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OBJECTIVE Leopard Geckos (Eublepharis macularius) are popular pets and can be affected by a range of ocular disorders. Our objective was to report ocular findings in a group of healthy captive leopard geckos and to establish reference ranges for commonly performed ocular diagnostic tests. ANIMALS STUDIED Twenty-six healthy male geckos aged 1 year old (n = 4) and >2 years old (n = 22). PROCEDURES All animals underwent ophthalmic examination, corneal esthesiometry, modified Schirmer tear test (mSTT), rebound tonometry, conjunctival bacterial aerobic and fungal culture, and measurement of ocular dimensions. Student's t test was used to compare values of corneal esthesiometry, tonometry and mSTT between groups. Multiple correlations were assessed by Pearson correlation coefficient. RESULTS All animals had a normal ocular examination. Tear production as measured with a mSTT (mean ± SD) technique was 3.1 ± 1.3 mm/min and tonometry values (mean ± SD) were 8.2 ± 1.7 mm Hg. Corneal touch threshold (median, range) was 4.4 cm, 2.5-5.0. Younger animals had a significantly increased corneal sensitivity compared to older animals (P = .0383). Results of culture showed no growth for fungal organism in any animals. Conjunctival bacterial isolation rates were low, with only 7/26 samples positive for nine bacterial species. CONCLUSIONS Leopard geckos are amenable to ophthalmic examination and ocular diagnostic database testing with minimal manual restraint.

OBJECTIVE To assess the response to topical and/or systemic pilocarpine in dogs with neurogenic dry eye. METHOD Medical records of dogs diagnosed with dry eye between 2015 and 2018 were reviewed. Cases were excluded if STT values were decreased bilaterally, if dogs were lost to follow-up, or if surgical measures (parotid duct transposition) were undertaken within thirty days of presentation. Dogs were on treatment with topical pilocarpine (0.1%, every 6 hours) and/or oral pilocarpine (starting dose 2%, one drop per 10 kg every twelve hours). RESULTS Eleven cases were included in the study, seven females and four males with mean age of 10 years. Seven cases had xeromycteria, two cases had facial nerve paralysis, and one case had Horner's syndrome. Seven cases (63.6%) had successful outcome following pilocarpine treatment, return to normal STT (15-25mm/minute), in an average of 24 ± 5.1 days. Of these cases, five had both systemic and topical treatment, one had just topical treatment, and one had just systemic treatment. The average time to normal tear production on treatment with topical pilocarpine ± systemic was 23 days (range 9-48 days). The number of systemic drops until a positive response varied between individuals from 0.8drops/10kg to 7drops/10kg. CONCLUSION Pilocarpine treatment (topical ± systemic) is an effective therapy for unilateral dry eye disease in cases suspected to be neurogenic in origin. Most cases responded within 30 days. Side effects included topical irritation to the ophthalmic solution and systemic effects from oral pilocarpine, such as diarrhea and regurgitation.

OBJECTIVE: To evaluate the tear production, intraocular pressure, and central corneal thickness in healthy white‐tailed deer (Odocoileus virginianus) and assess for seasonal variability. ANIMALS STUDIED: Nineteen healthy fawns (3‐10 days old) and 8 healthy adult white‐tailed deer (164‐280 days old) were studied. PROCEDURES: All fawns were manually restrained for the study, while adult animals were immobilized with an intramuscular injection of combined xylazine (2.2 mg/kg), tiletamine (1 mg/kg), and zolazepam (1 mg/kg). Tear production (STT‐1) was evaluated in both eyes of all fawns. Intraocular pressure (applanation and rebound tonometry) and central corneal thickness (ultrasound pachymetry) were determined in both eyes of all fawns and adult deer. RESULTS: Mean ± SD tear production in fawns was 12.32 ± 4.46 mm/min. Mean ± SD IOP values in the fawns were 16.21 ± 4.97 mm Hg (TonoPen®) and 14.05 ± 5.03 mm Hg (TonoVet®). In adult deer, mean ± SD IOP values were 15.57 ± 2.88 mm Hg with TonoPen® and 12.87 ± 2.57 with TonoVet®, and TonoPen® significantly overestimated the IOP, compared to TonoVet® (P

Purpose To evaluate the effect of twice daily aqueous 0.02% sirolimus drops on tear production in normal dogs and dogs with refractory keratoconjunctivitis sicca (KCS). Methods Two groups of dogs were studied. Ten normal dogs with no signs of ocular disease were administered topical 0.02% sirolimus ophthalmic solution in right eye, and a vehicle control in the left eye twice daily for 4 weeks. Complete ophthalmic examinations, including Schirmer tear test were performed weekly. Eighteen dogs with refractory KCS were randomly assigned to receive 0.02% sirolumus ophthalmic solution or 0.02% tacrolimus ophthalmic solution twice daily. Complete ophthalmic examinations were was performed at 2 and 6 weeks following treatment. Results Tear production in the sirolimus-treated eyes of normal dogs was greater when compared to vehicle controls with a mean difference over all time points of 3.46 mm (95% CI 1.17, 5.75; P = 0.006). After 4 weeks of treatment, the mean difference was 5 mm (95% CI 1.95, 8.05; P = 0.002). In dogs with refractory dry eye, 37.5% of eyes treated with sirolimus exhibited increased tear production >4 mm/min after 6 weeks of treatment, compared to 20% of eyes receiving tacrolimus (P = 0.433). One normal dog experienced topical irritation to both sirolimus and vehicle-treatment. Side effects were not reported in any treated eyes with chronic KCS. Conclusion Topical 0.02% sirolimus might be an alternative treatment for canine patients with keratoconjunctivits sicca. The drug appears safe when applied topically in an aqueous suspension for up to 6 weeks. While initial results are promising, further studies are warranted.

