Comparison of tolerance to decentration and tilt in the early postoperative period between the continuous range and bifocal intraocular lens implantation in myopic eyes

Abstract

Objective: To compare decentration and tilt tolerances between continuous range intraocular lens (IOL) and bifocal IOL in myopia during the early stages post intraocular implantation. Method: A retrospective cohort study was conducted using follow-up data of 145 patients (145 eyes) who underwent phacoemulsification combined with IOL implantation in the Eye & ENT Hospital of Fudan University from January 2018 to December 2020. According to whether the axial length was less than 24.5 mm, patients were divided into non-myopic and myopic groups. According to IOL type, patients were divided into extend depth of focus (EDOF) ZXR00 IOL group (myopic 38 eyes, non-myopic 41 eyes) and bifocal ZMB00 IOL group (myopic 23 eyes, non-myopic 43 eyes). The distance and near visual acuity (log of the minimum angle of resolution visual acuity), IOL tilt and decentration, intraocular high-order aberration (HOA), coma, trefoil, spherical aberrations, modulation transfer function (MTF), as well as VF-14 index and the incidence of dysphotopsia were compared between the 2 groups at 3 months after surgery. Statistics were performed using Student's t-test, χ2 test, Pearson correlation analysis and multiple linear regression analysis. Results: In either the myopic or non-myopic group, no significant differences were found in age, gender, eye laterality, axial length and IOL degree between eyes with the two different types of IOLs (all P>0.05). At 3 months after surgery, there was no significant difference in uncorrected and best-corrected distance visual acuity between the ZXR00 IOL group and the ZXR00 IOL group, while uncorrected near visual acuity was better in the ZMB00 IOL group than the ZXR00 IOL group (t=10.41, P<0.01). The total postoperative IOL decentration in the ZXR00 IOL group and ZMB00 IOL group in myopic eyes were (0.32±0.17) and (0.38±0.16) mm, respectively, which were greater than those in non-myopic eyes [(0.22±0.12), (0.28±0.12) mm; t=3.16, 2.57; both P<0.05]. However, there were no significant differences in IOL tilt between myopic and non-myopic eyes in the 2 groups (both P>0.05). There were no significant differences in postoperative IOL tilt and decentration between the 2 groups regardless of myopia or non-myopia (all P>0.05). In myopic eyes, HOA, coma aberration and spherical aberration in the ZXR00 IOL group were significantly lower than those in the ZMB00 IOL group, while the total ocular MTF (38.15±10.12) was significantly higher than that in the ZMB00 IOL group (30.46±10.53) (all P<0.05). Pearson correlation analysis and multiple linear regression analysis showed a positive correlation between postoperative HOA and both IOL tilt and decentration in the ZMB00 IOL group (r=0.627, 0.726; β=0.446, 0.587; all P<0.01). However, no such relationship was found in the ZXR00 IOL group (all P>0.05). In myopic eyes, when the IOL tilt aberration and decentration were greater than the median, the HOAs in the ZXR00 IOL group [(0.33±0.14), (0.27±0.11) μm] were lower than those in the ZMB00 IOL group [(0.88±0.56), (0.96±0.45) μm], while the total ocular MTF (42.87±10.97, 40.22±9.30) were higher than those in the ZMB00 IOL group (25.02±8.99, 29.87±10.19) (all P<0.05). In myopic eyes, the proportion of patients with visual interference symptoms in the ZXR00 IOL group [42.11% (16/38)] was significantly lower than that in the ZMB00 IOL group [78.26%(18/23), χ²=7.59, P<0.05]. Conclusion: During the early stages after IOL implantation in myopic eyes, EDOF IOL is more tolerant to decentration and tilt than bifocal IOL.