Precorneal retention time of ocular lubricants measured with fluorophotometry in healthy dogs.

OBJECTIVE: Determine the precorneal retention time of five different ocular lubricants commonly used in dogs. ANIMALS STUDIED: Six healthy Beagle dogs (n = 12 eyes). PROCEDURES: Five ocular lubricants were studied: Artificial Tears Solution® (1.4% polyvinyl alcohol), I-Drop® Vet Plus (0.25% hyaluronate), Optixcare® Eye Lube Plus (0.25% hyaluronate), Systane® Ultra (0.4% polyethylene glycol 400 and 0.3% propylene glycol), and Artificial Tears Ointment® (mineral oil/white petrolatum). Each lubricant was mixed with 10% sodium fluorescein to achieve 1% fluorescein formulations. Following topical administration of 35 mg in each eye, tear fluid was collected with capillary tubes at selected times (0, 1, 5, 10, 20, 30, 40, 50, 60, 90, 120, 180 min) and fluorescein concentrations were measured with a computerized scanning ocular fluorophotometer. RESULTS: Tear fluorescence was significantly greater with Artificial Tears Ointment® compared with other lubricant formulations from 1 to 20 min post-administration. Median (range) precorneal retention times were significantly different among the 5 lubricants, ranging from 40 minutes (20-90 min) for Artificial Tears Ointment®, 35 min (20-90 min) for Systane® Ultra, 30 min (10-60 min) for I-Drop® Vet Plus, 25 min (10-60 min) for Optixcare® Eye Lube Plus, and 10 min (10-20 min) for Artificial Tears Solution®. Precorneal retention time was significantly lower for Artificial Tears Solution® compared with the other 4 formulations. CONCLUSIONS: This study established normative data for the retention time of common lubricants on the ocular surface of dogs, which may be used to guide clinicians with their choice of lubricant and frequency of administration.

An investigation into the development of qualitative tear film disorders in dogs following cryoepilation for distichiasis.

OBJECTIVE: The aim of this prospective study was to compare tear film quality between dogs who have previously undergone cryoepilation for distichiasis to a reference population. ANIMALS STUDIED: Nine dogs (17 eyes) were recruited after surgery and were compared to a reference population of 21 dogs (42 eyes). PROCEDURES: Canine patients who had previously undergone cryoepilation for distichiasis for a minimum of 1 month prior to examination were recruited. A complete ophthalmic examination was performed by an ABVO resident (BDR), with additional tear tests, including tear film interferometry, infra-red meibography, and a tear film break-up time (TFBUT) performed. The tear test results were compared to a reference population obtained from client-owned dogs with no history of ophthalmic complaints, a normal ophthalmic examination performed by an ABVO resident (BDR) and a Schirmer Tear Test-1 > 15 mm/min. Statistical analysis was performed of the results obtained. RESULTS: The treated group was significantly more affected with meibomian gland dropout (MG-dropout) in 11/17 (64.7%) cases, compared to the reference population of 2/21 (9.5%) (p < .01). The treated group had an odds ratio of 23.8 to develop MG-dropout compared to the reference population (p < .01). Tear film breakup time (TFBUT) was significantly shorter in the treatment group (5.8 ± 2.6 s) compared to the reference population (10.1 ± 1.1 s) (p < .001). In the treatment group, 12/17 (70.5%) of treated eyes had a TFBUT < 5 s compared to 2/21 (9.5%) of the reference population. CONCLUSION: Cryoepilation for distichaiasis appears to be a risk factor for developing MG-dropout and qualitative tear film disorders post-operatively in canines.

A review of diagnostic tests for qualitative and quantitative tear film deficiency in dogs.

