Choriocapillaris Impairment Prior to Nascent Geographic Atrophy Development

Abstract

Purpose : To assess whether choriocapillaris (CC) loss occurs prior to the development of nascent geographic atrophy (nGA) in intermediate age-related macular degeneration (iAMD) using optical coherence tomography angiography (OCTA) imaging.

Methods : Participants were enrolled as part of a prospective, longitudinal, observational study and underwent swept-source OCTA imaging (Zeiss PlexElite) at 6-month intervals. Only participants with reliable OCTA imaging in ≥2 visits and iAMD without nGA at baseline were included. CC flow deficit percentage (FD%; compensated for shadowing artifacts) and RPE volume/height measurements were determined for the visit prior to nGA development or final visit (n-1). Linear mixed models were utilized to examine the association between CC FD% and future nGA development at a global level and at a local level, defined by 120x120 µm superpixels (Figure 1).

Results : Of 105 eyes from 62 participants, 13 eyes from 10 participants developed nGA during the follow-up period. There was no significant difference in global CC FD% at the n-1 visit between eyes that developed nGA and those that did not (P = 0.399). In contrast, CC FD% was significantly higher in superpixels that developed nGA than those that did not (P < 0.001). However, the performance of CC FD% for predicting the development of nGA (area under the receiver operating curve [AUC] = 0.83) was not significantly different to the performance using RPE height alone (AUC = 0.83) or when using both CC FD% and RPE height (AUC = 0.84; P ≥ 0.48) at the superpixel level.

Conclusions : CC flow deficits were significantly greater within local regions (superpixels) that subsequently developed nGA compared to those that did not. This did not hold true at the global level. Although CC FD% did not aid in the prediction of nGA development, these findings provide further insights into the potential patho-etiology of atrophy development.

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

 

Figure 1: (A) En face OCTA choriocapillaris slab (5-25µm posterior BM) after shadowing compensation (n-1 visit). Red tracing represents area of future nGA development. (B) Central 5mm region-of-interest. (C) FD Binarization. (D) FD% heat map. (E) Super-pixel FD% heat map. Super-pixels measure 120µm x 120µm (or 20 x 20 A-scans) each.