Schirmer Tear Test Values Research Articles

Tear‐film osmolarity in normal cats and cats with conjunctivitis

To compare the tear-film osmolarity of normal cats and cats with conjunctivitis. The population consisted of shelter, research, and privately owned cats. Cats were classified as normal or having conjunctivitis. An ophthalmic examination including Schirmer tear test (STT), fluorescein staining, tear-film break-up time (TFBUT), intraocular pressure (IOP), and slit-lamp biomicroscopy of the anterior segment was performed. The severity of conjunctivitis was graded and assigned a numerical score. The Tear Lab(TM) Osmolarity System was utilized to determine the tear-film osmolarity. Unpaired t-tests were used to compare tear-film osmolarity, TFBUT, IOP, and STT of the two groups. A total of 93 cats (186 eyes) were examined. There were 37 normal cats (74 eyes) and 39 conjunctivitis cats (78 eyes). The mean age was 2.34 years. There was no statistical difference (P = 0.2065) between the median tear-film osmolarity of normal cats (328.5 ± 17.94 mOsms/L) and conjunctivitis cats (325.0 ± 24.84 mOsms/L). Cats with conjunctivitis had an accelerated TFBUT (P < 0.0001) and lower IOPs (P < 0.0001) as compared to normal cats. No statistical difference was found between STT values (P = 0.1304). The median tear-film osmolarity of normal cats was 328.5 mOsms/L. Despite the accelerated TFBUT, conjunctivitis did not cause a statistically significant change in tear-film osmolarity. The Tear Lab(TM) Osmolarity System was easily used and well tolerated by the cats in the study.

Superficial keratectomy and 360º conjunctival flap for bullous keratopathy in a dog: a case report

A case of a two-year-old male Pinscher with a history of discomfort in the right eye was reported. The left eye had been enucleated by the referring veterinarian due to the same symptom with unsuccessful clinical treatment. The Schirmer tear test value was elevated and a decreased intraocular pressure was observed by applanation tonometry. Biomicroscopy revealed profuse corneal edema and keratoconus and fluorescein staining was negative. Gonioscopy and ophthalmoscopy did not provide any relevant data due to the corneal alterations. Bullous keratopathy was diagnosed. Surgery was performed in two steps: 1) superficial keratectomy and 360º conjunctival flap, and 2) superficial keratectomy to restore corneal transparency. Thirty days after the second superficial keratectomy, the third eyelid flap was removed. Conjunctivalization of the upper nasal quadrant of the cornea was observed. The axial portion of the cornea was transparent and vision was restored.

The Pharmacologic Assessment of A Novel Lymphocyte Function-Associated Antigen-1 Antagonist (SAR 1118) for the Treatment of Keratoconjunctivitis Sicca in Dogs

Keratoconjunctivitis sicca (KCS) is characterized by inflammation and decreased production of tears containing increased levels of cytokines. The release occurs in the setting of conjunctival and lacrimal gland inflammation, potentially mediated by the interaction between lymphocyte function-associated antigen (LFA)-1, a cell surface protein found on lymphocytes, and its cognate ligand intercellular adhesion molecule (ICAM)-1. SAR 1118 is a novel LFA-1 antagonist and may be an effective therapeutic agent for the treatment of KCS. The following studies were performed to assess the in vitro activity of SAR 1118 and to evaluate the clinical efficacy of topical SAR 1118 for the treatment of idiopathic canine KCS. Pharmacodynamics were assessed by measuring the ability of SAR 1118 to inhibit Jurkat T-cell binding with recombinant human ICAM-1 and to inhibit cytokine release from human peripheral blood mononuclear cells (PBMCs) stimulated by staphylococcal enterotoxin B. For the assessment of clinical efficacy, 10 dogs diagnosed with idiopathic KCS were treated with SAR 1118 1% topical ophthalmic solution three times daily for 12 weeks. Schirmer's tear test (STT) was used to measure tear production. SAR 1118 demonstrated concentration-dependent inhibition of Jurkat T-cell attachment, inhibition of lymphocyte activation, and release of inflammatory cytokines, particularly the Th1, Th2, and Th17 T-cell cytokines IFN-γ, IL-2, and IL-17F, respectively. Mean STT values increased from 3.4 mm during week 1 to 5.8 mm at week 12 (P < 0.025). No SAR 1118-related adverse events were observed. SAR 1118 appears to be an effective anti-inflammatory treatment for KCS. Additional studies are warranted to establish the efficacy of SAR 1118 for the treatment of KCS in humans.