Dry eye disease (DED) is a complex multifactorial condition caused by loss of ocular surface homeostasis from quantitative and/or qualitative tear film deficiency. Schirmer tear test (STT) is often the only diagnostic test used to assess for DED in veterinary practice. STT is invaluable in the diagnosis and monitoring of quantitative tear film deficiency (i.e., keratoconjunctivitis sicca); however, it is not sufficient to optimize therapy and fully recognize other contributing factors for the disturbance in ocular surface homeostasis. The present work reviews diagnostic tests for assessing aqueous tear production in veterinary medicine, as well as the quality of tears, corneal epithelial barrier integrity, and the lacrimal functional unit.

A comparative review of evaporative dry eye disease and meibomian gland dysfunction in dogs and humans.

Dry eye disease is a complex ophthalmic disorder that consists of two main subtypes, aqueous deficient dry eye (ADDE) and evaporative dry eye disease (EDED). Due to the complex underlying physiology, human dry eye disease can be difficult to model in laboratory animal species. Thus, the identification and characterization of a spontaneous large animal model of dry eye disease is desirable. Dogs have been described as an ideal spontaneous model of ADDE due to the similar pathophysiology between dogs and humans. Recently, EDED and meibomian gland dysfunction (MGD) have been increasingly recognized and reported in dogs. These reports on EDED and MGD in dogs have identified similarities in pathophysiology, clinical presentations, and diagnostic parameters to humans with the comparable disorders. Additionally, the tests that are used to diagnose EDED and MGD in humans are more easily applicable to dogs than to laboratory species due to the comparable globe sizes between dogs and humans. The reported response of dogs to EDED and MGD therapies are similar to humans, suggesting that they would be a valuable preclinical model for the development of additional therapeutics. Further research and clinical awareness of EDED and MGD in dogs would increase their ability to be utilized as a preclinical model, improving the positive predictive value of therapeutics for EDED and MGD in both humans and dogs.

Effect of 0.15% sodium hyaluronate on tear film breakup time in healthy anesthetized cats.

OBJECTIVES: This study aimed to evaluate the effect of 0.15% sodium hyaluronate (SH) on tear film breakup time (TFBT) in healthy anesthetized cats. PROCEDURES: Forty cats undergoing elective surgery were enrolled. TFBT was assessed before anesthesia to obtain baseline values. As a preanesthetic medication, cats received midazolam, tramadol, and cetamine combined in the same syringe. For anesthetic induction and maintenance, propofol and isoflurane were used. After a 15 min stabilization period to achieve the surgical anesthetic plane, one eye was treated with one drop of SH, while the other eye received saline and served as a control. TFBT was measured at the end of the general anesthesia (T40) and 35 (T75) and 80 min (T120) after the termination of the anesthesia. TFBT values were compared between the control and SH-treated eyes; both values were also compared with the baseline values (p < .05). RESULTS: In the control eyes, TFBT significantly decreased from baseline at all time points (p < .001), while in SH-treated eyes, TFBT significantly increased from baseline only at T40 (p < .0001). In SH-treated eyes, TFBT was significantly higher than that in the control eyes at all time points (p < .001). CONCLUSIONS: In healthy cats, TFBT decreases significantly after 40 min of general anesthesia, and one drop of 0.15% sodium hyaluronate was able to maintain the stability of the tear film for up to 75 min in treated eyes. However, the isolated effect of each drug used in our anesthetic protocol on TFBT should be executed in further studies.

The Effects of Fisetin on Cyclosporine-Treated Dry Eye Disease in Dogs.

Dry eye disease (DED) is a chronic debilitating ophthalmological disease with the current therapeutic options focused on the suppression of the symptoms. Among the possibilities of how to improve DED therapy, polyphenols have shown an enormous capacity to counteract DED functional changes. The study aimed to specifically target pathophysiological mechanisms by the addition of fisetin to the cyclosporine treatment protocol. We examined dog patients with DED on cyclosporine treatment that were administered 0.1% fisetin or fisetin-free eye drops. For the assessment of fisetin effects, tear film production and matrix metalloproteinase 9 (MMP-9) were studied in the tear film. Tear production was not recovered after 7 or 14 days (9.40 mm ± 6.02 mm, p = 0.47; 9.80 mm ± 6.83 mm, p = 0.53, respectively). MMP-9 levels significantly increased after 7 days and then dropped after 14 days (775.44 ng/mL ± 527.52 ng/mL, p = 0.05; 328.49 ng/mL ± 376.29 ng/mL, p = 1.00, respectively). Fisetin addition to cyclosporine DED treatment was not able to restore tear fluid production but influenced molecular pathological events through MMP-9.

