Incidence and risk factors of fellow-eyes wet conversion in unilateral neovascular age-related macular degeneration over 15-year follow-up.

Purpose: Incidence and risk factors of fellow eye wet conversion in unilateral neovascular age-related macular degeneration (nAMD) over 15-years follow-up.

Methods: This retrospective study reviewed 593 unilateral nAMD patients with a minimum of five years up to 15 years of follow-up. The demographic data, visual acuity, fellow eye nAMD conversion rate, and the number of anti-vascular endothelial growth factor (anti-VEGF) injections in the primary eye were evaluated. Also, the nAMD-converted fellow eyes were divided into two groups based on the time of conversion (less and more than two years from the first injection in the primary eye). Based on the data types, the T-test, Chi-square, and Mann-Whitney U test were used to analyze.

Results: The total cases were 593 patients, and 248 eyes (41.82%) converted to nAMD in the mean interval of 34.92 ± 30.62 months. The males exhibited a predisposition to wet conversion at 2.54 years earlier than their female counterparts (P = 0.025). In all the converted fellow eyes, the mean age was 2.3 years higher at presentation in the group who converted within two years of follow-up in compared to eyes that converted after two years (79.82 ± 8.64 vs 77.51 ± 8.5 years, P = 0.035). Additionally, eyes converting within two years had a mean baseline LogMAR visual acuity of 0.44 ± 0.47, compared to 0.32 ± 0.41 for conversions after two years (P = 0.014).

Conclusion: This study reported that males showed a predisposition to fellow eye nAMD conversion at an earlier age. Additionally, there was a trend of faster fellow eye nAMD conversion in individuals with higher age and lower baseline visual acuity.

Key messages: What is known • Certain risk factors may make the fellow eye of neovascular age-related macular degeneration (nAMD) more likely to progress to wet conversion. • Identifying these risk factors for fellow eye wet conversion can help prevent it, potentially preserving the patient's vision quality for a longer duration. • The studies on the incidence of wet conversion in the fellow eye have yielded controversial results. What is new • During the 15-year follow-up period, nearly half (47.58%) of the fellow eyes that underwent wet conversion did so within the initial two years following the wet conversion of the first eye. • Males showed a predisposition to fellow eye nAMD conversion at an earlier age. • There was a trend of faster fellow eye nAMD conversion in individuals with higher age and lower baseline visual acuity.