Schirmer tear tests and intraocular pressures in conscious and anesthetized koalas (Phascolarctus cinereus)

To estimate mean Schirmer tear test (STT) and intraocular pressure (IOP) values in healthy koalas both conscious and anesthetized. Data were gathered from koalas in Victoria, Australia. Conscious examinations were performed on captive koalas. Free-ranging (wild) koalas were examined under anesthesia. Anesthesia was induced using alfaxalone, and animals were maintained on oxygen and isoflurane if required. All animals were healthy and had no surface ocular pathology detectable during slit lamp biomicroscopy. STT I tests were performed using commercial STT test strips placed in the lower fornix for 1 min. IOP was measured using an applanation tonometer after topical anesthesia. The higher value of the two eyes for both STT and IOP was analyzed. STT was measured in 53 koalas (34 conscious, 19 anesthetized) and IOP was measured in 43 koalas (30 conscious, 13 anesthetized). A two-sample t-test was used to compare means. A P-value <0.05 was regarded as significant. Mean ± SD is presented. The mean higher STT in conscious koalas was 10.3 ± 3.6 mm wetting/min and in anesthetized koalas it decreased to 3.8 ± 4.0 mm wetting/min (P < 0.0001). The mean higher IOP in conscious koalas was 15.3 ± 5.1 mmHg, and in anesthetized koalas it was 13.8 ± 3.4 mmHg (P = 0.32). There was no effect of sex on either STT or IOP. The mean and SD of STT and IOP values for koalas both conscious and anesthetized were reported. The mean STT was significantly reduced by alfaxalone anesthesia.

Effect of topical 0.5% timolol maleate on tear production as measured by Schirmer tear test in clinically normal horses

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.

Reference values for intraocular pressure and Schirmer tear test in clinically normal Sanjabi sheep

The current study was undertaken to establish reference values for Schirmer tear test (STT) and intraocular pressure (IOP) in the Sanjabi sheep. Twenty apparently healthy Sanjabi sheep with no evidence of ocular disease were used in this study. Tear production was measured by STT by inserting standard sterile Schirmer tear test strip (Ophtechnics Inc., Carson City, NV, USA, Lot number: STR061203) in the ventral conjunctival fornix for 1 min. IOP was measured in both eyes with a Tono-Pen Vet™ (Reichert, Inc. USA). Mean (SD) STT values for all eyes ( n = 40) were 18.52 ± 2.55 mm/min with a range of 13.5–22 mm/min. Comparison of mean STT values between right ( n = 20) and left eyes ( n = 20) showed no differences ( P = 0.88). Mean (SD) IOP values by applanation tonometry were 9.37 ± 2.45 mmHg (range 6–14.5 mmHg). Comparison of mean IOP values between right ( n = 20) and left eyes ( n = 20) showed no differences ( P = 0.59). In conclusion, this study reports STT and IOP findings in Sanjabi sheep, and provide means and ranges for IOP and STT.

Intraocular pressure and tear secretion in Saanen goats with different ages

This study aimed to compare the normal intraocular pressure (IOP) and tear secretion, by means of applanation tonometry and the Schirmer tear test-1 (STT-1), in goats of the Saanen breed with different ages, and at different time points. Thirty six goats, free of ocular abnormalities, were grouped into three different age categories (n=12), animals with 45, 180 and 549 days of age. STT-1 and IOP measurements were carried out always at 9:00am and 7:00pm, during three consecutive days. Results were evaluated statistically (P&lt;0.05). Regarding the time of the day, overall IOP values were significantly lower at 7:00 pm (P&lt;0.001) in individuals with 45 days of age; whereas STT-1 values were significantly higher at 7:00pm (P=0.004) in goats with 549 days of age. Considering the sum of three days, both parameters were significantly lower in individuals with 45 days of age (P&lt;0.001). Intraocular pressure and tear secretion values increase until 180 days of age in the Saanen breed of goats.

Selected Diagnostic Ophthalmic Tests in the Red Kangaroo (Macropus rufus)

The following tests were performed on a total of 20 eyes: Schirmer tear test, intraocular pressure (IOP), assessment of conjunctival flora, and pupillary diameter with application of topical tropicamide in 10 healthy captive red kangaroos (Macropus rufus) under manual restraint. The mean Schirmer tear test value was 22.6 +/- 6.07 mm/min. The mean intraocular pressure was 17.45 +/- 7.23 mm Hg. Values did not differ between eyes or gender for either test, but significant differences were identified for IOP values according to age. The most common bacteria isolated from the conjunctival fornix were Staphylococcus epidermidis (54.5%) and Corynebacterium sp. (18.2%). The mean onset of mydriasis after instillation of 1% tropicamide ophthalmic solution was 16.7 +/- 3.34 min and the mean duration of effect was 17.6 +/- 8.26 hr. The data obtained in this investigation will aid veterinary ophthalmologists and zoo veterinarians to diagnose ocular diseases in the red kangaroo accurately.