Objective The purpose of this study was to establish the normal values of strip meniscometry (SM) as a lacrimal function test and to compare the results with Schirmer tear test I (STT I) in dogs, cats, and rabbits. Animals studied Sixty healthy adult dogs from twelve different breeds (120 eyes), twenty adult healthy domestic shorthair cats (40 eyes) and eighteen adult healthy New Zealand white rabbits (36 eyes) were used in this study. Procedures Lacrimal function was tested by SM tube in all animals. After 24 h at the same time of day, tear production was measured using STT I. Results Mean SM and STT I values for all of the dogs, cats, and rabbits were 9.66 ± 2.15 mm/5 s and 15.10 ± 3.06 mm/min; 10.50 ± 0.7 mm/5 s and 11.00 ± 1.41 mm/min; 4.72 ± 1.20 mm/5 s and 4.22 ± 2.47 mm/min, respectively. There was a correlation (r = 0.281; P = 0.018) between SM and STT I values in dogs, but no correlation was observed in cats and rabbits (P = 0.61, P = 0.06). No correlation was found between age of animals and obtained SM values in each species (P > 0.29). Sex had no effect on SM values in each species (P > 0.08). Conclusions The result of this study provided the normal clinical values of strip meniscometry as lacrimal function test in three species.

Background Past studies have shown that 5-mm Schirmer tear tests (STTs) are difficult to interpret in guinea pigs. Modified 2.5-mm STT strips are more adequate for measuring the small volume of tear production in these animals. The aim of this study was to establish reference values for the modified 2.5-mm STT strips. Methods Modified STT measurements were performed in random order in both eyes of 50 guinea pig patients. The wetting of the strip was noted at 30 seconds and at 1 minute. Results The mean±sd STT values for both eyes were 7.58±3.19 mm at 30 seconds and 10.42±3.92 mm at 60 seconds. The median was 8 mm at 30 seconds and 10 mm at 60 seconds for both eyes. Animals under one year of age had lower STT values. STT values at 30 and 60 seconds can both be used. Both eyes should be measured when possible. Conclusion The authors recommend values above 8 mm at 30 seconds and 10 mm at 60 seconds to be considered normal when using a 2.5-mm STT strip. There are ambiguous areas at 5–8 mm and 6–10 mm. If in these ranges the results should be combined with clinical signs and judgement.

Keratoconjunctivitis sicca (KCS) is a relatively common condition affecting dogs worldwide.1-3 KCS is characterised by a deficiency in the production of the aqueous portion of the tear film, leading to conjunctival hyperaemia, bacterial overgrowth, ocular discharge, corneal vascularisation, corneal pigmentation, ocular pain and loss of vision.4-6 The primary cause of KCS is immune-mediated, but many other causes have also been reported, including congenital, metabolic, infectious, drug-induced, neurogenic, radiation, iatrogenic and idiopathic.7 The diagnosis of KCS is based on the presence of consistent clinical signs and measurement of decreased aqueous tear production using the Schirmer tear test (STT).8 It is largely accepted that an STT value greater than 15 mm/minute is considered normal for dogs, 11 to 14 mm/minute indicates subclinical KCS, 6 to 10 mm/minute indicates mild KCS and 5 mm/minute or less indicates severe KCS. However, several authors have criticised the STT’s variable sensitivity and reproducibility for diagnosing mild KCS.9,10 Due to the variability of STT measurements, a definitive diagnosis for mild cases of KCS may be difficult with the STT alone. As such, there is currently much interest in alternative measures for the diagnosis of KCS. A small number of previous studies …

Objectives The purpose of this study was to establish a reference value of tear production and intraocular pressure in clinically normal ducks and geese. Animal Studied The study population consisted of forty-eight ducks (24 males and 24 females) and fifty-two geese (26 males and 26 females). Procedures Birds were gently physically restrained in dorsoventral position without any pressure to the head and neck. Tear secretion and intraocular pressure were measured using 5-mm-wide Schirmer tear test strips and TonoVet® rebound tonometer, respectively. Results Overall mean ± 2SD STT and IOP values of all eyes were 6.2 ± 2.2 mm/min and 10.2 ± 2.2 mmHg, respectively, for the ducks; 5.5 ± 2.6 mm/min and 9.1 ± 2.0 mmHg, respectively, for the geese. There was no statistically significant difference in IOP between left eye and right eye or between males and females in ducks (P = 0.56, P = 0.63) and geese (P = 0.23, P = 0.22). Analysis of variance revealed that there were no significant differences in the STT and IOP between the breeds in ducks (P = 0.49, P = 0.68) and geese (P = 0.14, P = 0.26). Conclusions Results of this study may be beneficial for the diagnosis and therapeutic monitoring of ducks and geese affected with Keratoconjunctivitis sicca, glaucoma, and uveitis.

