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Abstract

Background: Diabetes mellitus is a chronic metabolic disorder that predisposes individuals to a range of systemic and ocular complications. Among these, diabetic eye diseases such as cataracts, retinopathy, diabetic macular edema, and corneal changes are significant causes of visual impairment. With the global prevalence of type 1 and type 2 diabetes continuing to rise, the incidence of diabetic cataracts is also expected to increase. Early identification of the most prevalent cataract types in diabetics is crucial for timely intervention and prevention of vision loss.
Objective: To evaluate the common forms of cataract among patients with diabetes mellitus and assess their association with lifestyle and systemic risk factors.
Methods: A descriptive cross-sectional study was conducted on 380 diabetic patients recruited through convenience sampling. Participants were examined at the Ophthalmology and Visual Sciences Department of Dow University of Health Sciences, Ojha Campus, and Dr. Ruth Pfau Civil Hospital, Karachi, between January and April 2025. Inclusion criteria comprised patients with type 1 or type 2 diabetes, while exclusions included neurological disorders, congenital or traumatic cataracts, prior intraocular surgery, gestational diabetes, and secondary causes of diabetes. Visual acuity was tested with a Snellen chart, cataracts were classified via slit-lamp examination (TopCon SL-3C, VOLK 90D lens), blood glucose was measured with a glucometer, and anterior chamber and fundus were evaluated using an ophthalmoscope. Data entry and analysis were performed with Microsoft Excel and SPSS version 26.
Results: The median age was 59 years (range: 52–65), with 207 males (54.5%) and 173 females (45.5%). Type 2 diabetes was predominant (91.1%), while 8.9% had type 1 diabetes. Controlled diabetes was present in 78.2%, and uncontrolled in 21.8%. Nuclear sclerotic cataract was most frequent (55%), followed by posterior subcapsular (23.7%) and cortical cataract (15.8%). Combination forms were less common, including PSCC with nuclear (2.6%), PSCC with cortical (2.4%), and cortical with nuclear (0.5%). Significant associations were observed between cataract type and uncontrolled diabetes (p=0.006), unregulated diet (p<0.001), lack of physical activity (p<0.001), stress (p<0.001), and uncontrolled hypertension (p=0.02). Non-proliferative diabetic retinopathy was observed in 1.6% of cases and showed a significant association with cataract type (p<0.001).
Conclusion: Nuclear sclerotic cataract was the most common form in diabetic patients, particularly in those with uncontrolled diabetes and hypertension. Lifestyle factors such as poor dietary regulation, lack of exercise, and stress further amplified cataract risk. Effective management of glycemic status and hypertension, combined with lifestyle modification, is vital to reducing the burden of cataracts in diabetic populations.