Loss of OCT Outer Retinal Bands as Potential Clinical Trial Endpoints in Intermediate Age-Related Macular Degeneration

Purpose

To understand the potential utility of evaluating loss of the outer retinal bands on OCT B-scans as outcome measures for early interventional trials in age-related macular degeneration (AMD).

Design

An observational study.

Participants

Two hundred eighty eyes from 140 participants with bilateral large drusen.

Methods

All participants underwent OCT imaging, color fundus photography, and microperimetry testing at 6-monthly intervals up to 36 months. The extent of loss of the external limiting membrane (ELM), ellipsoid zone (EZ), and retinal pigment epithelium (RPE) bands on OCT was derived in the central 5-mm diameter, and within 5 equiareal sectors in the central 3.6-mm diameter where microperimetry testing was performed.

Main Outcome Measures

The potential utility of the OCT outer retinal bands was examined based on their performance at capturing longitudinal changes according to the coefficient of variation (CoV; lower values indicating better performance) and their association with visual sensitivity loss.

Results

Overall, the extent of loss of all 3 OCT bands increased significantly over time (P < 0.001), with a significant change from baseline first detected at 12 months for ELM and EZ loss and at 24 months for RPE loss (P ≤ 0.005 for all). Changes in the ELM, EZ, and RPE loss were all individually associated with change in mean sensitivity, percentage of locations showing a ≥7 decibels loss from baseline, and change in percentage of deep visual sensitivity defects at each corresponding sector tested on microperimetry (≤10 dB; P < 0.001 for all). The CoV of the rate of ELM and EZ loss was lower than RPE loss (P < 0.001 for both), and lower for EZ compared with ELM loss (P < 0.001).

Conclusions

The extent of loss of the outer retinal bands on OCT increased significantly over time in a cohort with intermediate AMD that was associated with changes in visual sensitivity, and measurements of EZ loss had the highest performance for capturing longitudinal changes. These findings highlight the potential utility of these parameters for evaluating interventions in the early stages of AMD.

Financial Disclosure(s)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.