Objective To report ocular diagnostic test parameters and normal conjunctival bacterial flora in captive black-tailed prairie dogs. Animals studied Seventeen black-tailed prairie dogs, ranging in age from approximately 4–6 months to 4.5 years. Eleven males came from a zoo collection and 6 females from a wildlife rehabilitation center. Procedures Complete ocular examination was performed under isoflurane anesthesia. Tear and intraocular pressure (IOP) measurements were performed on both (n = 34) eyes of 17 prairie dogs. Phenol red thread test (PRTT) was performed first, and a modified Schirmer tear test I (mSTTI) was performed 10 min later. Indirect rebound tonometry was performed using the TonoVet®. Attempts to obtain intraocular pressure measurements using an applanation tonometry instrument were unsuccessful. Conjunctival swab samples (n = 17) were taken from both eyes of each prairie dog and pooled. Results The most common ocular abnormality was acquired eyelid margin defects, present in seven eyes of six prairie dogs (35.3%). Mean ± SD tear production was 13.6 ± 7.8 mm/15 s (range, 3–30) for PRTT and 1.2 ± 0.9 mm/min (range, 0–4) for mSTTI. Mean ± SD IOP was 7.7 ± 2.2 mmHg (range, 3–11.4). A Staphylococcus xylosus (7/17; 41.2%) organism and a hemolytic Staphylococcus species (5/17; 29.4%) were most commonly isolated from the prairie dog conjunctival sac. Conclusions There was a moderate prevalence of acquired peri-ocular lesions in this group of captive black-tailed prairie dogs. While widely variable, results of tear test and intraocular pressure measurements are reported. Staphylococcus was the most commonly isolated bacterial genus.

Objective The aim of this study was to investigate the development of aqueous tear production and intraocular pressure in healthy canine neonates between 2 and 12 weeks of age. Animals One litter, consisting of 8 healthy Beagle dogs—four males and four females—was used. Procedures Between the age of 2 and 12 weeks, tear production and intraocular pressure were measured weekly in both eyes. Tear production was measured by Schirmer tear test, before (STT1) and after (STT2) topical anesthesia and drying of the conjunctival sac. Intraocular pressure (IOP) was measured using a rebound tonometer. As no significant differences existed between left and right eye measurements (STT1, STT2, and IOP) at all time points, only right eye measurements were further analyzed. Results STT1, STT2, and IOP values increased significantly until the age of 9 weeks for STT1, until the age of 10 weeks for STT2, and until the age of 6 weeks and again between 10 and 11 weeks of age for IOP. IOP decreased significantly between 11 and 12 weeks of age. There were no significant differences in STT1, STT2, and IOP between males and females, except for IOP at 10 and 12 weeks of age. No significant correlation was demonstrated between body weight and STT1 or STT2. Conclusions STT1, STT2, and IOP values increased significantly in the first weeks after birth. The results of this study indicate that separate reference values for tear production and intraocular pressure need to be established for neonatal dogs.

Objective To evaluate endodontic paper point tear test (PPTT) in rabbits and compare changes in corneal touch threshold (CTT) induced by Schirmer tear test (STT) and PPTT. Normal corneal sensitivity recovery time after both tear tests was also measured. Also, mean PPTT and STT values were obtained. Methods Tear production of 20 eyes, from 10 rabbits, was evaluated using STT and the PPTT. Central corneal touch threshold was measured by a Cochet-Bonnet esthesiometer before any tear test was performed (zero time), immediately after the test (1 min), and consecutively at 6, 11, 16, and 26 min. Tests were conducted on three consecutive days: Day 1 – control condition, no tear tests performed only the CTT; Day 2 – CTT before and after PPTT; and Day 3 – CTT before and after STT. CTT values were compared using repeated measures ANOVA. Results Corneal touch threshold was significantly increased for at least 16 min after STT, indicating STT causes corneal discomfort. No difference was found between CTT following PPTT and controls, indicating PPTT caused minimal corneal discomfort. The mean (±SD) value for STT was 5.2 ± 1.0 mm/min and for PPTT was 13.8 ± 1.5 mm/min. Discussion The aqueous fraction of rabbit's tears can be successfully measured by PPTT. This report established reference values for PPTT in rabbits. Additionally, the absence of a significant difference in CTT after PPTT compared with controls shows that PPTT is well tolerated by rabbits. Considering the improved comfort (compared with STT), accuracy, and low cost, PPTT is a bona fide method of measuring aqueous tear production in rabbits.

Purpose The aim of this study was to establish normal ophthalmic parameters for select diagnostic tests in red-footed tortoises (Chelonoides carbonaria). A total of 52 animals, approximately 20–30 years old, were studied. Method Ophthalmic diagnostic tests included culturing of the normal conjunctival bacterial flora in summer and winter, evaluation of tear production using Schirmer tear test (STT) and endodontic absorbent paper point tear test in two different environmental temperatures (EAPPTT-1 at 32 °C and EAPPTT-2 at 18 °C), cytology of conjunctival cells, B-mode ultrasonography, measurement of palpebral fissure length (PFL), and applanation tonometry (in two different positions). Results In both seasons, Gram-positive bacteria were predominant. Median (± IQR/2) STT was 12.0 ± 3.5 mm/min, EAPPTT-1 was 15.9 ± 0.7 mm/15 s, and EAPPTT-2 was 15.4 ± 0.4 mm/min (OD) and 17.8 ± 1.0 mm/min (OS). Anterior chamber depth was 1.0 ± 0.1 mm, lens axial length was 2.3 ± 0.1 mm, vitreous chamber depth was 4.3 ± 0.2 mm, and axial globe length was 7.7 ± 0.3 mm. PFL was 11.7 ± 1.7 mm. Intraocular pressure was 11.5 ± 2.8 mmHg for males and 14.0 ± 3.5 mmHg for females (dorsoventral position) and 18.0 ± 3.2 mmHg for males and 24.1 ± 3.0 mmHg for females (ventrodorsal position with inclination of 45°). The ophthalmic parameters reported here can aid in the diagnosis of eye diseases in red-footed tortoises (Chelonoides carbonaria).