Clinical parameters obtained during tear film examination in domestic rabbits.

BACKGROUND: One of the contributing factors to ocular surface health is a stable precorneal tear film. Considering the increasing interest in rabbits as pets and the limited literature available on domestic rabbit tearing, the aim of this study was to establish normative data for examination of the tear film in domestic rabbits. RESULTS: The study included 75 client-owned domestic Holland Lop rabbits (150 eyes). The following examinations were performed in each eye: Schirmer tear test-1, tear osmometry, interferometry, tear meniscus height measurement and meibography (quantifying meibomian gland loss as a percentage). The resulting median (95% central range) values were 10.0 (5.0-17.3) mm/min for the Schirmer tear test-1, 345.0 (280.5-376.1) mOsm/L for tear osmolarity, grade 2 (1-4) of interferometry, 0.28 (0.20-0.47) mm for tear meniscus height and 0.0 (0.0-67.6) % meibomian gland loss. A significant association was found between tear osmolarity and age, with an estimated decrease of - 4.0 mOsm/L with each additional year of age (p < 0.001). The distributions of interferometry grades were significantly different between males and females (p < 0.001), with grade 1 and grade 2 being the most frequent in females and males, respectively. A weak negative correlation was also observed between interferometry grade and the percentage of meibomian gland loss (r = - 0.22, p = 0.006). CONCLUSIONS: This is an original study that documents extensive tear film parameters in healthy Holland Lop rabbits. The results can be used as normative data for the examination of the tear film in this lagomorph breed.

Assessment of tear film osmolarity using the IPen® Vet osmometer in Pug and Shih-Tzu dogs with and without keratoconjunctivitis sicca.

OBJECTIVE: To establish tear film osmolarity (TFO) values in Pugs and Shih-Tzus, with and without keratoconjunctivitis sicca (KCS). ANIMALS STUDIED: A total of 82 adult dogs were evaluated. PROCEDURE: The inclusion criteria for the healthy group was a Schirmer tear test (STT-1) ≥15 mm/min with no clinical signs of KCS, whereas those with KCS had clinical signs and a STT-1 ≤10 mm/min. All animals underwent complete ophthalmological evaluation prior to STT-1 and TFO. Student's t tests were used to compare STT-1 and TFO in KCS and healthy eyes as well as possible differences in TFO between breeds. In addition, a linear regression to model the relationship between the two variables (STT-1 and TFO) was performed. A P-value ≤ 0.05 was considered statistically significant. RESULTS: STT-1 results were significantly lower (p = 0.0001) in the KCS group (4.46 ± 1.74) compared with the control group (18.80 ± 2.02). Mean TFO results were significantly higher in the KCS group (353.02 ± 16.58 mOsm/L) (p < 0.0001) compared with the control group (315.27 ± 6.15 mOsm/L). The formula Y = 365.059-2.625 * X significantly predicts (p < 0.001) the value of the variable Y (TFO mOsm/L) as a function of the variable X (STT-1 mm/min), with a coefficient of determination of 0.71. CONCLUSIONS: The results revealed differences in TFO and STT-1 between KCS and healthy dogs. Additionally, STT-1 and TFO values were correlated with the aim to use STT-1 values to predict TFO values in brachycephalic breeds.

Environmental relative humidity affects Schirmer tear test results in normal dogs.

