Efficacy and safety of posterior chamber Ejinn phakic refractive lens for ultra-high myopia

The aim of the present study was to investigate the efficacy and safety of posterior chamber Ejinn Phakic Refractive Lens (EPRL) for patients with ultra-high myopia. A total of 51 eyes from 26 patients with ultra-high myopia underwent EPRL implantation at Zhongshan Ophthalmic Center (Guangzhou, China) between July 2021 and November 2022, were enrolled in this retrospective study. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refractive errors, anterior chamber depth (ACD), and corneal endothelial cell density were measured before and after surgery. The efficacy index (postoperative UDVA/ preoperative CDVA), safety index (postoperative CDVA/preoperative CDVA), and factors influencing postoperative vault, and EPRL position through anterior segment optical coherence tomography were analyzed. Inter-eye correlation was addressed using generalized estimating equation (GEE) models. Multiple linear regression analysis adjusted for age, gender, EPRL model, EPRL diopter, lens thickness, postoperative ACD, and anterior chamber width was used to evaluate factors associated with postoperative vault, decentration, and tilt of EPRL. The mean age of these 26 patients (five male and 21 female) who underwent EPRL implantation was 30.27 ± 7.76 years. The mean preoperative and postoperative UDVA was 0.04 ± 0.03 (0.01−0.12), and 0.50 ± 0.23 (0.10−1.00). The mean preoperative and postoperative CDVA was 0.55 ± 0.29 (0.15−1.00), and 0.70 ± 0.26 (0.30−1.00). UDVA and CDVA were higher than those before surgery (<italic>p</italic> &lt; 0.05). The efficacy index was 1.00 ± 0.51 and the safety index was 1.44 ± 0.45. The endothelial cell density was 2976.82 ± 306.38 preoperationly, and 2854.43 ± 335.693 postoperationly. The rate of endothelial cell loss was 3.98% (<italic>p</italic> = 0.057). The mean vault was 313.75 ± 217.29 μm. Vault was related to gender (male, <italic>β</italic> = 0.51; 95% confidence interval [CI], 0.16 to 0.84; <italic>p</italic> = 0.014), larger diameter EPRL model (BK113, <italic>β</italic> = 0.56; 95% CI, 0.18 to 0.87; <italic>p</italic> = 0.014), and EPRL diopter (<italic>β</italic> = 0.39, 95% CI, 0.04 to 0.71; <italic>p</italic> = 0.032), and lens thickness (<italic>β</italic> = −0.40, 95% CI, −0.72 to −0.08; <italic>p</italic> = 0.023). EPRL horizontal decentration was related to gender (male, <italic>β</italic> = 0.42; 95% CI, 0.12 to 0.72; <italic>p</italic> = 0.036), smaller diameter EPRL model (BK108, <italic>β</italic> = −0.35; 95% CI, −0.61 to −0.09; <italic>p</italic> = 0.036), anterior chamber width (<italic>β</italic> = 0.52; 95% CI, 0.16 to 0.89; <italic>p</italic> = 0.036), and postoperative ACD (<italic>β</italic> = −0.79; 95% CI, −1.41 to −0.17; <italic>p</italic> = 0.039). Severe complications were not detected at a mean follow-up period of 9.75 ± 6.88 months. EPRL demonstrated effective correction of ultra-high myopia with relative safety in the short term. The postoperative position of EPRL exhibited a significant correlation with gender, EPRL model, and anterior chamber parameters.