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African black-footed cats (Felis nigripes) are endangered wild felids. One male and full-sibling female African black-footed cat developed vision deficits and mydriasis as early as 3 months of age. The diagnosis of early-onset progressive retinal atrophy (PRA) was supported by reduced direct and consensual pupillary light reflexes, phenotypic presence of retinal degeneration, and a non-recordable electroretinogram with negligible amplitudes in both eyes. Whole genome sequencing, conducted on two unaffected parents and one affected offspring was compared to a variant database from 51 domestic cats and a Pallas cat, revealed 50 candidate variants that segregated concordantly with the PRA phenotype. Testing in additional affected cats confirmed that cats homozygous for a 2 base pair (bp) deletion within IQ calmodulin-binding motif-containing protein-1 (IQCB1), the gene that encodes for nephrocystin-5 (NPHP5), had vision loss. The variant segregated concordantly in other related individuals within the pedigree supporting the identification of a recessively inherited early-onset feline PRA. Analysis of the black-footed cat studbook suggests additional captive cats are at risk. Genetic testing for IQCB1 and avoidance of matings between carriers should be added to the species survival plan for captive management.

Dry eye syndrome (DES) is a commonly encountered ophthalmological disease, with a relatively high incidence, and expects an effective treatment method. Acupuncture-moxibustion therapy promotes tear production of lacrimal gland without causing a trauma, and thus has a great advantage in treating DES. Through literature analysis, this article summarized the research progress in both clinical practice and mechanism of acupuncture-moxibustion in treating DES during the recent 10 years, for providing valuable references for the application of acupuncture-moxibustion for DES.

Dry eye is a multifactorial disease of the tears and ocular surface that results in symptoms of discomfort, visual disturbance, and tear film instability, with potential damage to the ocular surface. The two main causes are reduced production of aqueous tears and increased evaporation of tears. The evaporative form of dry eye results in ocular surface irritation with a secondary increase in tear production; this presents to the examiner and patient as a wet eye or epiphora. Knowledge and understanding of the basic pathologies and differential diagnoses of dry eye disease are essential to differentiate this very common form of dry eye from disorders of the lacrimal drainage system and to initiate adequate management.

The successful development of a therapeutic agent targeting treatment of dry eye syndrome necessitates the demonstration of drug efficacy for both sign and symptom endpoints. As numerous therapeutic strategies incorporate a secretagogue function into their overall mechanism of action, the quantitative assessment of tear production serves as a logical endpoint to anchor “sign” efficacy. Although several methods including the Schirmer, the phenol red thread and tear clearance tests exist, their utility in clinical evaluations of novel therapeutics is unclear. The purpose of this review is to summarize findings and conclusions describing the performance of each of these tests so as to gain insight into which, if any, is most applicable for use in discovering new dry eye therapeutics.

The aim of this study was to evaluate the effect of linoleic acid (LA) and gamma-linolenic acid (GLA), both precursors of PGE(1), on tear production, tear fluorescein clearance and on the ocular surface after photorefractive keratectomy (PRK).Sixty subjects (age 25+/-10 years; refractive error -3+/-2 diopters (spherical equivalent), mean +/- standard deviation) undergoing PRK were enrolled. The inclusion criteria were: Schirmer 1 test10 mm/5 min, no corneal fluorescein staining, low irritation symptoms (questionnaire score5), standardised visual scale (to evaluate tear fluorescein clearance) score3. Patients were randomly divided into two groups. One group of 31 subjects was treated once daily orally with tablets containing LA (28.5 mg) and GLA (15.1 mg) (from 3 days before PRK to 1 month after PRK). The control group (29 subjects) underwent PRK and received no treatment with LA and GLA. A symptoms questionnaire, Schirmer 1 test and fluorescein clearance test (FCT) using the standardised visual scale were performed before starting therapy (T(0)) and 30 days after PRK (T(1)).All patients completed the study. The Schirmer 1 test varied from 16.3+/-6.9 (T(0)) to 17.6+/-7.2 (T(1)) for the treated group and from 18.3+/-6.2 (T(0)) to 15.7+/-7.4 (T(1)) for the untreated group ( P0.0001, two-tailed unpaired t-test). FCT was 1.9+/-0.6 at T(0) and 1.6+/-0.8 at T(1) for the treated group and 1.7+/-0.7 at T(0) and 2.0+/-0.9 at T(1) for the untreated group ( P0.0001). The symptoms score was 4.7+/-1.9 at T(0) and 7.6+/-7.2 at T(1) for the treated group and 4.2+/-2.0 at T(0) and 10.1+/-7.6 at T(1) for the untreated group ( P0.05).Reduced corneal sensitivity has already been proved after PRK. This could be the main reason for a decrease in tear production and for a reduced blinking rate leading to delayed tear clearance. The oral precursors of PGE(1), LA and GLA, could be helpful in increasing tear production and clearance after PRK.

