Clinical Study of Toric Intraocular Lens Implantation Based on Total Corneal Astigmatism

Abstract

Objective: We compared the clinical outcomes of toric intraocular lens (IOL) implantation for treating age-related cataracts associated with either total corneal astigmatism or anterior corneal astigmatism. Methods: In this retrospective clinical control study, 141 patients with age-related cataracts and corneal astigmatism were recruited and divided into an observation group (75 patients, 90 eyes) and a control group (66 patients, 81 eyes). The observation group was established based on a total corneal astigmatism of 3 mm in diameter, and the control group was established based on an anterior corneal astigmatism of 3 mm in diameter. The uncorrected distance vision acuity (UCDVA), residual astigmatism (RA), and IOL rotation three months after the surgery were recorded. The visual acuity was measured as the logarithm of the minimum angle of resolution (LogMAR). An astigmatism-biased subgroup and an astigmatism-unbiased subgroup were established within the observation and control groups according to whether the difference of the cylindrical lens was larger than 0.5 diopter (D) or the difference of the axial view was larger than 10° between the total and anterior corneal astigmatism. The means ± standard deviations ( ±s ) of vision acuity, spherical equivalent, axial length, corneal astigmatism, and RA were determined. Comparisons between groups were based on the independent samples t-tests. Results: Three months after the surgery, the UCDVA values of the control and observation groups were 0.10 ± 0.13 and 0.06 ± 0.12 (LogMAR), respectively. The mean IOL rotations were 5.6° ± 3.6° and 5.8° ± 3.8°, respectively. There were no significant differences between the groups (UCDVA: t=1.35, P=0.18; IOL rotations: t=0.66, P=0.51). The mean RA values for the control and observation groups were 0.63 ± 0.29 D and 0.52±0.22 D, respectively (t=2.07, P=0.04). The mean UCDVA of the astigmatism-biased subgroup was significantly better, and the mean RA was significantly lower than the corresponding values in the control group (UCDVA: t=2.54, P=0.02; RA: t=3.40, P<0.001). The mean UCDVA, RA, and IOL rotations in the astigmatism-unbiased subgroup and the control group were not significantly different. Conclusions: The clinical outcomes of toric IOL implantation for treating age-related cataracts are better for patients with total corneal astigmatism than those with anterior corneal astigmatism. Key words: cataract; intraocular lense; total corneal astigmatism