OBJECTIVE: To investigate the effects of environmental temperature and relative humidity on tear test results in dogs. ANIMALS STUDIED: 22 normal dogs. PROCEDURES: Routine Schirmer tear tests (STT1) and phenol red thread tests (PRTT) were administered to normal dogs in four environmental conditions with different relative humidity (RH) and temperature (T). Environmental conditions (mean ± SD) included the following: normal indoor (RH = 49 ± 4%, T = 72 ± 2°F), outdoor (RH = 62 ± 11%, T = 85 ± 6°F), indoor high humidity (RH = 85 ± 6%, T = 71 ± 1°F), and indoor low humidity (RH = 39 ± 2%, T = 76 ± 1°F). ANCOVA models were used to assess for significant associations between tear test readings and RH/T (P < .05). RESULTS: A significant, direct positive relationship between RH and STT1 results was detected (y = 0.04909*X + 19.11, P = .006) but not between T and STT1. There was no significant relationship between PRTT and RH or T. CONCLUSIONS: These results suggest that STT1 but not PRTT is affected by RH and that T does not influence STT1 or PRTT results in normal dogs. RH is unlikely, however, to cause clinically significant effects on STT1 readings in normal dogs when performed in average indoor conditions. Future studies should investigate the influence of RH on STT1 readings obtained in dogs with keratoconjunctivitis sicca.

Conjunctival staining with lissamine green as a predictor of tear film deficiency in dogs.

OBJECTIVE: To evaluate a grading scheme for conjunctival staining patterns with lissamine green ocular dye in the diagnosis of tear film deficiencies in dogs. PROCEDURES: Client-owned and research colony dogs were enrolled in a prospective study between February and October 2018 in which slit-lamp biomicroscopy, Schirmer tear test (STT), tear film breakup time (TFBUT), conjunctival lissamine green staining (LGS), and intraocular pressure (IOP) measurement were performed in both eyes of all dogs. Lissamine green staining of the temporal bulbar conjunctiva was graded from 0-3, with a higher grade corresponding to an increased stain intensity. RESULTS: Fifty-four dogs (107 eyes), comprising 31 males and 23 females with a mean age of 5.0 ± 3.9 years (range 0.5-14.3), were enrolled in the study. STT was <15 mm/min in 21 eyes and ≥15 mm/min in 86 eyes. Lissamine green staining grade for eyes with a STT of <15 mm/min (2.0 ± 0.9) was significantly higher than for eyes with a STT ≥15 mm/min (0.2 ± 0.7) (P < .001). TFBUT for eyes with a STT <15 mm/min (6.5 ± 4.4 seconds) was significantly shorter than for eyes with a STT ≥ 15 mm/min (16.1 ± 3.6 seconds) (P < .001). As LGS grade increased, both STT (P < .001) and TFBUT (P < .001) significantly decreased. CONCLUSIONS: A higher LGS grade was significantly associated with a lower STT and more rapid TFBUT in dogs. Lissamine green ocular dye can be considered as an adjunctive diagnostic test when evaluating tear film deficiency in dogs.

A retrospective evaluation of systemic and/or topical pilocarpine treatment for canine neurogenic dry eye: 11 cases.

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.

Effects of 5% sodium chloride ophthalmic ointment on thickness and morphology of the normal canine cornea.

