Consensus Grading of Persistent Hyper-Transmission Defects on En Face OCT Imaging of Age-Related Macular Degeneration

Abstract

Purpose : A training exercise was performed using en face optical coherence tomography (OCT) images to study the ability of graders to reliably identify persistent choroidal hyper-transmission defects (hyperTDs), also known as complete retinal pigment epithelium and outer retinal atrophy (cRORA).

Methods : Formal training on how to identify persistent hyperTDs on en face OCT images was provided to 11 graders. Persistent hyperTDs were defined as bright, well-delineated lesions having a greatest linear dimension (GLD) of at least 250 μm. Training consisted of a tutorial session followed by the grading of three pretest exercises, each consisting of three cases. After all the graders scored 100% on the pretest exercises, they evaluated a final test set consisting of 30 en face OCT images from 29 eyes with non-exudative age-related macular degeneration (AMD). These images contained 107 hyperTDs, as determined by a senior author (P.J.R.) and represented a variety of AMD-related atrophic lesions.

Results : A total of 1177 hyperTDs from 30 en face OCT images were reviewed by the graders. The mean sensitivity, PPV, and modified accuracy for all the graders were 99.0%, 99.2%, and 98.2%, respectively. There was a 97% agreement observed between all the graders (AC₁ = 0.97). Internal graders from the Bascom Palmer Eye Institute had a slightly higher agreement compared with the external graders (AC₁ = 0.98 vs. 0.96). The hyperTDs most often incorrectly identified included the following features: (1) hyperTDs containing a hypo-transmission defect (hypoTD) core, (2) single hyperTDs that were incorrectly graded as two separate lesions, and (3) hyperTDs with a borderline GLD close to 250 μm.

Conclusions : The accurate detection of persistent hyperTDs on en face OCT images by graders demonstrates the feasibility of using this OCT biomarker to identify disease progression in eyes with non-exudative AMD. Thus, hyperTDs can represent a clinical trial endpoint in studies designed to test new therapies that may slow disease progression from intermediate AMD to cRORA.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.

 

Figure 1. A case from the pretest exercise showing persistent choroidal hyper-transmission defects (hyperTDs). En face swept-source OCT (SS-OCT) sub-RPE structural images (A-C) and corresponding color-coded B-scans (D-I). Red circles represent the lesions that met the criteria for a persistent hyperTD and needed to be identified by the graders.