Prevalence and Associated Risk Factors of Primary Open Angle Glaucoma Among Patients With Type 2 Diabetes Mellitus: A Cross-Sectional Study From North India

Background Glaucoma is a category of disorders that cause visual loss due to damage to the optic nerve. It is the primary cause of irreversible blindness around the globe. In diabetic individuals, intraocular pressure (IOP) was found to be higher than in non-diabetics, and this impact was linked to a rise in fasting blood glucose levels. In light of the foregoing findings, the current investigation was carried out with the goal of determining the prevalence and associated factors for primary open-angle glaucoma in people with diabetes in a tertiary care teaching hospital. Methods This cross-sectional study was carried out in a tertiary care teaching hospital. For a twelve-month period (2021-2022), adult patients (with type 2 diabetes and an age of 18 years or more) attending the ophthalmology out patient department (OPD) were included. Demographic information, socioeconomic data, and medical, familial, and ocular history were all gathered. All individuals with diabetes had an initial ophthalmological evaluation [including best corrected visual acuity (BCVA), slit-lamp biomicroscopy, assessment of peripheral anterior chamber depth (ACD), fundus examination, stereoscopic optic disc evaluation, and IOP measurement] by a senior ophthalmologist. Pearson's Chi-square test was used to compare variables on a nominal scale, whereas the t-test for independent samples was used to examine variables on a continuous scale. Results Our study enrolled a total of 1262 diabetic patients out of which 62.0% of subjects were male. Most of the enrolled subjects belonged to the 61-70 years of age group (35.8%). The eye examination of enrolled subjects showed that out of 1262 diabetic patients, 197 subjects (15.6%) were having primary open-angle glaucoma (POAG). The vision (in the better eye) was analyzed among three groups [no glaucoma or sight-threatening diabetic retinopathy (STDR); only glaucoma; and glaucoma plus STDR] and it was observed that no perception of light (PL) was noticed in 0.2% and 1.2% of subjects in the “no glaucoma or STDR” and “only glaucoma” groups respectively. In our study, the variables significantly associated with the increased prevalence of glaucoma among diabetic subjects included illiteracy, family history of type 2 diabetes mellitus (DM), being hypertensive, non-intake of anti-hypertensive medication, and >10 years duration of DM (p<0.05). Conclusion From our study, we came to the conclusion that there is clear-cut evidence of an increased incidence of POAG in diabetic patients, which was 15.6%. The study also showed a significant association between age, education, diet, hypertension, family history of diabetes and duration of diabetes, and; POAG. However, no significant association was found between gender and POAG.