Purpose: To evaluate and compare the impact of unilateral better-eye and bilateral categorizations of diabetic retinopathy (DR) and diabetic macular edema (DME) on vision-related quality of life (VRQoL) in individuals with type 2 diabetes (T2DM).
Methods: We recruited 390 subjects (116 females; age range, 22-78 years) of Malay, Indian, and Chinese ethnicities from the Singapore Diabetes Management Project (S-DMP), a cross-sectional clinic-based study conducted from 2010 to 2013. Diabetic retinopathy and DME were graded using the Modified Airlie House and American Academy of Ophthalmology classification systems, respectively. Subjects were categorized, using unilateral better-eye classifications, into no DR (n = 189), any DR only (n = 164), and any DME (n = 37); and with bilateral classifications into no DR (n = 144), DR/DME in one eye only (n = 45), DR in one eye and DR/DME in the other (n = 164), and DME in both eyes (n = 37). Vision-related quality of life was assessed using the composite Rasch-transformed score of the Impact of Visual Impairment (IVI) questionnaire.
Results: For unilateral better-eye classifications, multivariable linear models revealed a 9% reduction in VRQoL for any DR (β [95% confidence interval (CI)], -0.44 [-0.86, -0.03]) and a 17% reduction for any DME (-0.81 [-1.53, -0.08]) compared to individuals with no DR/DME. Bilateral categorizations revealed significant decrements in VRQoL that occurred only when both eyes had either DR or DME (11%), which worsened when both eyes were affected by DME (22%).
Conclusions: Our results suggest that interventions to prevent the onset of DR and/or DME in the second eye are strongly recommended to significantly reduce the bilateral impact of these conditions on VRQoL.