Diadenosine polyphosphates are naturally occurring substances that facilitate tear secretion. The occurrence of these dinucleotides in human tears has been established and quantified by an HPLC technique and phosphodiesterase treatment. The concentration of these compounds found in tears was 2.0+/-2.2 nM for diadenosine triphosphate (Ap3A), 108.0+/-18.3 nM for diadenosine tetraphosphate (Ap4A) and 37.0+/-6.2 nM for diadenosine pentaphosphate (Ap5A). When subjects were treated with topical ocular anaesthesia, the concentrations of Ap3A, Ap4A and Ap5A changed to 1.5+/-1.7 nM, 189.3+/-19.5 nM and 112.6+/-12.3 nM, respectively. Ap4A and Ap5A increased tear secretion in rabbits, the effect presenting an EC50 value of 19.0+/-1.2 ng/microl and 11.4+/-1.3 ng/microl respectively. In conclusion, diadenosine polyphosphates are released from the corneal epithelium, they stimulate tear production and therefore they may be considered as physiological modulators of tear secretion.

The current study was undertaken to evaluate the effects of topical 0.5% timolol maleate on tear production in clinically normal horses. Fourteen horses free from clinically relevant ocular abnormalities were used in the study. The 14 horses were randomly assigned to a treatment or control group. The treatment group included seven horses that received 0.25 mL of 0.5% timolol maleate ophthalmic solution in a randomly chosen eye, and the opposite eye served as the untreated control. The control group included seven horses that received no topical medications during the study. Schirmer tear test was performed on both eyes of all horses 1 day prior to treatment (T0) and then at 1, 3, 7, and 14 days of treatment (T1, T3, T7, and T14). In the treatment group, the baseline (T0) Schirmer tear test (STT) values in the treated and non-treated eyes were 25.5 ± 3.8 and 26.1 ± 6.6, respectively. In the control group, baseline mean ± SD STTs were 21.4 ± 3.6 and 24.2 ± 4.4 in the right and left eyes, respectively. Baseline STTs between the treatment and control groups were not significantly different (P ≥ 0.97). There was no statistically significant change in STT values throughout the study period in treatment and control groups (P ≥ 0.15). In Conclusion, twice daily topical application of 0.5% timolol maleate had no significant effect on tear secretion when administered over a 2-week period in clinically normal horses.

Das in wassriger Losung vorliegende Timolol maleat wird bereits wenige Minuten nach lokaler Applikation in den Bindehautsack von der Schleimhaut resorbiert. Aufgrund der kurzen Verweildauer der Medikation im Bindehautsack ist ein Erreichen der optimalen Konzentration in der Kornea und in der Vorderkammer kaum moglich. In dieser prospektiven Studie untersuchten wir die Wirkung von Timolol maleat 0,1% in einer Gel-Grundlage. 111 Patienten (36,9% mannlich, 63,1% weiblich, Alter 64,5 ± 14,9 Jahre) mit primarem Offenwinkelglaukom, okularer Hypertension oder Normotensionsglaukom wurden uber 3 Monate mit Timolol maleat Hydrogel 0,1% (TH-GEL) einmal taglich behandelt. Zusatzlich zum Intraokulardruck (IOD) wurden auch die Tranenproduktion mittels Schirmertest und Tranenaufrisszeit dokumentiert. Die Auswertung erfolgte mittels deskriptiver Statistik und die Signifikanz wurde mit Hilfe der Friedman, Wilcoxon und Wilcox Tests ermittelt. Der durchschnittliche IOD konnte durch TH-Gel bei Patienten mit antiglaukomatos (Beta-Blocker) vorbehandelten Augen um 13,93 ± 20,41% (p < 0,001) und bei den nicht vorbehandelten Augen um 24,9 ± 11,96% (p < 0,001) gesenkt werden. Die Tranenproduktion (Schirmertest) stieg bei vorbehandelten Augen um 23.69 ± 43,8% (p < 0,001) und bei nicht vorbehandelten Augen um 33,46 + 63,9% (p < 0,001) an. Die Tranenaufrisszeit verlangerte sich bei vorbehandelten Augen um 22 ± 51% (p < 0,001) und bei nicht vorbehandelten Augen um 11,7 ± 23% (p< 0,001) Timolol maleat Hydrogel 0,1% stellt eine neue und effiziente Form der lokalen Beta-Blocker-Applikation dar. Der Vorteil liegt in der einmal taglichen Gabe und der 0,1 %igen Konzentration. Vor allem fur Patienten mit Sikkasymptomatik stellt diese Gelzubereitung eine empfehlenswerte Alternative zur wassrigen Losung des Timolol dar. Liquid solution of timolol instilled into the cul-de-sac is brought to systemic circulation within few minutes. Due to the short drug contact time with the surface, it is not possible to get the maximum concentration of the applied drug in the anterior eye segment. In this prospective study we evaluated the efficacy and tolerance of a gel-forming solution of timolol maleat 0.1 %. 111 patients (36.9% male, 63.1% female, age 64.5 ± 14.9 years) with primary open angle glaucoma, ocular hypertension or normal tension glaucoma were treated with timolol maleat hydrogel 0,1% once daily over a period of 3 months. Intraocular pressure (IOP), tear production (Schirmers test) and break-up-time (BUT) were evaluated. Statistical evaluation was performed using descriptive statistics. Friedman, Wilcoxon and Wilcox tests were used to evaluate statistical differences. The average IOP was reduced by TH-Gel in patients with antiglaucomatous pretreatment (beta-blocker) by 13.93 ± 20.41% (p < 0.001) and in patients without any pretreatment by 24.9 ± 11.96% (p < 0.001). Schirmers test raised in pretreated patients by 23.69 ± 43.8% (p < 0.001) and in not treated eyes by 33.46 ± 63.9% (p < 0.001). BUT was prolonged by 22 + 51% (p < 0.001) in pretreated and by 11.7 ± 23% (p < 0.001) in not treated eyes. Timolol maleat hydrogel 0.1 % is a new and effective form of topical beta-blocker application. The advantage lies in the once-a-day application and the 0.1% concentration. The application of timolol in a gel form presents an alternative to the liquid solution, especially in patients with dry eye syndrome.

