Does outer retinal layer thickness correlate with the central visual field indices in early dry age-related macular degeneration?

Abstract

PURPOSE: Age-related macular degeneration (ARMD) is the leading cause of irreversible blindness worldwide and Nepal is one among them. We aimed to determine the relationship between outer retinal layer thickness parameters with central visual field indices in early dry ARMD cases among Nepalese population. MATERIALS AND METHODS: The subjects for this descriptive, cross-sectional study comprised 40 patients with early dry ARMD from the ophthalmology department of a tertiary level hospital of Nepal. The retinal layer thickness was measured with spectral-domain optical coherence tomography (SD-OCT), and the visual field indices were assessed using the 10-2 protocol of Humphrey visual field analyzer (HFA). Thus, the retinal layer structures correlated with visual field indices among our population. RESULTS: Among our early dry ARMD population, the foveal threshold (FT) was found to be significantly correlated with retinal pigment epithelium (RPE) elevation (P < 0.01, r = −0.541), outer segment (OS) length (P = 0.02, r = 0.465), and inner segment ellipsoid (ISe) band disruption (P = 0.01, r = −0.499), but not with presence of hyperreflective foci (P = 0.464), RPE thickness (P = 0.612), and central macular thickness (P = 0.214). However, no significant correlation between mean deviation and pattern standard deviation of visual field with retinal layer thickness parameters was identified. CONCLUSION: In early dry ARMD, a reduced FT is significantly correlated with the integrity of the ISe band, thinning of OS length, and drusen-associated RPE elevation. The results highlight the utility of both SD-OCT retinal layer measurement and central visual field testing by HFA in ARMD to monitor the progression of the disease.

Keywords

• age-related macular degeneration
• microperimetry
• nepal
• retinal layer thickness
• visual field indices