Evaluation of nasolacrimal fluorescein transit time in ophthalmically normal dogs and nonbrachycephalic cats

To evaluate fluorescein nasolacrimal transit (NLT) times in ophthalmically normal dogs and nonbrachycephalic cats by use of 2 methods of the Jones test. 73 dogs and 36 cats. Fluorescein dye was applied to the ocular surface of both eyes by means of a wetted fluorescein strip and, in a subsequent test, by administration of a drop of 0.2% fluorescein solution. During each test, the nares were monitored for the appearance of fluorescein for up to 30 minutes after application. Time of fluorescein appearance at the nares was recorded as NLT time. Recorded variables for all study animals included age, reproductive status, body weight, and Schirmer tear test values. For dogs, skull index, snout length, and cephalic conformation were also recorded. Data were grouped for statistical comparisons according to test results. In both dogs and cats, NLT was faster when the fluorescein solution versus fluorescein strip was used. In cats, none of the recorded variables had a significant effect on NLT, irrespective of the testing method used. In dogs, several variables had a significant effect on NLT, including cephalic conformation, snout length, age, and reproductive status, but these findings varied with testing method and testing group. NLT was highly variable in dogs and cats, regardless of testing method used. Assessment of nasolacrimal patency in brachycephalic dogs by use of either method evaluated here is not likely to be clinically useful. In cats, assessment of nasolacrimal patency with the fluorescein drop method was faster and more conclusive than with the fluorescein strip method.

Salivary Gland Involvement in Chronic Graft-Versus-Host Disease: Prevalence, Clinical Significance, and Recommendations for Evaluation

Although xerostomia is a commonly reported complaint in patients with chronic graft-versus-host disease (cGVHD), criteria for evaluating the prevalence and characteristics of salivary gland involvement have not been well defined in this patient population. Previous studies also have made no distinction between salivary and mucosal oral cGVHD. We systematically evaluated signs and symptoms of sicca in a large cohort of patients with cGVHD (n = 101) using instruments widely used to study Sjogren's syndrome. Xerostomia was reported in 60 (77%) patients reporting ocular and 52 (67%) patients reporting oral complaints [corrected]. The salivary flow rate was < or =0.2 mL/min in 27%, and < or =0.1 mL/min in 16%. Histopathological changes, consisting of mononuclear infiltration and/or fibrosis/atrophy, were present in all patients with salivary dysfunction. Importantly, there was no correlation of salivary and oral mucosal involvement in cGVHD. Patients with cGVHD-associated salivary gland involvement had diminished oral cavity-specific quality of life and lower body mass index. Salivary gland involvement is a common and clinically distinct manifestation of cGVHD. Formal evaluation of salivary function using standardized criteria is needed, and this could be incorporated as an outcome measure in clinical trials of cGVHD.

Effect of acepromazine or xylazine on tear production as measured by Schirmer tear test in normal cats

To evaluate the effect of acepromazine or xylazine on Schirmer tear test 1 results in clinically normal cats. Sixteen healthy cross-breed cats. 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. 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 T(15) and T(25) were 4.31 +/- 0.98 (P < 0.001) and 5.18 +/- 1.07 (P = 0.002). The post-treatment mean +/- SEM values in xylazine group were 2.18 +/- 0.97 (P < 0.001) and 2.62 +/- 1.17 (P = 0.001) at 15 and 25 min respectively. Comparison between T(15) and T(25) in acepromazine group (P = 0.49) and xylazine group (P = 0.56) revealed no significant differences. These observations indicate that both acepromazine or xylazine significantly reduced tear production in clinically normal cats. In cats, clinicians should measure STT values prior to utilizing acepromazine or xylazine as sedatives in order to accurately assess the results. Moreover, sterile ocular lubricant or tear replacement should be used as a corneal protectant during sedation with these drugs.