In the dilemma discussed in the June issue of In Practice, David Williams described a scenario where you are presented with a puppy that has abnormal eye discharge which, on inspection with the Schirmer tear test, is confirmed as dry eye. The recommended treatment is topical cyclosporine, which is likely to restore tear production while alleviating the discomfort that is clearly a welfare issue for the animal. Without such treatment the quality-of-life for the puppy reduces dramatically due to chronic corneal pain. However, the owner is unable to afford this licensed treatment. You remember the days before cyclosporine ointment was licensed, when the oral formulation of cyclosporine used for atopic dermatitis was diluted in corn oil and worked perfectly well. (IP, June 2019, vol 41, pp 230-231). What do you do?

In the dilemma discussed in the June issue of In Practice, David Williams described a scenario where you are presented with a puppy that has abnormal eye discharge which, on inspection with the Schirmer tear test, is confirmed as dry eye. The recommended treatment is topical cyclosporine, which is likely to restore tear production while alleviating the discomfort that is clearly a welfare issue for the animal. Without such treatment the quality-of-life for the puppy reduces dramatically due to chronic corneal pain. However, the owner is unable to afford this licensed treatment. You remember the days before cyclosporine ointment was licensed, when the oral formulation of cyclosporine used for atopic dermatitis was diluted in corn oil and worked perfectly well. (IP, June 2019, vol 41, pp 230-231). What do you do?

The purpose of this study was to evaluate the values of Schirmer tear test (STT) and determine effects of age, life stage, sex, breed and neuter status on tear production in healthy cats.Three hundred and forty-three domestic shorthair (DSH) and Persian cats, 50 days through 18 years old, were examined in this study. STT I was used to measure tear production in both eyes of each cat.A mean STT 14.9±4.8 mm/min was calculated for the eyes of all cats. There was a significant difference between STT values in kittens (≤6 months old) and cats of other age groups (P0.001). A substantial number of cats with clinically normal eyes had STT values less than 10 mm/min. No significant difference was found between males (14.7±5.0 mm/min) and females (15.1±4.5 mm/min) in STT values (P=0.46). Significant differences were found between entire (14.4±4.2 mm/min) and neutered (16.2±4.1 mm/min) cats (P=0.001), and between STT values of DSH (14.6±5.0 mm/min) and Persian (16.5±3.1 mm/min) cats in the study population (P=0.001).This study documents the average STT values for a sizeable feline population demonstrating that, in contradistinction to the situation in dogs, a number of cats with clinically normal eyes have STT values below 10 mm/min.

Objective To determine the effect of topical naltrexone 0.3% on tear production, corneal sensitivity, and tear film stability in normal brachycephalic dogs. Animals Studied Twenty-two normal brachycephalic dogs. Procedures Measurements of tear production (Schirmer tear test I and II), intraocular pressure (IOP), central corneal sensitivity (CS), and tear film breakup time (TFBUT) were collected at time 0, 1, and 24 h after administration of either naltrexone (NTX) 0.3% or placebo (SV). Naltrexone or SV was then administered once daily for 1 week, and the above measurements were repeated at 7 days, then again 7 days after discontinuing medication. Owners scored the degree of comfort, redness, rubbing, squinting, and tearing. Serum was collected at time 0, 1, 24 h, and 7 days to determine systemic concentrations. Results Owners reported no significant change in the degree of comfort, redness, rubbing, squinting, or tearing. Naltrexone was detected in serum of all treated dogs 1-h postadministration (average: 908 pg/mL, range: 319–1570 pg/mL) and in two dogs at the 1-week time point. Naltrexone was not detected at the 24-h time point. There was no significant effect of NTX on STT1, STT2, IOP, CS, or TFBUT. Conclusions Naltrexone 0.3% is well tolerated and safe when applied topically to the eye once daily. Naltrexone 0.3% did not show any significant effects on corneal parameters as measured in this study. At once, daily dosing NTX is systemically absorbed; however, the degree of systemic absorption is not likely to be clinically significant.

Objective – To determine the tear production in dogs admitted to an intensive care unit (ICU). Design – Prospective observational study from November 2010–September 2011. Setting – Private emergency and referral hospital. Animals – Thirty healthy control dogs and 30 dogs hospitalized in an ICU for treatment of systemic illness without previously diagnosed ophthalmic disorders and no recent history of anesthesia. Enrollment was based on availability of the ophthalmologist within 24 hours of admission to the ICU. Interventions–TearproductionwasmeasuredutilizingSchirmertearteststrips(STT)inhealthycontrolanimals as well as in hospitalized canine patients. All patients received an ophthalmic examination by a board-certified veterinary ophthalmologist within 24 hours of admission to the ICU. Lubrication with artificial tear gel every 2–4 hours as needed was implemented after STT was measured. Measurements and Main Results – Average tear productions in the control and canine ICU populations were 24.5 mm/min and 13.2 mm/min, respectively. This was found to be statistically significant (P < 0.001). Furthermore, there was a trend toward a decrease in tear production in patients with kidney disease and a trend toward normal tear production in patients with cardiac disease but the sample size was likely too small to enable detection of a statistically significant difference. Conclusions – This study demonstrates a decrease in tear production in canine ICU patients. While further study is warranted to determine how different diseases impact tear production, these finding support the implementation of frequent ocular lubrication in all ICU patients. (J Vet Emerg Crit Care 2013; 23(3): 274–279) doi: 10.1111/vec.12055

Purpose The ability of human newborns to produce tears has been a subject of controversy in the literature since the mid-20th century, and there has been considerable debate as to whether they are able to produce tears. Recently, it was established that total tear secretion (reflex + basal) in full-term infants is similar to those of adults whereas both reflex and basal tear production is reduced in premature babies. The objectives of this study were to assess whether newborn dogs have measurable aqueous tear production at the fourth week of life and to evaluate a modified Schirmer tear test (mSTT) as a useful method for measuring neonatal tear production in dogs. Methods Thirty four-week-old healthy puppies from six litters were evaluated. A control group was composed of 10 normal adult dogs. The mSTT strips were obtained by cutting a 5 mm-wide strip in half (making two 2.5 mm-wide strips). The mSTT1 was performed in puppies and adult dogs. Values were compared using t-tests. Results In neonates, the average value for the mSTT1 was 13.6 ± 3.07 (range = 7–19 mm/min), which was significantly lower in neonates than in adult dogs (23.25 ± 3.5, range = 17–30 mm/min, P

