Visual acuity level, ocular morbidity, and the better seeing eye affect sensitivity and responsiveness of the visual function index.

Abstract

To examine the relation between Visual Function Index-14 (VF-14) scores and VA by accounting for concurrent ocular comorbidities, effect of the better seeing eye (BSE), and VA before and after cataract surgery. Prospective cohort study. A total of 4335 patients with cataract who completed the VF-14 before and after cataract surgery. Collaborating clinicians provided demographic and clinical data before and after cataract surgery. Lowess curves, general linear models, and Spearman correlation coefficients were used to study the relation between the VF-14 and the VA. Scores in the VF-14 preintervention, change in VF-14 after surgery, VA before surgery, and VA change after surgery. General linear models and Spearman correlation coefficients showed a significant (P < 0.0001) association between VF-14 score and VA (measured in decimal fraction) when the preoperative VA was ≤0.5 (20/40) and no association (P > 0.4020) when the VA was >0.5 (20/40). Small VA gains (≤0.5) after surgery only led to significant gains (P < 0.0001) in functionality in patients with other ocular pathologies and whose BSE was the surgical eye. Gains in VA >0.5 had a significant (P < 0.02) effect on VF-14 change scores in most patients. The VF-14 seems to be more sensitive when the preoperative VA is <0.5 (20/40), especially in patients whose BSE is the surgical eye. The VF-14 seems responsive to increases in VA if the gains exceed 0.5. For gains <0.5, the VF-14 seems unresponsive, except for patients with other ocular pathologies in whom the BSE before and after surgery is the surgical eye.