Toric Versus non-toric intraocular lenses for pre-existing corneal astigmatism: a systematic review and meta-analysis

Background Preoperative corneal astigmatism is prevalent among cataract patients and has a negative effect on uncorrected distance visual acuity. Toric IOLs are commonly used to correct astigmatism and clinical trials and expert consensus have reported advantages as compared to non-toric IOLs, but the degree and the consistency of these improvements remain to be more clearly defined. Methods Clinical studies comparing toric and non-toric IOL implantation in cataract patients with corneal astigmatism were identified in PubMed and Web of Science. The primary outcome was postoperative residual refractive astigmatism; secondary outcomes were UDVA, corrected distance visual acuity, the proportion of eyes with residual refractive cylinder ≤ 0.5 D, and postoperative spherical equivalent. Effect estimates were pooled as standardized mean differences, mean differences or odds ratios along with 95% confidence intervals. Results A total of twelve studies qualified for inclusion. Toric IOLs yielded lower residual refractive astigmatism (SMD = −1.03, 95% CI −1.16 to −0.90) and better UDVA (SMD = −0.91, 95% CI −1.07 to −0.76) than non-toric IOLs. More eyes with toric IOLs achieved residual cylinder ≤ 0.5 D (OR = 3.31, 95% CI 2.44 to 4.48). The differences in spherical equivalent were small (MD = 0.07 D, 95% CI 0.02 to 0.13) and are likely to be of limited clinical relevance. Conclusions In patients with corneal astigmatism, toric IOLs provide more precise astigmatic correction and better uncorrected distance vision. These pooled effect sizes refine the current consensus and may assist refractive planning in cataract surgery.