe dry eye. In addition, among the eyes treated with teas substitutes, Schirmer test score improved from 11 mm to 13 mm for eyes with mild dry eye, from 6.1 mm to 8.1 mm for eyes with moderate dry eye, and from 2.6 mm to 4.4 mm for eyes with severe dry eye (p < 0.05). At three months, patients who were taking their medication as per schedule had approximately the same scores as at two weeks, whereas those who discontinued taking their medication or were taking it irregularly had approximately the same scores as at baseline. Conclusion: Our findings highlight the necessity of continuous tear substitute treatment for patients with DED and corneal and conjunctival cicatrization secondary to severe burns to the eye [ABSTRACT FROM AUTHOR]

The general anesthesia or sedation reduces both the tear production and the stability of tear film that protect corneal surface, predisposing itself to the exposure keratopathy. The aim of the present study was to evaluate the effects of intramuscular dexmedetomidine (DEX) on canine tear production, measured by standardized Schirmer Tear Test 1 (STT-1) strips, for the 8 h following sedation, in dogs. A significant effect of time on canine tear production was found, highlighting that dexmedetomidine sedative protocol significantly affects tear production in dogs. It is recommended to treat the canine eyes with tear substitutes to protect ocular surface health and the welfare of the dogs. The ocular lubrication should be performed during and up to 12 h after sedation. The present report could provide preliminary information to better understand the effect of DEX on the tear film dynamics. Tear film provides lubrication and protection to the ocular surface. The sedation reduces tear production, often leading to perioperative exposure keratopathy. The aim of the present study was to report the effects of intramuscular dexmedetomidine on canine tear production, measured by STT-1, for an experimental period of 8 h after sedation. Ten dogs who underwent sedation for routine radiologic assessment were recruited for the study. In all animals, tear production in right and left eyes was measured 15 min before sedation (T0: basal values) and 20 min (T20), 1 h (T1), 2 h (T2), 4 h (T4) and 8 h (T8) after drug administration. Analysis of variance and post hoc Bonferroni test (p < 0.05) were performed. A significant effect of time on canine tear production was found. The tear production returned to basal values at T8. So, it is recommended to treat the canine eyes with tear substitutes during and up to 12 h after sedation. [ABSTRACT FROM AUTHOR]

Abstract Background Dry eye disease (DED) is a prevalent complication of diabetes and presents as reduced tear production and/or increased corneal surface sensitivity often with secondary ocular surface changes. This study examined the safety and efficacy of a proprietary new eye drop formulation for topical treatment of DED. Methods Type 1 diabetes (T1D) was established in male Sprague-Dawley rats to study the efficacy and safety of the investigational compound that contained 20 μg/ml of naltrexone (NTX). Tear production was measured by the Schirmer’s 1 test, and ocular surface sensitivity was measured using an aesthesiometer. Diabetic rats received twice daily applications of a single drop (~ 0.02 ml) of the proprietary formulation (NTX-001) or vehicle onto one eye. For comparison, some diabetic rats received eye drops containing NTX in sterile Vigamox®. Safety was monitored by assessment of ocular histopathology in naïve male rats and naïve male rabbits receiving twice daily treatment of two drops for 30 days. Results Dry eye in T1D rats was reversed within hours of a single treatment of NTX-001, and over a period of 10 days NTX-001 restored corneal sensitivity and reversed dry eye relative to values measured in diabetic rats receiving vehicle. In comparison to NTX dissolved in Vigamox®, the proprietary NTX-001 was more effective at reversing dry eye. Safety studies in naïve rats and rabbits revealed no visible ocular pathology after 30 days of treatment. Conclusions An investigational new eye drop containing 20 μg/ml NTX effectively reversed tear film deficits and restored corneal surface sensitivity in diabetic animals without causing toxic side effects.