The objective of this study was to evaluate effects of intramuscularly administered chlorpromazine alone and chlorpromazine–morphine combination on Schirmer tear test (STT) results in clinically normal dogs. Fourteen dogs free of clinically relevant ocular abnormalities were used in this study. STTs were performed and the dogs were injected intramuscularly with chlorpromazine alone (group C) and chlorpromazine–morphine combination (group CM). STTs were repeated 15, 25, 60, and 120 mins later. Aqueous tear production in dogs, measured by STT, was significantly reduced in both treatment groups 60 and 120 min after injection of the drugs. The mean ± SD STTs for the baseline time for chlorpromazine alone (group C) and chlorpromazine–morphine (group CM) were 19.4 ± 4.4 and 15.7 ± 4.0 wetting per minute, respectively. For group C, the subsequent mean ± SD STT levels were 18.78 ± 2.49 (15 min), 16.35 ± 4.79 (25 min), 13.71 ± 4.66 (60 min), and 14.14 ± 4.42 (120 min). For the CM group, the subsequent mean ± SD STT levels were 13.50 ± 6.09 (15 min), 11.57 ± 5.29 (25 min), 10.00 ± 4.16 (60 min), and 9.42 ± 5.23 (120 min). In conclusion, a single intramuscular dose of chlorpromazine alone or chlorpromazine–morphine combination significantly reduces tear production rates as measured by the STT in normal dogs.

Dacryocystography has been widely used in the assessment of the nasolacrimal duct system, particularly in patients with epiphora. The site of obstruction and presence of fistulas, tumor, diverticula, or calculi can be delineated so that therapy can be accurately planned. The water-soluble agent iohexol is currently widely used in nervous and vascular lesions in diagnostic radiology and also employed in dacryocystography. The aim of this study was to investigate the effects of iohexol on tear production and normal fluctuations of Schirmer tear test (STT) values in donkeys. The STT of ten normal donkeys were determined, which were done pre- and post-treatment of iohexol during dacryocystography. Schirmer tear test was performed at 0 h, 2 h, and 2 weeks pre- and post-dacryocystography with iohexol. All donkeys were housed outdoors throughout the study. There were no significant differences in tear production before and after administration of iohexol. The slight fluctuations in STT may be as a result of individual and/or environmental changes. Iohexol did not change STT values of the donkeys in this study.

Tear production was measured by means of the fine-cotton-thread method in rats. Sedation with hypnorm had no pharmacological effect on normal tear production. Daily oral administration of atropine which was comparable with the dose used for human adults on a drug-to-weight basis, resulted in a 60-percent reduction of tearing. Tearing returned to base-line levels after withdrawal of atropine.

The ocular surface is altered in kerato-conjunctivitis sicca, a disorder of aqueous tear production. Many of the factors leading to these surface changes are now more clearly understood and are discussed in this paper.