Visual field changes in diabetic retinopathy: natural history and after pan-retinal photocoagulation in the Diabetic Retinopathy Study (DRS) and the Early Treatment Diabetic Retinopathy Study (ETDRS).

Abstract

Objective: To examine visual field changes in untreated diabetic retinopathy (DR) and compare them to those in DR treated with pan-retinal photocoagulation (PRP).

Design: Post-hoc analyses of the Diabetic Retinopathy Study (DRS) and Early Treatment Diabetic Retinopathy Study (ETDRS), historical multicenter randomized controlled trials designed to assess the use of argon laser PRP as a treatment for DR.

Participants: A total of 1660 DRS eyes (830 participants) with severe non-proliferative diabetic retinopathy (NPDR) or proliferative diabetic retinopathy (PDR), and 5416 ETDRS eyes (2708 participants) with mild-severe NPDR or early PDR.

Methods: Each DRS and ETDRS participant had one eye randomized to immediate PRP and the fellow eye to deferred PRP. Visual field scores (VFS) were obtained with the Goldmann perimeter using the IV/4e stimulus in the DRS and the I/4e stimulus in the ETDRS. Eyes in the deferred PRP arm that later received PRP were censored at treatment initiation.

Main outcome measures: The outcomes of (1) mean VFS and (2) change from baseline VFS over time were estimated by using multivariable regression models with repeated measures.

Results: Among untreated eyes (n=830 [DRS], n=2706 [ETDRS]), VFS change from baseline was -152.0 (95% CI -215.4, -88.5) at 6 years (DRS) and -79.2 (-90.9, -67.6) at 7 years (ETDRS). Compared with untreated eyes with NPDR, untreated eyes with PDR + high-risk characteristics (HRC) had VFS change of -50.2 (-65.9, -34.6) and -38.3 (-69.2, -9.5) in the DRS and ETDRS, respectively. Among untreated eyes, the presence of macular edema (ME) was associated with a VFS change of -12.9 (-25.4, -0.5) and -6.2 (-10.4, -1.9) in the DRS and ETDRS, respectively. The difference in VFS between PRP-treated versus untreated eyes was significant at 4 months [-31.4 (95% CI -38.6, -24.2)], but no longer apparent by year 3 [-1.4 (-17.0, 14.1)] in the paired DRS analyses.

Conclusions: The natural history of untreated DR involved a significant decline over time in visual fields. Increased DR severity and presence of ME were associated with greater field loss. PRP was associated with a rapid initial decline in the visual field; however, visual fields in PRP-treated versus untreated eyes became similar by year 3.