Determination and evaluation of efficacy and rotational stability of two toric intraocular lenses

Objective

To objectively evaluate the postoperative efficacy and rotational stability of two common types of toric intraocular lenses (IOLs), and perform vector analysis of postoperative residual astigmatism.

Methods

A cohort study was performed.A total of 80 cases (80 eyes) of age-related cataract combined with corneal regular astigmatism patients who underwent phacoemulsification combined with toric IOL implantation in Ningbo Aier Guangming Eye Hospital from January 2019 to October 2021 were selected.The astigmatic corrected IOL was implanted according to the patients’ wishes.Among them, 39 cases (39 eyes) implanted with Tecnis^® ZCT IOL were classified as Tecnis group, and 41 cases (41 eyes) implanted with AcrySof^® IQ Toric IOL were classified as AcrySof group.The uncorrected distance visual acuity (UCDVA), best corrected distance visual acuity (BCDVA), and residual astigmatism of subjective refraction were observed 1 week, 1 month, and 3 months after operation.After mydriasis, OPD-Scan Ⅲ was used to measure the toric IOL axial position, and the IOL axial deviation (LAD) was calculated.Vector analysis of preoperative corneal astigmatism, expected residual astigmatism and postoperative residual astigmatism was performed using the astigmatism double-angle map.The study protocol was approved by the Ethics Committee of Ningbo Aier Guangming Eye Hospital (No.2019-001).

Results

There was no significant difference in the overall comparisons of UCDVA and BCDVA between the two groups (H_group=2.503, P=0.113; H_group=0.399, P=0.527), while there were statistically significant differences between before and different time points after operation (H_time=147.535, P<0.001; H_time=146.808, P<0.001). Postoperative UCDVA and BCDVA were significantly improved compared to preoperative, and the difference was statistically significant (all at P<0.001). There were statistically significant differences in the overall comparison of astigmatism between the two groups before and at different time points after operation (H_group=5.489, P=0.019; H_time=171.070, P<0.001). The residual astigmatism was significantly higher in AcrySof group than in Tecnis group 1 month after operation (P=0.016), and the residual astigmatism after operation in both groups decreased compared to before operation, showing statistically significant differences (both at P<0.001). There was no statistically significant difference in IOL LAD between the two groups at different time points after operation (H_group=3.013, P=0.083; H_time=1.689, P=0.430). Vector analysis of astigmatism showed that residual astigmatism was significantly reduced in both groups at 3 months after operation compared to before operation, and the 95% confidence ellipses were significantly reduced.There were differences in the mean and centroid values of residual astigmatism prediction errors between the two groups 3 months after operation, but there was no significant difference in the 95% confidence ellipse.The percentage of eyes with residual astigmatism prediction error ≤1.0 D in Tecnis group and AcrySof group was 82%(32/39) and 90%(37/41), respectively, showing no statistically significant difference (χ²=1.131, P=0.288).

Conclusions

Both Tecnis^® ZCT IOL and AcrySof^® IQ Toric IOL can effectively improve postoperative visual acuity of patients with cataract and corneal astigmatism, reduce postoperative residual astigmatism and have good rotational stability.The online calculators of the two types of toric IOLs have good performance in the prediction of postoperative residual astigmatism.

Cataract; Lenses, intraocular; Treatment outcome; Residual astigmatism; Rotational stability; Vector analysis