Abstract
OBJECTIVES: To determine the efficacy of toric intraocular lens (TIOL) implantation in cataract surgery patients with high levels of pre-operative corneal astigmatism and ocular co-morbidities in a state funded, National Health Service (NHS) hospital. METHODS: Retrospective cohort study involving consecutive cases of TIOL implantation in cataract surgery with over 3.00DC of pre-operative corneal astigmatism. Subjects were implanted with the Tecnis TIOL (Abbot Medical Optics) with capsular tension ring stabilisation using the Callisto system (Carl Zeiss Meditec). Visual acuity and refraction were assessed at 4-6 weeks post-operatively. Vector analysis was used to calculate the intended refractive correction, surgically induced refractive correction (SIRC), correction ratio (CR), error of magnitude (EM) and error vector (EV). RESULTS: Sixty-six eyes of forty-seven subjects aged 73.8 ± 11.9 were included. Eyes with ocular co-morbidities included dry age-related macular degeneration (n = 13), amblyopia (n = 7), high myopia (n = 7), glaucoma (n = 6), previous corneal transplantation (n = 2), nanophthalmos (n = 2) and corneal scarring (n = 1). Pre-operative corneal astigmatism was 4.25 ± 1.69DC (range 3.00-12.00), post-operative refractive astigmatism was 1.31 ± 1.05DC (range 0.00-6.50DC) and post-operative unaided visual acuity was 0.25 ± 0.19 LogMAR. Vector analysis demonstrated an SIRC of 4.08 ± 1.39DC, CR = 1.1 ± 0.3, EM -0.4 ± 1.0 and EV of 1.23 ± 0.72. CONCLUSIONS: The results demonstrate the efficacy of TIOL implantation in patients with high corneal astigmatism and provide strong evidence advocating their use in cataract surgery within a state funded hospital eye service. Refractive astigmatism was significantly lower than the pre-operative corneal astigmatism and a low error vector was achieved relative to the magnitude of correction.