Choroidal imaging biomarkers as predictors of conversion to exudative age-related macular degeneration.

Purpose: Predicting the progression of intermediate AMD (iAMD) to neovascular AMD (nAMD) will help to identify high-risk patients and improve treatment outcomes. The present study assessed whether choroidal OCT biomarkers could predict conversion to nAMD.

Methods: This retrospective study included patients with clinically stable iAMD who either converted to nAMD (C group) or did not convert (NC group) during one year of follow-up. OCT parameters included subfoveal choroidal thickness (SFCT), central macular thickness (CMT), Haller vascular thickness (HVT), inner choroidal thickness (ICT), and double-layer sign (DLS).

Results: Of 116 total eyes, there were 37 in the NC group and 79 in the C group. Baseline SFCT was significantly lower in the C group compared to the NC group (169.0 ± 63.2 μm vs. 218.0 ± 97.8 μm, p = 0.01). Baseline HVT and ICT were lower in the C group (105.2 ± 40.6 μm vs. 121.0 ± 56.6 μm, p = 0.17 and 61.9 ± 35.5 μm vs. 77.5 ± 41.7 μm, p = 0.09). HVT was decreased at all time points in the C group vs NC (p > 0.05). The ICT was reduced in the C group at each time point except at conversion time (p > 0.05). Of all eight eyes who presented DLS at baseline, 100% converted to nAMD (p < 0.001).

Conclusion: Lower SFCT at baseline may signal conversion to nAMD within 12 months.