Objective: To report normal tear production of healthy adult black-tufted marmosets and propose a novel alternative for the measurement of the aqueous portion of tear production in animals with small eyes. Animal studied: Black-tufted marmosets (Callithrix penicillata). Procedures: Tear production of 19 animals was evaluated by the following methods: modified Schirmer’s I, phenol red thread and the novel use of standardized endodontic absorbent paper points. These methods and results were compared. Additionally, blink frequency and palpebral fissure length were measured. Results: Modified Schirmer’s test I, mean = −0.46 ± 3.41 mm/min; Phenol red thread, mean = 13.27 ± 5.41 mm/15 s.; Standardized endodontic paper points, size 30, mean = 9.32 ± 3.09 mm/min; Mean palpebral fissure length = 7.83 ± 0.72 mm. Blink frequency, mean = 20.27 ± 5.92/5 min. Conclusions: Normal parameters for blink frequency, palpebral fissure length and tear production measurement are presented. The palpebral fissure of black-tufted marmoset is very small and tear production is one of the lowest reported for all animal species. A novel and practical alternative for tear production measurement using standardized endodontic absorbent paper points is presented and is indicated for animals with small eyes.

Background Vitiligo is a common, acquired, pigmentary disorder characterized by the loss of melanocytes. In this study, we evaluated the ophthalmalogic abnomalies of patients with vitiligo with regard to tear functions. Methods The patients and control subjects underwent examinations via the Schirmer's test, tear film break-up time (BUT), and Rose Bengal staining. Results Schirmer test values in patients with vitiligo were lower than those in the control subjects, but the differences were not statistically significant (P = 0.200). In addition, the BUT values of patients with vitiligo were also significantly lower (P

Objective To determine effects of 14 days of oral administration of trimethoprim-sulfamethoxazole on aqueous tear production in clinically normal Syrian hamsters. Animal studied Fifteen healthy adult Syrian hamsters. Procedure Baseline phenol red thread test (PRTT) values were recorded 1 day prior to treatment. Eight hamsters in treated group received 15 mg/kg trimethoprim-sulfamethoxazole orally twice a day for 14 days. The remaining seven hamsters were used as untreated controls and received a placebo. All ophthalmic tests were performed without chemical restraint. PRTT values were evaluated in both eyes of all Syrian hamsters using a commercial PRTT strip of a single lot number. Results The mean ± SD baseline PRTT values for treatment group and control group were 7.25 ± 1.3 mm/15 s and 5.42 ± 1.13 mm/15 s, respectively. After 14 days of drug administration, the mean ± SD PRTT values for treatment group and control group were 5.62 ± 1.5 and 5.64 ± 0.74, respectively. Significant decreases in the PRTT values, compared with baseline values, were observed in the treatment group on day 15 (P = 0.042). Conclusions Trimethoprim-sulfamethoxazole decreased tear production in the hamster in this study.

Objective To establish a baseline range or average for tear production in normal juvenile dogs and evaluate the effects of age, weight, and gender on Schirmer tear test (STT) in juvenile dogs. Materials and methods Healthy puppies of various breeds

Objective This study was designed to assess the daily rhythm of tear production in clinically healthy horses, to compare left eye and right eye, and to evaluate the influence of time and gender. Animal studied For our study 18 horses (nine female and nine male) were subjected to three different light/dark (L/D) schedules: 12/12 L/D cycles, constant light (24/0 L/D) and constant darkness (0/24 L/D). Procedures In all subjects Schirmer tear tests were performed at 4-h intervals over a 24-h period. Results A circadian rhythm of tear production was found during the 12/12 L/D period and during constant darkness. Also our results showed a statistical significant difference comparing left eye and right eye, and between gender. Conclusions Our findings would suggest that the time of tear evaluation is significant in the diagnosis of tear film disorders, and that the difference between the two eyes and the two genders should be taken into consideration during the ophthalmic exam.

Objective To determine whether there is an association between evisceration with intraocular prosthesis placement via a dorsal scleral approach and decreased corneal sensitivity or aqueous tear production in dogs. Design Prospective study. Procedure Twenty-one dogs scheduled to undergo unilateral evisceration with intraocular prosthesis, and with a normal normotensive contralateral eye, based on slit-lamp biomicroscopy, indirect ophthalmoscopy and applanation tonometry, were included in the study. Central corneal sensitivity was measured with a Cochet-Bonnet esthesiometer prior to (week 0) and 2, 7, 14 and 28 weeks following surgery. Other pre- and postoperative data collected were Schirmer's tear test (STT I), Schirmer's tear test with topical anesthesia (STT II), corneal fluorescein retention, and intraocular pressure (IOP; postoperative control eye only). Axial globe length was determined for both eyes. Scleral incision length in the surgery eye was also recorded. Results Corneal sensitivity was significantly lower in eyes undergoing evisceration with intraocular prosthesis than in control eyes both preoperatively and postoperatively at all time points. There was no significant difference between preoperative and postoperative corneal sensitivity within the two groups. There was no significant difference in STT I or STT II-values between control eyes and surgery eyes preoperatively. There was a significant difference between preoperative and 2-week postoperative STT I in the surgery eye. There was a significant difference between the preoperative and 28-week postoperative STT II in the surgery eye. The 28-week postoperative STT I-values differed significantly between control and surgery eyes. Corneal sensitivity tended to decrease with increased degree of buphthalmos or with increased scleral incision length, although neither relationship was statistically significant. Conclusions Eyes that have sustained chronically elevated intraocular pressure had decreased axial corneal sensitivity compared to normal eyes, which persisted even after intraocular pressure was reduced. The presence of buphthalmos appeared to be a factor in globes developing decreased corneal sensitivity. Evisceration via a dorsal scleral incision did not result in a significant further reduction in axial corneal sensitivity. A mild reduction in aqueous tear production occurred over time in globes following evisceration with intraocular prosthesis.

