Visual Acuity Outcomes after Phacoemulsification in Eyes with Good Visual Acuity before Cataract Surgery

Objective: to analyse cataract surgery outcomes and related factors in eyes presenting with good visual acuity. Subject and Methods: A retrospective longitudinal study of patients undergoing phacoemulsification between 2014 and 2018 in Moorfields Eye Hospital was conducted. Pre- and post-operative visual acuities were analysed. Inclusion criteria were age ≥40 years and pinhole visual acuity ≥6/9 pre-operatively. Exclusion criteria were no post-operative visual acuity data. The visual acuity change variable was also defined according to post-operative visual acuity being above or below the Snellen 6/9 threshold. Results: 2,720 eyes were included. The unaided logMAR visual acuity improved from 0.54 to 0.20 ( p < 0.001), the logMAR visual acuity with glasses improved from 0.35 to 0.05 ( p < 0.001), and the logMAR pinhole visual acuity improved from 0.17 to 0.13 ( p < 0.001); 8.1% of patients had Snellen visual acuity <6/9 post-operatively. Mean follow-up period was 23.6 ± 9.9 days. In multivariate analysis, factors associated with visual acuity <6/9 post-operatively were age (OR = 0.96, 95% confidence interval [CI] [0.95, 0.98], p < 0.001), vitreous loss (OR = 0.21, 95% CI [0.08, 0.56], p = 0.002), and iris trauma (OR = 0.28, 95% CI [0.10, 0.82] p = 0.02). Conclusions: Visual acuity improved significantly, although at least 8.1% of them did not reach their pinhole preoperative visual acuity. Worse visual acuity outcomes were associated with increasing age, vitreous loss, and iris trauma. The 6/9 vision threshold may not be able to accurately differentiate those who may benefit from cataract surgery and those who may not.