Subretinal fibrosis occurrence according to macular neovascularisation subtypes in neovascular age-related macular degeneration

Purpose: To assess subretinal fibrosis (SF) occurrence in neovascular age-related macular degeneration (nAMD), according to macular neovascularisation (MNV) subtypes. Methods: A Retrospective national multi centre cohort study included eyes with naive nAMD. Main outcome measures were, according to MNV subtypes, cumulative incidence for SF, risk factors, and best corrected visual acuity (BCVA) for 36 months. Results: Four hundred and twenty eyes were included. Cumulative incidence of SF was 34.3% at 1 year, 39.0% at 2 years and 50.6% at 3 years. In multivariable analysis, Type 2 and mixed type 1 and 2 MNV were associated (p < 0.001) with a more frequent and rapid development of SF (respectively 85.5% and 81.0% at 1 year, then 95.8% and 93.1% at 3 years) than Types 1 and 3 (respectively 11.3% and 3.6% at 1 year, then 22.9% and 12.7% at 3 years). In Type 2 and mixed type 1 and 2 MNV combined, at baseline a worse BCVA (p = 0.02) and a higher maximal subretinal hyperreflective material (SHRM) thickness (p = 0.005) were associated with SF development at 3 years. In Type 1 MNV, the presence at baseline of intraretinal fluid (IRF) (p = 0.007) or SHRM (p < 0.001) and a higher percentage of visits with IRF (p < 0.001) or with SHRM (p < 0.001) were associated with SF occurrence. For Type 3 MNV, only a higher percentage of visits with SHRM (p = 0.001) was associated with SF. Including all MNV subtypes, eyes with a worse BCVA at baseline were associated with SF development (p < 0.001). Conversely, presence of SF at 3 years was associated with a worse baseline BCVA (p < 0.001). Conclusion: Occurrence of SF differs when considering apart MNV subtypes.