Objectives: Previous reports have suggested that hypothyroid and diabetic patients can be predisposed to keratoconjunctivitis sicca. This study aimed to measure tear production in dogs with diabetes, hypothyroidism and hyperadrenocorticism using the Schirmer tear test and to compare these results with Schirmer tear test values for a group of normal dogs. Methods: Schirmer tear tests were performed on 16 dogs with hyperadrenocorticism, 18 with diabetes and 12 with hypothyroidism together with 100 control dogs. Corneal sensitivity was also measured in 12 of the 18 diabetic dogs with a Cochet Bonnet aesthesiometer and compared with age- and breed-matched normal dogs. Results: Schirmer tear test values in dogs with hypothyroidism, hyperadrenocorticism and diabetes were 12·3±3·2, 14·0±4·0 and 12·3±5·3 mm/minutes, respectively. Schirmer tear test values were significantly lower than that for the control group (19·6±4·2 mm/minutes) in all dogs with an endocrinopathy. Only in two hypothyroid dogs and three diabetics, this was manifested as profound keratoconjunctivitis sicca with Schirmer tear test value lower than 5 mm/minutes. Diabetic dogs had significantly reduced corneal sensitivity compared with a matched set of control dogs. Clinical Significance: This study shows a significant reduction in tear production in animals with diabetes mellitus, hypothyroidism and hyperadrenocorticism. Further research is needed to elucidate the mechanisms by which this reduction in tear production occurs. Assessment of tear production should be undertaken in animals diagnosed with these endocrinopathies, as these animals may progress to clinical keratoconjunctivitis sicca.

Objective To develop a standard method for measuring tear production in large Psittaciformes using the phenol red thread (PRT) tear test. To establish mean PRT tear test values in clinically normal pet birds and to assess the reproducibility of the test. Animals Two geographically distinct populations of healthy, large Psittaciformes (pilot study and study population). Species groups include: cockatoo (17), macaw (22), Amazon (10), African gray (1), eclectus (1) and pionus (1). Procedure The PRT was placed under the upper eyelid and both eyelids were held closed throughout the test. The PRT tear test was repeated after 2 months in the pilot study and after approximately 5 min in the study population. Results The mean PRT tear test values for the pilot study were OD = 28.2 mm/15 s (± 6.3 mm), OS = 24.1 mm/15 s (± 6.6 mm) and OD = 25.4 mm/15 s (± 3.3 mm), OS = 25.5 mm/15 s (± 5.2 mm), for the first and second visits respectively. The mean PRT tear test value for the study population was: OD = 19.8 mm/15 s (± 4.3 mm), OS = 20.1 (± 3.9 mm) and OD = 20.0 mm/15 s (± 4.5 mm), OS = 19.1 mm/15 s (± 3.3 mm), for the first and second tests respectively. There was poor repeatability between tests. Conclusions and clinical relevance Results suggest that the PRT tear test is a practical method for measuring tear production in large Psittaciformes, although adaptations to the established diagnostic method are necessary to overcome some anatomical differences present in birds. Good reproducibility of the PRT tear test could not be demonstrated in a clinically normal population of birds but geographic location appears to significantly influence results.

Objective To evaluate effects of lacrimal punctal plugs positioned in either the upper, lower, or combination of upper and lower lacrimal canaliculi on plug retention and tolerance; tear production, as measured by the Schirmer tear test; and the dilution of fluorescein within the tear film in normal dogs. Material and methods Lacrimal punctal plugs were positioned in the lower, upper, or combination of lower and upper plugs in six laboratory-quality Beagles under topical anesthesia. Retention of plugs was evaluated daily from 8 to 23 days by visual inspection and slit-lamp biomicroscopy. Schirmer tear tests (STT 1 without topical anesthesia) were performed at 48-h intervals. Dilution of fluorescein was determined at 5- and 45-min post-fluorescein instillations once weekly. Results Lacrimal punctal plugs of 0.4 and 0.6 mm in diameter were retained for 14 (lower plugs: 100%) and 23 days (75%), and for the upper plugs at 8 days less often (75%), and were infrequently locally nonirritating. Combination of lower and upper plugs seemed to adversely affect retention of either plug. When loss of the plugs occurred, a next larger size plug was necessary suggesting some stretching of the lacrimal canaliculi occurred. Pre- and postplug placement STT results indicated no change with lower and combination lacrimal punctal plugs, but decreased levels following upper lacrimal punctal plugs. Tear fluorescein levels at 5 and 45 min in control eye (no punctum plugs) were 3.39% and 0.14%, respectively. With lower, upper, and the combination of lower and upper lacrimal puncta plugs, tear fluorescein levels at 45 min were higher than the controls (lower: 0.76%; upper: 0.45%, and combination 0.56%). Conclusion Lacrimal punctal silicone plugs are retained for 8–23 days in the lower, upper, and combined lower and upper canaliculi at high rates. Effects on STT levels appear limited. Fluorescein within the tear film persists longer with all different positioned lacrimal punctum plugs than in the control eyes.