OBJECTIVE: To determine the effect of 5% sodium chloride ophthalmic ointment (5% NaCl) on thickness and morphology of the normal canine cornea using ultrasonic pachymetry (USP), in vivo confocal microscopy (IVCM), and Fourier-domain optical coherence tomography (FD-OCT). METHODS: Five healthy laboratory Beagles received ophthalmic examinations including USP, IVCM, and FD-OCT prior to and at fixed intervals following treatment. The right and left eyes were treated with 5% NaCl and artificial tears ophthalmic ointment (AT), respectively, every 2 hours for 4 treatments/d (days 2-9), and then hourly for 7 treatments/d (day 10). Treatment groups were statistically compared using mixed-effects linear regression. RESULTS: Treatment with 5% NaCl resulted in a 12 µm decrease in corneal thickness from baseline (P < .001), while there was no significant difference in corneal thickness between values obtained at baseline and following treatment with AT (P = .82). Epithelial cell density significantly increased from baseline (530 ± 52 cells/mm2 ) to 577 ± 43 and 567 ± 15 cells/mm2 with 5% NaCl and AT, respectively (P = .003 and .005, respectively). However, keratocyte cell density in the anterior and posterior stroma and endothelial cell density did not significantly differ following treatment with 5% NaCl or AT ointment (P > .05). CONCLUSIONS: Short-term topical treatment with 5% NaCl decreased corneal thickness in normal dogs with no observable changes in corneal morphology or signs of ocular toxicity.

Tear clearance rate in dogs: Measurement using anterior segment optical coherence tomography.

OBJECTIVE: The tear clearance rate (TCR), determined using anterior segment optical coherence tomography (AS-OCT) images, and its correlation with ocular surface parameters, including blink rate, Schirmer tear test-1 (STT-1) and tear film breakup time (TFBUT), were evaluated. ANIMALS STUDIED: Left eyes of 20 client-owned dogs with no ocular disease symptoms. PROCEDURES: The tear meniscus height (TMH) was evaluated using AS-OCT images before the instillation of 5 µL saline (TMHbase ), immediately post-instillation (TMH0 ), 30-s post-instillation (TMH0.5 ) and at 1 min intervals for 5 min post-instillation (TMH1 , TMH2 , TMH3 , TMH4 and TMH5 ). The TCR was calculated using the formula [(TMH0  - TMH0.5 )/TMH0 ]×100 (%). The eyes were classified into two groups with the median: 'High TMHbase ' (n = 10) and 'Low TMHbase ' (n = 10). Eyes with STT-1 values ≥15 mm/min and TFBUT ≥ 12 s were assigned to the 'Satisfied' subgroup, whereas eyes not satisfying these criteria were assigned to the 'Not satisfied' subgroup. RESULTS: TMH0 was higher than TMH0.5 (p = 0.02), wherein TMH0.5 to TMH5 did not differ significantly. The TCR and blink rate were negatively correlated (p = 0.02). The 'Not satisfied' subgroup in the low TMHbase group had a lower TCR (p = 0.02) and higher blink rate (p = 0.04) than the 'Satisfied' subgroup. CONCLUSIONS: TCR can be evaluated using AS-OCT in dogs. Eyes with a lower TCR blink more frequently. TMH merits studying to understand ocular surface health.

Developing a diagnosis model for dry eye disease in dogs using object detection.

The purpose of this study was to develop an object detection method for the diagnosis of dry eye disease (DED) in dogs. To this end, a methodology was designed to evaluate ocular surface video images using the YOLOv5 model, which is an object detection algorithm that has been widely used because of its simple network structure and fast detection speed. Because the cornea is a transparent organ, an illuminator plate with grid squares was used to provide grid lines, which were analyzed as the reflected straight lines of the light source representing the precorneal tear film (PTF) stability. The original video consisted of the number of 12 normal images(normal, [Formula: see text] = 17) and the number of 15 abnormal images(abnormal, [Formula: see text] = 17), converted to JPEG images for labeling, learning, and model validation. The labeled image data were divided into a training image data set (normal, [Formula: see text] = 15,276; abnormal, [Formula: see text] = 26,196) to a validation image data set (normal, [Formula: see text] = 6546; abnormal, [Formula: see text] = 11,228). As a result of the experiment, the mean average precision ([Formula: see text]) achieved 0.995. This study proposes a method to effectively determine ocular surface status in dogs by using YOLOv5 and concludes that an object detection model can be used in the veterinary field.

Corneal protective effects of novel tear substitutes containing sodium hyaluronate and dodecahydrosqualene, squalane, in a porcine dry eye model.

