The effect of glycemic control on diabetic cataract progression rate in dogs: A preliminary study

Diabetes mellitus (DM) is a leading cause of canine cataracts. This study aimed to determine the association between diabetic cataracts progression rate and long-term glycemic control in dogs. Nine dogs recently diagnosed with DM and early incipient cataracts were enrolled. Dogs were fitted with sensors for continuous glucose monitoring and underwent biweekly medical and ophthalmic examinations for 6 months or until phacoemulsification surgery was indicated. Measures of glycemic control were compared between dogs that required phacoemulsification surgery (PS) and those that did not (N), and between visits in which surgery was recommended (VS) and all other visits (O). Overall, 4/9 dogs required surgery within 12-24 weeks of recruitment. Coefficient of variation of glucose concentrations was higher in PS than N (P < .001), and was positively associated with cataract progression (P = .023). Average glucose and fructosamine concentrations were higher in VS than O (P ≤ .03). Fructosamine concentrations decreased with time in N (P = .001), but not in PS. Glycemic variability percentage increased with time in PS (P < .001), but not in N. This study shows that cataract progression in diabetic dogs is associated with increased glucose concentrations and glycemic variability. These preliminary findings suggest both measures of glycemic control should be improved in order to slow down cataract progression in dogs.