Visual and autorefraction outcomes following toric intraocular lens insertion without calculation of posterior corneal astigmatism in the UK National Health Service

Abstract

Objective: To ascertain visual and refractive outcomes following toric intraocular lens (IOL) implantation in the UK National Health Service (NHS) without posterior corneal astigmatism calculation, with multiple surgeons of different grades, pooled input and output pathways and autorefraction as the refractive outcome measure. Methods: Preoperative and 1-month post-operative data were analysed retrospectively in 114 eyes (95 patients) receiving a toric IOL between 2014 and 2016 at Imperial College NHS Trust. Preoperative keratometric astigmatism was ≥2 dioptres (D). Results: Mean preoperative best-corrected visual acuity (BCVA) was 0.50 logMAR (±0.46), improving to a mean uncorrected VA (UCVA) of 0.35 logMAR (±0.36) postoperatively (p < 0.001) with 65% of eyes attaining a UCVA ≤ 0.30 logMAR. Excluding 33 eyes with pre-existing visual comorbidities and one targeting monovision, mean post-operative UCVA was 0.24 logMAR (±0.29) (p < 0.001), and 85% had UCVA ≤ 0.30 logMAR, 62% UCVA ≤ 0.20 logMAR. Mean refractive astigmatism improved from 3.04 D (±1.46) to 1.36 D (±1.13) (p < 0.001). In total, 52% of eyes had post-operative refractive astigmatism ≤1.00 D. The Alpins correction index was 1.05 (±0.22), indicating a tendency to overcorrect. Toric IOL misalignment was noted in two eyes, and two cases of posterior capsule rupture were converted to a non-toric IOL. Conclusions: Visual outcomes of toric IOL implantation in our pooled pathway are comparable to single-surgeon case series where posterior corneal astigmatism has not been accounted for. However, with 1-month post-operative autorefraction, only 52% of eyes had ≤1 D refractive astigmatism, which is lower than previously published series, but may be standard for 1-month autorefraction outcomes.