An observational clinical study of the influence of phacoemulsification on choroidal neovascular membrane activity in age related macular degeneration

BACKGROUND: Thousands of phacoemulsification surgeries are performed on eyes with age-related macular degeneration (AMD) complicated by choroidal neovascular membrane (CNV) in the United Kingdom each year. As populations age this number is expected to rise. Controversy over phacoemulsification’s influence on CNV activity limits the information which clinicians and these patients use to decide on surgery. This observational study aims to resolve this controversy by reporting on intravitreal injection (IVI) frequency as a pragmatic marker of CNV activity in a large cohort. METHODS: A cohort of eyes with AMD complicated by CNV (n = 327) that underwent cataract surgery at a single tertiary centre from 2014 to 2019 were identified. These cases were matched by interval since CNV diagnosis at a specified ‘time zero’ within the follow-up of pseudophakic eyes with AMD (n = 327). Data concerning demographics, visual acuity (VA) and intravitreal injection frequency before and after ‘time zero’/phacoemulsification were collected. RESULTS: Following ‘time zero’/phacoemulsification’ the mean reduction in annual IVI frequency was 0.6 injections/year (95% CI 0.4,0.9) and 0.4 injections/year (95% CI 0.1,0.7) in the comparison and phacoemulsification cohorts respectively. The mean VA gain 12 months after phacoemulsification in the intervention cohort was 11.3 (95% CI 9.2,13.4) early treatment of diabetic retinopathy study (ETDRS) letters, with 214 eyes (65.4%) having gained ≥5 ETDRS letters after surgery. CONCLUSIONS: Phacoemulsification has no clinically significant impact on the activity of pre-existent CNV secondary to AMD. Phacoemulsification should be offered to patients with AMD and cataract that limits vision, regardless of CNV activity.