Objective: To determine the frequency and types of age-related cataract in type 2 diabetic patients compared to non-diabetics.

Methods: This comparative, cross-sectional study was carried out at Al-Ibrahim Eye Hospital, Karachi, from July 2014 to June 2015, and comprised both diabetics and non-diabetics. All patients were selected from the out-patient department and had their full ocular examination done, including retinal screening of diabetic patients with nonmydriatic fundus camera. The criterion for diagnosis of cataract was sufficiently advanced lens opacity that caused impaired vision/un-gradable images. Cataract was classified on a morphological basis into cortical, nuclear, posterior sub-capsular and mixed types.

Results: Of the 49,384 patients, 4,556 (9.2%) were diabetics and 44,828 (90.8%) were non-diabetics. Among the diabetics, cataract was found in 1,956 (42.9%) compared to 7,050 (15.7%) in non-diabetics. Adjusted odds ratio (95% confidence interval) between the two groups was 4.40 (range: 4.11-4.71)(p< 0.001). Male-to-female adjusted odds ratio (95% confidence interval) was 2.05 (range: 1.95-2.15)(p< 0.001). Nuclear sclerosis was the commonest type in 2,123 (46.6%) cataract cases in diabetics whereas posterior sub-capsular cataract was the commonest type in 14,480 (32.3%) cases among the non-diabetics.

Conclusion: Cataract was four times more common in diabetics and twice more frequent in men. Nuclear sclerosis was the commonest type of cataract in diabetic patients.