Association between visual acuity loss and disease pathways in the initial stages of nonproliferative retinopathy in type 2 diabetes

Abstract

Purpose : To examine the association of changes in best corrected visual acuity (BCVA) occurring in a 5-year prospective longitudinal study of eyes with mild diabetic nonproliferative retinopathy (NPDR), with the three main disease pathways: microvascular changes, neurodegeneration and edema.

Methods : 212 patients with type 2 diabetes (T2D) and mild NPDR (ETDRS grades 20 or 35) were followed in a 5-year longitudinal study. Ophthalmological examinations were performed at baseline and annually.
BCVA was measured using Snellen chart for the patients and then converted to logarithm of the minimum angle of resolution (logMAr) VA. ETDRS and severity progression was assessed in T2D individuals by grading of 7-fields CFP performed at the initial and last visits. Microaneurysm turnover (MAT) was evaluated using the RetMarkerDR. Optical coherence tomography (OCT) was performed to evaluate average thickness of the ganglion cell layer (GCL).

Results : Of the 212 individuals with type 2 diabetes (T2D) and mild NPDR, one eye per person, followed for 5 years with annual visits, 171 completed the study or developed an outcome. BCVA worsening occurred in 118 eyes (69%) during the 5-year follow-up. BCVA worsening is associated with GCL thinning in the central macular area, representing neurodegeneration (difference V6-V1, p=0.038), but did not show association with MAT (considering MAT≥6 vs MAT<6), representing microvascular changes (p=0.633) or central retina thickness, representing edema (p=0.634).
For the ones that completed the study, BCVA was also associated with age (p=0.002) and sex (p=0.055). No association was found with ETDRS level worsening.

Conclusions : BCVA worsening in eyes with mild NPDR, during a 5-year follow-up, is associated with neurodegenerative changes identified by GCL thinning in the macula, but not with the presence and progression of edema and/or ischemia.

This is a 2021 ARVO Annual Meeting abstract.