Use of phenol red thread tests to evaluate tear production in clinically normal Amazon parrots and comparison with Schirmer tear test findings

To determine phenol red thread test (PRTT) values in eyes of clinically normal Hispaniolan Amazon parrots before and after topical application of an ophthalmic anesthetic agent and compare findings with Schirmer tear test (STT) values. Evaluation study. 24 Amazona ventralis parrots from a research colony. On 4 occasions (1-week intervals), all birds underwent a thorough ophthalmic examination of both eyes, which included (in sequence) performance of a PRTT and an STT; topical ocular application of proparacaine hydrochloride; and performance of another PRTT and another STT. Correlations between PRTT and STT values recorded with and without topical anesthesia were assessed. Without topical anesthesia, mean +/- SD PRTT value was 12.5 +/- 5.0 mm/15 s (range, 1 to 25 mm/15 s). With topical anesthesia, the PRTT value was 12.6 +/- 5.4 mm/15 s (range, 2 to 24 mm/15 s). Without topical anesthesia, mean STT value was 7.9 +/- 2.6 mm/min (range, 0 to 13 mm/min). With topical anesthesia, the STT value was 5.1 +/- 3.3 mm/min (range, 0 to 18 mm/min). The correlation of PRTT and STT values recorded with or without topical anesthesia was weak (r = 0.51 and r = 0.32, respectively). Results indicated that the PRTT and STT were both viable methods for measurement of tear production in Hispaniolan Amazon parrots. Topical application of an ophthalmic anesthetic agent did not have a significant effect on the PRTT values but significantly decreased the STT values.

Effect of topical 1% tropicamide on Schirmer tear test results in clinically normal horses

To observe the effect of topical 1% tropicamide on equine tear production as measured by Schirmer I tear test. 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. 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. Single dose of topical 1% tropicamide resulted in statistically significant reduction in Schirmer tear test values in clinically normal horses.

Effects of feline herpesvirus type 1 on tear film break-up time, Schirmer tear test results, and conjunctival goblet cell density in experimentally infected cats

To determine the effect of feline herpesvirus type 1 (FHV-1) on tear film breakup time (TFBUT) and Schirmer tear test (STT) values in cats with primary experimental infection and to determine the relationship between TFBUT and STT values and conjunctival goblet cell density (GCD). 9 specific-pathogen-free cats of approximately 6 months of age. 6 cats were inoculated with FHV-1; 3 control cats were sham inoculated. Clinical and histologic evidence of conjunctivitis and TFBUT, GCD, and STT values were assessed at multiple times until postinoculation day (PID) 29. In infected cats, mean clinical and histologic conjunctivitis scores peaked at PID 7 and remained above baseline at PID 29. In control cats, these 2 variables did not change from baseline throughout the study. Mean TFBUT declined rapidly in infected cats up to PID 15 and at PID 29 remained less than baseline, less than for control cats, and below reference range values. Mean STT value for infected cats at PID 29 was increased from baseline but was within the reference range and not different from the value for control cats. Mean GCD in infected cats declined precipitously by PID 7 and remained below reference range values at PID 29. Mean GCD in control cats remained unchanged for the duration of the study period. FHV-1 induced qualitative tear film abnormalities in experimentally infected cats, as measured by TFBUT and GCD. Assessment of TFBUT provided a reasonable clinical estimate of GCD.

Neurologic Evaluation of Acute Lacrimomimetic Effect of Cyclosporine in an Experimental Rabbit Dry Eye Model

To evaluate neurologically acute lacrimation caused by cyclosporine (CsA) eyedrops in rabbit. Normal adult male New Zealand White rabbits and those that underwent parasympathectomy each received a single instillation of 0.1% CsA or vehicle eyedrops. Schirmer tear test (STT) results, flow rate of lacrimal gland (LG) fluid from the excretory lacrimal duct of the main LG, and blink rate (over a 3-minute period) were measured before and after instillation of CsA or vehicle. Light microscopy was performed to examine the main LG in vitro. Protein release from LG fragments was assessed after incubation with CsA for 30 minutes. In normal rabbits, the STT value and the flow rate of LG fluid were significantly increased after treatment with CsA compared with vehicle (P < 0.05). In contrast, no changes were found in denervated eyes. The blink rate of CsA-treated eyes was significantly higher than that of vehicle-treated eyes in normal rabbits (P < 0.005), whereas that of denervated eyes decreased significantly after CsA instillation compared with before administration (P < 0.005). Light microscopy showed that the cytoplasm of acinar cells was packed with secretory granules in denervated LG tissue 7 days after parasympathectomy. The same finding was observed 3 hours after CsA instillation. CsA had no stimulatory effect on protein release by acinar cells in LG fragments at all concentrations tested. These results suggest that CsA has no direct effect on tear fluid secretion from the LG in an acute model. Instead, CsA increases reflex tear flow.