OBJECTIVE To investigate the effect of 0.02% tacrolimus in aqueous suspension on tear production in dogs with keratoconjunctivitis sicca (KCS). Animals studied One hundred five dogs diagnosed with KCS [Schirmer tear test (STT) < or = 10 mm/min and clinical signs of dry eye]. Eyes with marginally decreased STT (11 < or = 15 mm/min) and clinical signs of dry eye were also evaluated. PROCEDURE The investigation was conducted in two parts: an initial efficacy study and a subsequent double blinded controlled study. In the efficacy study, the effect of topical tacrolimus (formerly FK-506) on tear production in dogs with primary KCS was evaluated. Dogs were divided into four categories: 1) 59 eyes (38 dogs) naive to tear stimulation therapy with initial STT < or = 10 mm/min; 2) 28 eyes (21 dogs) naive to tear stimulation therapy with initial STT 11 < or = 15 mm/min; 3) 30 eyes (15 dogs) maintained successfully on CsA therapy; 4) 47 eyes (24 dogs) unresponsive to CsA therapy. STT and clinical signs were evaluated prior to and after 6 to 8 weeks of twice daily tacrolimus administration. Tacrolimus was substituted for CsA therapy in categories 3 and 4. The controlled study compared the effect of topical tacrolimus in aqueous suspension to administration of the aqueous carrier alone on tear production in 20 dogs with primary KCS. RESULTS In the efficacy study, STT increased by 5 mm/min in 84.7%, 25.0%, 26.7% and 51.1% of eyes in categories 1, 2, 3 and 4 respectively after tacrolimus administration. Eighty-three percent of eyes with extremely low initial STT (< or = 2 mm/min), increased 5 mm/min after tacrolimus. In the controlled study, STT increased by 5 mm/min in 7/10 dogs (14/20 eyes) that received tacrolimus and in none of the 10 dogs that received aqueous carrier alone. Dogs receiving just the aqueous carrier were subsequently treated with tacrolimus, and STT increased 5 mm/min in 9 dogs (18/20 eyes) after administration. CONCLUSIONS Twice daily administration of 0.02% tacrolimus in aqueous suspension effectively increased tear production in dogs with KCS. Topical tacrolimus is a promising alternative to topical CsA for treatment of KCS and may be beneficial in patients with less than optimal response to topical CsA.

The objectives of this study were to observe the effects of trimethoprim-sulfadiazine on equine tear production and to determine normal fluctuations in Schirmer tear test (STT) values in horses. A randomized, placebo-controlled, blinded clinical trial measuring STT values in 15 horses over an 8-week period was performed. The treatment group (eight horses) received 30 mg/kg trimethoprim-sulfadiazine orally once a day and the control group (seven horses) received placebo (flour) at the same time. All horses were housed outdoors throughout the study. Schirmer tear test values were measured at 0, 2, 4, 6 and 8 weeks, and 4 weeks after discontinuation of treatment. There were no significant differences in tear production between the treated and control groups. Fluctuations in STT were observed and may result from individual and environmental variations. Trimethoprim-sulfadiazine did not decrease tear production in the horses in this study. Horses normally experience periodic fluctuations in STT values.

OBJECTIVE To evaluate the effect of a single dose of topical 1% tropicamide on tear production as measured by the Schirmer tear test (STT) in the normal dog and cat. MATERIAL AND METHODS Twenty-eight dogs and 32 cats received 50 micro l : l of 1% tropicamide in one eye and the opposite eye served as the control. STTs were performed immediately before instillation of tropicamide and then at 1, 4, 8 and 24 h post drug instillation. STT results were compared between the control and treated eyes at the different times. RESULTS Aqueous tear production in dogs, measured by STT, was not significantly reduced. The mean +/- SEM STTs for the baseline time for control and tropicamide-treated eyes were 19.9 +/- 0.8 and 20.3 +/- 0.8 mm wetting/min, respectively. For the control eyes, the subsequent mean +/- SEM STT levels were 20.3 +/- 0.9 (1 h), 21.1 +/- 0.8 (4 h), 20.1 +/- 0.9 (8 h), and 18.7 +/- 0.7 (24 h). For the tropicamide-treated eyes, the subsequent mean +/- SEM STT levels were 19.4 +/- 0.9 (1 h), 19.3 +/- 0.9 (4 h), 20.0 +/- 0.9 (8 h), and 18.4 +/- 0.8 (24 h). Aqueous tear production of both eyes was significantly reduced in cats at 1 h but returned to baseline by 4 h post tropicamide instillation. The mean +/- SEM STT levels for the baseline time in cats for control and tropicamide-treated eyes were 14.9 +/- 0.8 and 14.7 +/- 0.8 mm wetting/min, respectively. Subsequent mean +/- SEM STT levels for the control eyes were 6.4 +/- 1.1 (1 h), 11.9 +/- 1.0 (4 h), 13.9 +/- 0.8 (8 h), and 16.4 +/- 1.0 (24 h). For the tropicamide-treated eyes, the subsequent mean +/- SEM STT levels were 5.3 +/- 0.8 (1 h), 10.2 +/- 0.8 (4 h), 14.7 +/- 1.0 (8 h), and 16.6 +/- 1.0 (24 h). CONCLUSION Single dose 1% tropicamide does not significantly lower tear production rates, as measured by the STT, in normal dogs. However, in normal cats single doses of 1% tropicamide in one eye cause significant reductions in tear production of both eyes at 1 h that recovered to baseline levels by 4 h.

