Comparison of long-term visual quality between multifocal and monofocal Toric IOL implantation for cataract with astigmatism

Objective

To compare the visual quality of patients with astigmatic multifocus intraocular lens (ART IOL) and astigmatic monofocus IOL (Toric IOL) after implantation.

Methods

A prospective, non-randomized, controlled study was conducted to include 72 eyes of 72 cataract patients with corneal astigmatism (1.0-2.5 D) who were scheduled to receive phacoemulsification combined with IOL implantation in Chaoju Eye Hospital of Inner Mongolia from July 2017 to October 2018.Patients were divided into ART IOL group (37 eyes) and Toric IOL group (35 eyes) according to different IOLs implanted.All patients were followed up for 1 year after surgery.The main and secondary outcome indicators were compared.The main outcome indicators included distance (5 m), intermediate (80 cm), and near (40 cm) uncorrected visual acuity and best corrected visual acuity, defocus curve, contrast sensitivity, postoperative IOL rotation and residual astigmatism, while the secondary outcome indicators included visual subjective symptoms and spectacle independence rate.The above outcome indicators were compared between the two groups.This study followed the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Chaoju Eye Hospital of Inner Mongolia (No.CJYKLL202012).Written informed consent was obtained from each patient before surgery.

Results

There was no statistically significant difference between the two groups in average uncorrected distance visual acuity and best corrected distance, intermediate and near visual acuity (all at P>0.05).The average intermediate and near visual acuity in the ART IOL group was significantly higher than that in the Toric IOL group, showing statistically significant differences (both at P<0.05).The defocus curve of the ART IOL group presented a double peak, which reached the peak at the far focus (0.0 D) and near focus (-2.5 D), respectively.The visual acuity range from 1.5 to-3.0 D was above 0.2 logarithm of the minimum angle of resolution (LogMAR), and the focus depth range was 4.5 D (1.5 to -3.0 D).The defocus curve of the Toric IOL group had only one crest, which was located at best corrected visual acuity (0.0 D).The visual acuity reached 0.2 LogMAR or above were from 1.0 to -1.0 D, and the focal depth range was 2.0 D (1.0 to -1.0 D).There was no statistically significant difference in contrast sensitivity at different spatial frequencies between the two groups in bright light, bright flashing light and dark light (all at P>0.05), while the contrast sensitivity of the ART IOL group at high dark flashing light frequency was lower than that of the Toric IOL group, showing statistically significant difference (P<0.05).In the ART IOL group and the Toric IOL group, the average residual astigmatism after surgery was (-0.47±0.51)D and (-0.49±0.42)D, respectively, with no statistically significant difference (t=0.408, P>0.05).There was no significant difference in postoperative IOL rotation between the two groups (t=1.906, P>0.05).The total postoperative spectacle independence rate in the ART IOL group was 97.30%(36/37), which was higher than that in the Toric IOL group (17.14%, 6/35), showing statistically significant difference (χ²=15.320, P<0.05).

Conclusions

Both Toric IOL and ART IOL can better correct corneal astigmatism and improve patients’ distance visual acuity, but ART IOL implantation can provide better distance, intermediate and near visual acuity, and higher spectacle independence rate.