Keratoconjunctivitis sicca attributable to parasympathetic facial nerve dysfunction associated with hypothyroidism in a horse

A 6-year-old 680-kg (1,496-lb) German Warmblood gelding was evaluated because of bilateral blepharospasm and head shaking. Moderate blepharospasm was evident bilaterally, and both eyes had hyperemic and edematous conjunctivas and lusterless corneas. For each eye, the Schirmer tear test value was only 7 mm/min. The horse's nasal mucosa was dry. Abnormal behaviors included mild repetitive vertical movement of the head, snorting, and flehmen response (classic signs of head shaking). Touching the horse's nostrils and face revealed paresthesia and dysesthesia with slight nasolabial muscle hypertrophy bilaterally. Cranial nerve examination revealed no other abnormalities. Serum thyroxine concentration was low, and results of thyrotropin-releasing hormone and thyroid-stimulating hormone stimulation tests were negative, indicating that the horse had hypothyroidism. The diagnoses included keratoconjunctivitis sicca and dry nares attributable to parasympathetic facial nerve dysfunction, head-shaking syndrome with paresthesia and dysesthesia of the face attributable to sensory trigeminal nerve disorder, and hypothyroidism. The 2 nerve dysfunctions were considered peripheral neuropathies that were most likely caused by hypothyroidism. Treatment of both eyes was initiated with topical applications of cyclosporine, 0.5% sodium hyaluronate, and vitamin A ointment. Levothyroxine (20 microg/kg [9.1 microg/lb], PO, q 24 h) was administered. Within 3 weeks to 4 months, serum thyroxine concentration was within reference range, and clinical signs and Schirmer tear test values improved. Hypothyroidism should be considered as a differential diagnosis in horses with peripheral neuropathy or keratoconjunctivitis sicca. In affected horses, administration of levothyroxine may lead to resolution of neurologic signs.

Results of diagnostic ophthalmic testing in healthy guinea pigs

OBJECTIVE-To report values for tear production, central corneal touch threshold (CTT), and intraocular pressure (IOP) in healthy guinea pigs and determine results of aerobic bacterial culture and cytologic examination of conjunctival swab specimens. DESIGN-Cross-sectional study. ANIMALS-31 Healthy guinea pigs (62 eyes) of various ages and breeds. PROCEDURES-Tear production was measured by the phenol red thread tear test (PRT) and Schirmer tear test (STT) before and after topical anesthetic application, CTT was measured with an esthesiometer, and IOP was measured by applanation tonometry. RESULTS-Combining data from all eyes, mean +/- SD PRT values before and after topical anesthetic administration were 21.26 +/- 4.19 mm/15 s and 22.47 +/- 3.31 mm/15 s, respectively, and mean IOP was 18.27 +/- 4.55 mm Hg. Median STT values before and after topical anesthetic administration were 3 mm/min (range, 0 to 12 mm/min) and 4 mm/min (range, 0 to 11 mm/min), respectively, and median CTT was 2.0 cm (range, 0.5 to 3.0 cm). Values did not differ between eyes for any test, but significant differences were identified for PRT values between males and females and between values obtained before and after topical anesthetic administration. Common bacterial isolates included Corynebacterium spp, Streptococcus spp, and Staphylococcus spp. Cytologic examination of conjunctival swab specimens revealed mainly basal epithelial cells; lymphocytes were common. CONCLUSIONS AND CLINICAL RELEVANCE-Results provided information on values for PRT, STT, CTT, and IOP in healthy guinea pigs and on expected findings for aerobic bacterial culture and cytologic examination of conjunctival swab specimens.

Effect of iohexol on tear production and the fluctuations of Schirmer tear test values in clinically normal donkeys

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.

Severe, unilateral, unresponsive keratoconjunctivitis sicca in 16 juvenile Yorkshire Terriers

To present ophthalmic findings, clinical data, and treatment outcomes of 16 juvenile Yorkshire Terriers with severe unilateral keratoconjunctivitis sicca. Each of the 16 dogs exhibited extreme unilateral dryness associated with blepharospasm, mucoid discharge, and corneal vascularization. Ages of affected dogs at presentation ranged from 5 months to 4 years. Mean Schirmer tear test (STT) result for affected eyes was 1 mm/min. Topical application of 0.2% cyclosporine to the affected eye was not associated with improvement in STT values in any dog. Clinical signs subjectively improved with topical application of 20% chondroitin sulfate ophthalmic solution in some dogs, and transposition of the parotid duct was performed in three dogs. Histopathologic examination in one dog failed to show evidence of orbital lacrimal gland tissue. Clinical signs, age of presentation, disease severity, and lack of response to treatment are consistent with breed-related unilateral aplasia or hypoplasia of the lacrimal gland. Lacrimal gland aplasia or hypoplasia should be considered in young dogs with severe unilateral ocular dryness, especially female Yorkshire Terriers.

Reduced tear production in three canine endocrinopathies*

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. 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. 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. 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.