Purpose To determine the normal reference range for Schirmer tear test (STT) values in clinically normal llamas (Lama glama) Animals Nine captive llamas (Lama glama) (seven females and two males) were used in this study. Procedure Complete ophthalmic examinations were performed without chemical restraint. STT I values were evaluated in both eyes of all llamas using a commercial STT strip of a single lot number (Schirmer-Tranentest®, Germany). STT II value was also measured in both eyes of seven female llamas. Results No statistically significant differences among ages or between right and left eyes were found for any of the results. The mean ± SD STT I of 18 eyes of nine llamas was 17.3 ± 1.1 mm/min (Range 15–19 mm/min). The mean ± SD STT II of 14 eyes of seven llamas was 15.4 ± 1.7 mm/min (Range 12.5–17.5 mm/min). A paired samples t-test demonstrated that there was a significant difference between the STT I and II values (P = 0.001). Conclusion This study provides novel data for normal reference ranges of STT I and II values in healthy llamas. Results of this study may assist veterinarians in the diagnosis of ocular surface disease and syndromes affecting the tear film in these species.

Objective To evaluate the effect of acepromazine or xylazine on Schirmer tear test 1 results in clinically normal cats. Animals Sixteen healthy cross-breed cats. Procedure The animals were randomly divided into two groups of eight cats each. The first group was sedated with acepromazine alone (0.2 mg/kg) and the second group received only xylazine (2 mg/kg). All cats had Schirmer tear test (STT) readings taken prior to sedation and at 15 and 25 min postsedation. Results Sedation with acepromazine or xylazine in cats with normal pre-sedation STT 1 values caused a statistically significant decrease in mean values of tear production in both groups. In acepromazine group the mean ± SEM STT at T15 and T25 were 4.31 ± 0.98 (P

Objective To observe the effect of topical 1% tropicamide on equine tear production as measured by Schirmer I tear test. Materials and methods Fourteen adult horses received one drop of 1% tropicamide ophthalmic solution in one eye and the opposite eye served as the control. The tear production in both eyes was tested at 1, 2, 4, 6, and 24 h after 1% tropicamide administration. Results Measurements made 1 h after treatment revealed a significant reduction in Schirmer tear test values in tropicamide treated eyes (P = 0.002). The observed decrease in tear production was maintained up to 4 h after treatment (P = 0.002). Although tropicamide-induced decrease in STT values was observed in the treated eyes, the contralateral eyes did not show significant changes in Schirmer tear test results. Conclusion Single dose of topical 1% tropicamide resulted in statistically significant reduction in Schirmer tear test values in clinically normal horses.

Background This case report describes the treatment of three male owl monkeys (Aotus nancymaae) diagnosed with chronic dry eye with a topical cyclosporine product, Restasis®, approved for use in humans. These owl monkeys had ocular disease resulting from procedures performed at a biotechnology company. They were moved to the Center for Neotropical Primate Research and Resources at University of South Alabama to be incorporated into the breeding colony. Materials and methods Schirmer tear testing was performed initially and during the course of treatment to monitor efficacy of twice daily administered Restasis®. The goals of treatment were to reduce pain and/or distress and if possible to quantitatively increase tear production. Results and discussion All animals had improvements in conjunctival inflammation and had an increase in tear production.

Purpose To evaluate current diagnostic tests and make future recommendations. Methods An evidence-based review of procedures. Results MGD is a common symptomatic disorder leading to associated ocular surface disease including evaporative dry eye. A two stage diagnostic approach is recommended including an assessment of meibomian function based on lid morphology, gland mass, expressibility, lipid layer appearance and tear evaporation. A diagnosis of dry eye is based on measures of tear production and clearance, tear osmolarity, tear film stability and the presence of ocular surface changes revealed by tissue staining and inflammatory biomarkers. Quantification of MGD depends on grading meibum quality and expressibility. Newer, quantitative methods will make grading more accurate in the future and include quantitative meibomian expression, non-invasive meibography, confocal microscopy, video-interferometry and the use of inflammatory biomarkers. Meibomian gland dropout can be to monitor and stratify MGD in clinical trials. Conclusion A provisional severity rating of MGD and MGD-related disease has been proposed as a guide to the selection of treatment and the monitoring of disease progression.

The volume of tears in the eye depends on ihe rate of production and the rate of elimination by drainage and evaporation. A mechanism for the regulation of tear production mediated through changes in tear tonicity has been suggested. High evaporation of tears with a patent drainage system has been thought to be related to reduced tear volume, increased tonicily and an eventual stimulus to production. In this study no significant correlation was found between tear evaporation, measured by a modified evaporimeter system, and tear production, as measured by the turnover rate with a scanning fluorophotometer. This result suggests that regulation of tear production through the mechanism of tonicity change may not be the only, or principal, mechanism in the normal eye.

Editor, W e would like to thank Drs Lazar & Rothkoff (2009) for their interest in our recent article, which evaluated ocular surface changes in patients with familial Mediterranean fever (FMF) (Karalezli et al. 2009). We found that despite normal tear production, the ocular surface and tear-film functions of FMF patients differ from those of healthy individuals. We concluded that these changes might be related to the chronic inflammatory nature of FMF. Drs Lazar & Rothkoff stated that ocular surface changes in FMF patients might have resulted from the colchicine treament that they received. There are few case reports in the literature that report the delay of corneal wound healing in patients with FMF who are under colchicine treatment (Biedner et al. 1977; Alster et al. 1997; Leibovitch et al. 2003a, 2003b). However, there is no prospective randomized clinical study that evaluates the effect of colchicine on the ocular surface. Leibovitch et al. (2003a, 2003b) reported that very small quantities of colchicine were secreted in tears but they could not state whether the levels that were measured were in a toxic range. Further prospective randomized control-group studies are needed to confirm the effect of colchicine on the ocular surface and its correlation with the amount and duration of colchicine treatment.