Patient-tailored Microperimetry Grids for Focal Lesions in Intermediate AMD: A PINNACLE Study Report

Abstract

Purpose : Standard microperimetry grids may underestimate the effect of focal lesions on retinal sensitivity. This study tested the hypothesis that patient-tailored microperimetry grids improve the assessment of focal lesions in individuals with intermediate age-related macular degeneration (iAMD).

Methods : In the longitudinal, prospective, multicenter PINNACLE study, patients underwent standardized microperimetry testing (24 points covering the macula). Incident focal events (FEs, including focal drusen regression, ellipsoid zone/interdigitation zone (EZ/IZ) loss with hypertransmission, and new onset intra- or subretinal fluid) were diagnosed by optical coherence tomography in an automated way. They triggered additional testing with a targeted 5-point focal grid (Fig. 1). To date, 28 eyes from 26 patients experiencing a total of 34 FEs were analyzed. To impute the local sensitivity before the incident FE, we applied generalized additive models. A linear mixed model was used to compare the longitudinal change in retinal sensitivity measured with focal grids against the change (at the same location) imputed from the standard grids.

Results : The large 24-point grids underestimated sensitivity loss in cases of EZ/IZ loss with hypertransmission by 1.20 dB (SE = 0.30 dB, p < 0.0001) compared to the 5-point focal grids. Furthermore, EZ/IZ loss with hypertransmission caused a significant sensitivity loss of 1.99 dB (SE = 0.61 dB, p < 0.05) in the affected retinal area. Notably, the impact of focal drusen regression and subretinal fluid on retinal sensitivity was not significant. Accordingly, underestimation of retinal sensitivity loss measured by 24-point grids was not apparent for these lesions.

Conclusions : The study demonstrates the utility of patient-tailored focal grids in capturing finer details of retinal sensitivity changes compared to standard 24-point grids. Specifically, EZ/IZ loss with hypertransmission emerges as a critical factor contributing to sensitivity loss in iAMD. These findings highlight the importance of incorporating focal grids in MP assessments to better understand the progression of retinal function loss in AMD.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.

 

Fig. 1: A: 24-point microperimetry grid as measured at baseline and after focal events. B: Two 5-point focal grids measured at the locations of focal events.