[Safety and efficacy of aspheric phakic IOL implantation in myopia: short-term clinical results]

Objective: To evaluate the clinical safety and efficacy of aspheric phakic intraocular lens (PIOL) implantation for myopia correction. Methods: This prospective, multicenter, single-blind (patient-masked), randomized, controlled clinical trial was conducted from March 2019 to April 2022 across nine ophthalmic centers (including the Eye & ENT Hospital of Fudan University and Beijing Tongren Hospital, Capital Medical University). Eligible myopic patients scheduled for PIOL implantation were randomly assigned via a centralized dynamic randomization system to receive either the experimental aspheric PR PIOL or the control V4c implantable Collamer lens. At postoperative 1, 3, and 6 months, the efficacy index (primary endpoint: proportion achieving≥0.8 at 6 months), safety index, uncorrected distance/near visual acuity, best-corrected distance visual acuity, vault, intraocular pressure, corneal endothelial cell density, visual symptoms, and complications of the two groups were compared, with statistical analyses using the independent t-tests and chi-square tests. Results: The study enrolled 187 myopic patients (187 eyes), including 47 males (47 eyes) and 140 females (140 eyes), with a mean age of (28.60±5.08) years (range: 25 to 32 years). The experimental group included 91 patients, while the control group included 96 patients. At 6 months postoperatively, the efficacy index was 1.12±0.24 and 1.14±0.21, and the safety index was 1.28±0.26 and 1.26±0.23 in the experimental group and the control group, respectively, with no statistically significant differences between the two groups (both P>0.05). The difference in primary endpoint achievement rates was -1.19% [98.81% (83/84) in the experimental group vs. 100% (86/86) in controls], which exceeded the non-inferiority margin of -10%, demonstrating non-inferiority of the experimental intervention. At 6 months, the experimental group demonstrated uncorrected distance visual acuity of -0.01±0.09 logMAR compared to -0.03±0.08 logMAR in the control group, while best-corrected distance visual acuity was measured at -0.06±0.07 logMAR versus -0.08±0.06 logMAR, with no statistically significant differences observed between groups (both P>0.05). Similarly, there were no statistically significant intergroup differences in intraocular pressure and corneal endothelial cell density (both P>0.05). At both 1 month and 6 months postoperatively, the differences were significant between the two groups in the central vault and the peripheral-central vault difference (all P<0.05); however, no statistically significant difference in the peripheral vault was observed between groups (both P>0.05). At 1 month postoperatively, the incidence of glare in the experimental group [24.72% (22/89)] was significantly lower than that in the control group [54.26% (51/94)] (P<0.05). And there were no statistically significant differences between the two groups in the incidence of other visual symptoms including diplopia, ghosting, and blurred vision (all P>0.05). During the 6-month follow-up period, neither group exhibited any postoperative complications. Conclusion: Aspheric PIOL implantation shows favorable 6-month safety/efficacy and visual quality in myopia correction, though long-term outcomes warrant further investigations.