Prevalence of feline cataract: results of a cross-sectional study of 2000 normal animals, 50 cats with diabetes and one hundred cats following dehydrational crises.

Objective: In this study 2000 normal cats, 50 cats with diabetes and 100 cats with a history of dehydrational crises were examined ophthalmoscopically to determine presence of cataract.
Materials and Methods: The cats examined were predominantly from veterinary hospital populations but also from re-homing facilities and breeding catteries. Prevalence of cataract was determined for different age groups (year cohorts). The age at which prevalence of cataract was 50% (C(50)) was determined indirectly from a fitted prevalence curve as previously described. C(50) was determined for animals of different genders and different breeds as well as for those with diabetes and histories of dehydrational episodes related to chronic renal failure, chronic vomiting or chronic diarrhea.
Results: The mean +/- standard deviation of C(50) for all normal cats in the study was 12.7 +/- 3.4 years. All cats over 17.5 years were affected by some degree of lens opacity. C(50) for cats with diabetes was 5.6 +/- 1.9 years (significantly different from normal cats at P < 0.0001). For cats with a history of dehydrational crises C(50) was 9.9 +/- 2.5 (difference from normal cats nearing statistical significance at P = 0.06).
Conclusions: The study yields novel findings regarding the prevalence of age-related cataract in normal cats together with cats with diabetes and history of previous dehydrational episodes in which prevalence of cataract is increased.