Relationship between retinal microstructures on optical coherence tomography and microperimetry in age-related macular degeneration

Abstract

Purpose: To determine the relationship between structural parameters of the outer retina on spectral-domain optical coherence tomography (SD-OCT) and microperimetric retinal sensitivity in early stages of age-related macular degeneration (AMD).

Design: Prospective, observational study.

Participants: Seventy-five eyes of 75 participants with early stages of AMD (drusen ≥ 125 μm, with/without pigmentary abnormalities) and 25 control participants of a similar age.

Methods: Participants underwent microperimetry testing and high-resolution SD-OCT scans. Structural parameters at 5 central points (0°, 1°, and 2.33° nasal and temporal to the fovea along the horizontal axis) corresponding to areas tested by microperimetry were compared. Structural parameters included outer segment (OS) length, thickness and elevation of the retinal pigment epithelium (RPE) band, grading of the inner-segment ellipsoid (ISe) band integrity, and presence of hyperreflective foci (HF).

Main outcome measures: Relationship between structural parameters and retinal sensitivity.

Results: Retinal sensitivity was significantly correlated with RPE elevation (P<0.001), ISe grading (P<0.001), and presence of HF (P ≤ 0.018) at all test points, but not with OS length (P ≥ 0.093) or RPE thickness (P ≥ 0.125). However, multiple linear regression analyses revealed that only ISe grading (P ≤ 0.011) and RPE elevation (P ≤ 0.030) remained significantly associated with retinal sensitivity at all points. By using a simple linear model incorporating ISe grading and RPE elevation to predict values of retinal sensitivity, the 95% limits of agreement between the predicted and the actual value was ± 3.83 dB.

Conclusions: The integrity of the ISe band and drusen-associated RPE elevation are significant independent predictors of microperimetric retinal sensitivity. Our findings imply that these 2 structural parameters may be surrogate markers of retinal function in the early stages of AMD.