Refractive outcomes following low astigmatism correction guided by toric calculator recommendations

To examine refractive outcomes after cataract extraction with a toric correction of 1.0 diopter as recommended by the Barrett Toric Calculator.

Retrospective analysis of patients who underwent cataract surgery in two tertiary medical centers with a toric intraocular lens (IOL) providing a 1.0 diopter correction in the IOL plane. Electronic patient charts were screened for preoperative and postoperative data, including visual acuity, subjective refraction, biometry measurements, and corneal tomography. Refractive outcomes were compared to a control group with low astigmatism who had undergone cataract extraction with a non-toric monofocal lens and another group with high-toric IOLs.

Twenty-six eyes with low-toric IOLs (LT) were compared to 28 non-toric monofocal IOLs (NT) and 47 high-toric IOLs (HT). The trimmed (tr) mean centroid prediction error in refractive astigmatism (RA) was similar between LT and HT groups (0.08D@1.3° vs. 0.11D@93.0°, p  =  0.24), as was the postoperative RA centroid (0.09D@109.8° vs. 0.2D@93.9°, p = 0.1). The LT group had a lower tr-mean centroid and absolute postoperative RA than the NT group (0.09D@09.8° vs. 0.49D@175.7°, p<0.001, 0.29D vs. 0.84D, p = 0.001). Simulation showed improved outcomes with low-toric IOLs in the NT group: lower centroid astigmatism (0.11D@35.1°, p = 0.001) and lower absolute residual astigmatism (0.54D, p = 0.009).

Correction of 1.0 diopter in the IOL plane demonstrates comparable accuracy and precision to higher astigmatism correction with toric IOLs, with potentially favorable refractive outcomes compared to patients eligible for this correction but fitted with monofocal non-toric IOLs.