To develop a novel tear substitute (TS) containing sodium hyaluronate (SH) and dodecahydrosqualene (DHS, squalane), we improved the prescription of a previously developed TS containing saline, 0.5% SH and 1% castor oil (CO), which had corneal protective effects against 60-min desiccation in a porcine dry eye model and viscosity of 106.8 mPa·S. Fresh porcine eyes were treated with a TS containing saline, 0.1%, 0.25%, 0.3% or 0.5% SH, and 1% CO or 1%, 2.5% or 5% DHS, and TS-treated eyes were desiccated for up to 180 min. The corneal damage was evaluated by the staining score of methylene blue (MB), absorbance of MB extracted from the cornea, the staining density of lissamine green (LG) and histopathology. The viscosities of the examined TS were also measured. A saline/0.5% SH/1% DHS solution had corneal protective effects for 90 min under desiccation and a viscosity of 110.0 mPa·s. A TS with saline, 0.1%, 0.25% or 0.3% SH and 1% or 2.5% DHS did not have better protective effects than a saline/0.5% SH/1% DHS solution, although a saline/0.3% SH/5% DHS solution exhibited greater corneal protection against 180-min desiccation on MB and LG staining and histopathological examination, and its viscosity was 34.5 mPa·s, which was similar to the 29.5 mPa·s of 0.3% SH. The saline/0.3% SH/5% DHS solution is available as a novel 3-hr long-lasting TS containing mucinomimetic and liquid oil components to treat and relieve dry eye symptoms in animals and humans.

Reference values for selected dry eye tests in normal Beagle dogs: a pilot study.

BACKGROUND: Dry eye disease (DED) cannot be diagnosed by a single test because it is a multifactorial disorder of the ocular surface. Although studies on various dry eye tests (DETs) in dogs have been reported, standard criteria have not been established except for the Schirmer tear test 1 (STT-1). OBJECTIVES: To establish reference values for DETs in dogs with normal STT-1 values (≥ 15 mm/min) and to analyze the correlation between DETs. METHODS: The STT-1 was performed in 10 healthy Beagle dogs (20 eyes). After 20 min, interferometry (IF) for estimating the lipid layer thickness (LLT) of the tear film, tear meniscus height (TMH), non-invasive tear breakup time (NIBUT), and meibomian gland loss rate of the upper eyelid (MGLRU) and lower eyelid (MGLRL), were measured using an ocular surface analyzer. RESULTS: Mean values for STT-1, TMH, and NIBUT were as follows: 21.7 ± 3.4 mm/min, 0.41 ± 0.21 mm, and 19.1 ± 9.5 sec, respectively. The most frequent LLT range, measured by IF, was 30-80 nm (11 eyes), followed by 80 nm (5 eyes) and 80-140 nm (4 eyes). MGLRU ≤ 25% was measured in 11 eyes and 26%-50% in 9 eyes; MGLRL ≤ 25% in 8 eyes and 26%-50% in 12 eyes. Besides positive correlation between TMH and NIBUT (P = 0.038), there were no significant associations between DETs. CONCLUSIONS: Data obtained in this study provided normative references that could be useful for diagnosing DED and for further research into correlation between DETs in dogs with DED.

Evaluation of ocular surface parameters in dogs with and without meibomian gland dysfunction.

