Assessment of optical coherence tomography biomarkers in patients with non-neovascular age-related macular degeneration (AMD) converting to exudative AMD according to the status of the fellow eye.

Objectives: To compare optical coherence tomography (OCT) biomarkers in eyes converting from non-neovascular (nnAMD) to exudative age-related macular degeneration (eAMD) based on the status of fellow eye.

Methods: Retrospective analysis of one year of pre-conversion data of fellow eyes of patients with nnAMD and eAMD which converted to eAMD, defined as converting eyes (CE) with fellow nnAMD and CE with fellow eAMD respectively. Demographics, best corrected visual acuity (BCVA), and OCT biomarkers including drusen type, iRORA/cRORA, subfoveal ellipsoid zone (SFEZ) disruption, central macular thickness (CMT), subfoveal choroidal thickness (SFCT), Haller vascular thickness (HVT) were evaluated. Chi-square and t-tests were employed, confidence interval of 95% and p < 0.05.

Results: 72 eyes of 72 patients were included: 31 CE with fellow nnAMD and 41 CE with fellow eAMD. Mean age was 81.8 ± 9.9 years, with 62.5% females. Subfoveal iRORA was more frequent in CE with fellow nnAMD (26%) compared to CE with fellow eAMD (6%) 44 weeks before conversion (p = 0.058). SFCT and HVT were higher in CE with fellow nnAMD compared to CE with fellow eAMD 19 weeks prior to conversion (213 ± 82 vs. 174 ± 63 µm, p = 0.052; 121 ± 44 vs. 104 ± 50 µm, p = 0.084 respectively). BCVA was significantly higher in CE with fellow eAMD compared to CE with fellow nnAMD every time frame (p < 0.05).

Conclusions: Although subtle distinctions, no significant differences were observed between the groups. Further research is needed to understand the influence of one eye's status on progression from nnAMD to eAMD in fellow eye.