Visual Field Changes in Diabetic Retinopathy: Natural History and after Pan-Retinal Photocoagulation in the Diabetic Retinopathy Study and the ETDRS.

OBJECTIVE

To examine visual field (VF) 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 DR Study (DRS) and ETDRS, historical multicenter randomized controlled trials designed to assess the treatment effects of argon laser PRP for DR.

PARTICIPANTS

A total of 1660 DRS eyes (830 participants) with severe nonproliferative DR (NPDR) or proliferative DR (PDR), and 5416 ETDRS eyes (2708 participants) with mild-severe NPDR or early PDR.

METHODS

Each DRS and ETDRS participant had 1 eye randomized to immediate PRP and the fellow eye to deferred PRP. Visual field scores (VFSs) 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 mean VFS and change from baseline VFS over time were estimated with multivariable regression models with repeated measures.

RESULTS

Among untreated eyes (n = 830 [DRS] and n = 2,706 [ETDRS]), VFS change from baseline was -152.0 (95% confidence interval [CI], -215.4 to -88.5) at 6 years (DRS) and -79.2 (-90.9 to -67.6) at 7 years (ETDRS). Compared with untreated eyes with NPDR, untreated eyes with PDR + high-risk characteristics had VFS change of -50.2 (-65.9 to -34.6) and -38.8 (-69.2 to -8.5) 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 to -0.5) and -6.2 (-10.4 to -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 to -24.2]), but no longer apparent by year 3 (-1.4 [-17.0 to 14.1]) in the paired DRS analyses.

CONCLUSIONS

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

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