Association between glycaemia, tear production and conjunctival bacterial flora in diabetic dogs with cataracts: A preliminary investigation

Background: Ocular complications of diabetes mellitus, such as dry eye and bacterial infection, are thought to be common in dogs, but their actual incidence is unknown. Therefore, we investigated the associations between glycaemia, tear production and conjunctival bacterial flora in diabetic dogs with cataracts. Methods: The medical records of 30 diabetic dogs with cataracts were retrospectively examined to determine if there was an associations between blood glucose concentration at examination, Schirmer tear test (STT) results and positive bacterial cultures from conjunctival swabs. Results: Eighteen dogs (60%) had low STT results, and 11 dogs (36.6%) with an STT result of 15 mm/min or less were also dysglycaemic. Positive cultures were obtained in 13 dogs (43%), 69% of which had an STT result of 15 mm/min or less and/or an inadequate control of the glycaemia; both conditions were present in 46% of these dogs. No significant association between dysglycaemia and low STT results or positive bacterial culture was detected. An increased risk of a positive bacterial culture, with a statistically significant association with the right eye, was observed in dogs with low STT results. No difference was detected in the bacterial species isolated from dogs with low or normal STT results. Limitations: The small number of cases means that the study may have been insufficiently powered to detect significant correlations. Conclusion: No significant association was found between glycaemia, tear production and conjunctival bacterial flora in diabetic dogs with cataracts.