BackgroundThe 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.MethodsThree 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.ResultsA 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 (P<0.001). 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).ConclusionsThis 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 The present study aimed to determine the effects of age, sex, reproductive status, skull type, and nasolacrimal duct (NLD) patency on tear production and tear film breakup time (TBUT) in normal dogs. Animals studied The ophthalmic data of 82 healthy adult dogs were evaluated in this study. Procedures Age, sex, breed, and reproductive status were recorded. Schirmer tear test (STT) and TBUT were assessed in all dogs, and interferometry was available for the selected dogs. The Jones test was used to evaluate NLD patency. The cephalic index (CI) was calculated for each dog (skull width/skull length ×100). Results Mean (SD) values for the STT results for the right (OD) and left (OS) eyes were 20.6 (2.7) and 20.2 (2.7) mm/min, respectively. Mean (SD) TBUT values for OD and OS were 6.5 (2.5) and 6.1 (2.3) mm/min in all dogs, respectively. Sex and reproductive status had no significant effect on STT and TBUT (P[OU] > 0.05). Skull type significantly affected TBUT in both eyes (P(OD) = 0.01, P(OS) = 0.003), but had no effect on STT (P[OU] > 0.3). Age had no correlation with STT and TBUT in either eye (P[OU] > 0.05). STT and TBUT had no correlation in either eye (P[OU] > 0.2). NLD patency had no significant effect on STT or TBUT (P[OU] > 0.1). Conclusions The results of this study showed lower TBUT values in brachycephalic breeds than in non‐brachycephalic breeds. A compensatory increase in STT values was observed in dogs with low TBUT values.

This study compared the STT I values of the dorsal and ventral conjunctival fornices in cats. The difference was significant between the L-STT I and U-STT I values; however, the L-STT I and U-STT I values were within normal reference intervals. The U-STT I data have diagnostic value that might be of benefit in cases where there is a problem in the ventral conjunctival fornix.

This study was performed to determine the normal seasonal aerobic and an-aerobic corneoconjunctival bacterial flora in cats. Thirty eyes of 15 clinically normal client-owned Persian cats were evaluated. All cats lived in a similar indoor/outdoor home environment being fed the same diet for the entire year. The cats did not receive any medications and were found to be clinically healthy 1 week prior to each microbial sampling. The cats were not exposed to other cats during the study period. Microbial samples were collected at the same time of day on the first day of the second month of each of the four seasons. During sample collection, a sterile swab was rolled over the corneoconjunctival surface avoiding contact with surrounding skin or hair. Immediately after sample collection, microbiologic aerobic and anaerobic cultures were initiated. Gram-positive bacteria were the most prevalent isolates. The most commonly isolated bacterial organisms across all seasons were Staphylococcus epidermidis (41/95; 43.2%),-hemolytic streptococcus (18/95; 18.9%), Staphylococcus aureus (17/95; 17.9%), and Escherichia coli (11/95; 11.5%). Twenty-five cultures of a total of 120 (20.8%) were negative. One negative culture was collected in the summer, while 21 cultures were negative in fall and winter. Gram-positive bacteria were the predominant microorganisms of the normal ocular surface of healthy cats in all seasons in this study. This result is in agreement with previous publications.