Abstract
Purpose :
Hypertransmission defects (HTD), one feature of retinal pigment epithelial and outer retinal atrophy (RORA), visible on en face optical coherence tomography (OCT) images, have been suggested as a risk factor for progression to geographic atrophy (GA). We aimed to determine the prevalence of these HTDs in eyes with intermediate age-related macular degeneration (iAMD).
Methods :
Choroidal (64-200 µm below Bruch’s membrane) en face spectral domain OCT images (Cirrus OCT, Carl Zeiss Meditec, Dublin, CA) of consecutive iAMD patients examined in an ophthalmology clinic setting were evaluated by trained graders for the presence of HTDs. HTD’s were defined by the presence of a well-demarcated region of hyperreflectivity on the en face image of at least 80 µm in diameter, with evidence of at least some retinal pigment epithelial alteration on the corresponding B-scan as the explanation for the hypertransmission. By definition, as these were eyes with iAMD (i.e., no late AMD), none of these lesions met criteria for complete RORA or GA. Graders counted the number of HTD in each eye and also measured their greatest linear dimension (GLD).
Results :
A total of 137 eyes with iAMD from 121 subjects were identified and included in this analysis. Among this cohort, 22 eyes (16.1%) of 20 participants (16.5%) demonstrated evidence of HTD(s) on the baseline (first available) en face OCT. For this subgroup of patients with HTD, mean (±SD) age was 77.2 (10.9) years, 12 (60.0%) were female and 18 (90.0%) had unilateral HTD. Of the 22 HTD eyes, 19 (86.4%) had a single HTD lesion (mean [range] number of lesions per eye, 1.2 [1-3]). Among the 22 HTD eyes, 13 (59.1%) had a GLD ≥ 250 µm, 5 (22.7%) had a GLD ≥ 125 µm but < 250 µm, and 4 (18.2%) had a GLD ≥ 80 µm but < 125 µm. Only 14 (63.6%) of the HTD eyes fulfilled all criteria of iRORA, of which 11 had a GLD ≥ 250 µm or more.
Conclusions :
HTD are present in a significant proportion (~16%) of eyes with iAMD and they overlap partially with iRORA. If longitudinal studies confirm that HTD confer an increased risk for progression to GA, HTD may provide an efficient biomarker for identifying high-risk iAMD patients for enrollment into early intervention therapeutic trials.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.