BACKGROUND: Interest in meibomian gland dysfunction (MGD) is growing in veterinary medicine. However, research on MGD in dogs is lacking. The aims of this study were to compare the interferometry grades, tear meniscus height (TMH) and non-invasive tear break-up time (NIBUT) grades between dogs with and without MGD. METHODS: Routine ophthalmic examination, interferometry, NIBUT assessment, TMH measurement and meibography were performed. Age and Schirmer tear test-1 (STT-1) results were compared between the control and MGD groups using Student's t-test. Interferometry grades, NIBUT grades and TMH were compared between the two groups using Mann-Whitney U-test. RESULTS: There was no significant difference in age between the two groups (p = 0.279). STT-1 (p = 0.024), interferometry (p = 0.004) and NIBUT grades (p = 0.012) were significantly lower in the MGD group than in the control group. No significant difference in TMH values (p = 0.587) was observed between the two groups. While the control group included 18 and seven eyes in meiboscore 0 and 1, in MGD group, 12, eight, five and three eyes were included in meiboscore 0, 1, 2 and 3, respectively. CONCLUSIONS: Low interferometry and NIBUT grades were associated with MGD, suggesting decreased meibum and disrupted tear film quality. TMH did not differ between the two groups. Meibography could aid in the diagnosis of MGD in severe cases, although it could not detect early MGD in the dogs in this study.

Efficacy of topically applied liposome-bound tetracycline in the treatment of dry eye model.

OBJECTIVE: To evaluate the effects of liposome-bound tetracycline eye drops in a rabbit dry eye model evaluating their advantage of being less allergic, preservative free and prolonged action compared with other tear substitutes. PROCEDURES: New Zealand albino rabbits were equally divided into control group and dry eye induced groups. Dryness was induced in 24 eyes of 12 healthy adult male albino rabbits by instilling atropine sulfate eye drops 1% three times daily for 1 week, then animals were subdivided into four groups; group 1 (rabbits with dry eye model), groups 2, 3, and 4: rabbits with dry eye model treated for 7 days starting on 7th day of dryness induction with either tetracycline, empty liposome, or combined tetracycline with liposome as topical eye drops respectively. Schirmer (STT) test and tear break up time (TBUT) were assessed on days 0, 2, 4, 7, 9, 11, and 14. Animals were sacrificed on day 14 and histopathological examination of the cornea and conjunctiva was performed. RESULTS: Tear break up time and STT test values were significantly improved in groups 2, 3, 4 as compared with group 1. The histopathological examination showed normal cytoarchitecture of corneas and conjunctivae in groups 2, 3, 4 against the dryness effect that continued to affect the cornea and conjunctival epithelium in group 1. There was a significant improvement in the group treated with liposome-bound tetracycline eye drops (group 4) as compared with tetracycline alone (group 2) and empty liposome (group 3). CONCLUSION: The use of liposome encapsulated tetracycline significantly improved STT and TBUT values as well as reverse surface ocular pathology.

The Impact of Surgical Excision of the Orbital Lacrimal Gland on the Aqueous Tear Production and Ocular Surface Health in Donkeys (Equus asinus).

The exact contribution of the orbital lacrimal gland (OLG) is unknown and is still a subject of debate and inconsistency in literature. Currently, there are no detailed studies addressing the influence of the OLG removal on tear production in equines. This study aimed to address the influence of surgical excision of the OLG on aqueous tear production and ocular surface health in donkeys. The study was conducted on six clinically healthy donkeys with no ophthalmic abnormalities. In each donkey, the OLG of the left eye was surgically excised, whereas the right eye was served as a control. External ophthalmic examination, Schirmer tear test (STT) I and II, tear pH, fluorescein staining test were conducted on both eyes, preoperatively and at one-week intervals for 60 days, postoperatively. There were significant decreases in STT I and II values (P = .0001 and .0001, respectively), whereas tear pH values showed a significant increase (P = .0001) in the operated eyes compared with the control ones. There were no overt clinical signs characteristics of keratoconjunctivitis sicca (KCS) in the operated eyes. However, there was evidence of microinjury of the keratoconjunctival epithelium evidenced by positive fluorescein uptake, postoperatively. Surgical excision of the OLG significantly diminished the aqueous tear production and threatened the corneal epithelium as a result of corneal dehydration. On the contrary to the recommendations of other studies, eyes subjected to this procedure should receive treatment of dry eye to prevent development of KCS, postoperatively.

Restasis for the treatment of 'dry eye' in Aotus nancymaae.

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.