Detection of Glaucoma and Its Association With Diabetic Retinopathy in a Diabetic Retinopathy Screening Program

Purpose: To determine the type of glaucoma in subjects with diabetes mellitus detected during a diabetic retinopathy screening program and to determine any association between diabetic retinopathy (DR) and glaucoma. Materials and Methods: This is a population-based prospective cross-sectional study, in which subjects with diabetes mellitus underwent screening for DR in a primary care outpatient clinic. Digital fundus photographs were taken and graded for presence/absence and severity of DR. During this grading, those fundus photographs showing increased cup-to-disc ratio (CDR) (>= 0.6) were identified and these patients were referred to the specialist ophthalmology clinic for detailed examination. The presence of glaucoma was established based on CDR and abnormal visual field (VF) defects according to Hodapp-Parrish-Anderson's criteria. An elevation of intraocular pressure was not required for the diagnosis of glaucoma. The patients said to have definite glaucoma were those with vertical CDR >/= 0.6, glaucomatous defects on VF examination, or retinal nerve fiber thinning if VF was unreliable. Results: Of the 2182 subjects who underwent screening, 81 subjects (3.7%) had increased CDR and 40 subjects (1.8%) had confirmed glaucoma. Normal-tension variant of primary open-angle glaucoma was the most prevalent type (1.2%) We did not find any evidence that DR is a risk factor for glaucoma [odds ratio for DR vs. no DR = 1.22 (95% confidence interval, 0.59-2.51)]. Conclusion: The overall prevalence of glaucoma in this diabetic population, based on finding increased cupping of optic disc in a teleretinal screening program was 1.8% (95% confidence interval, 1.0-3.0).