VISUAL AND SAFETY OUTCOMES OF POSTERIOR-CHAMBER PHAKIC IMPLANTABLE COLLAMER LENSES FOR LOW VS HIGH MYOPIA: AN EIGHT-YEAR RETROSPECTIVE STUDY

This study aimed to evaluate the efficacy and safety of Implantable Collamer posterior chamber phakic refractive lenses (EVO and EVO+ ICLs, STAAR Surgical Inc.) with a central port design for the correction of low (<-6D) versus high (>-6D) myopia, with or without astigmatism.

Single-center study

A retrospective study was conducted on patients receiving EVO/EVO+ ICLs (spherical or TORIC) between 2016 and 2023 in Toronto, Canada. The study population was categorized into two groups: low (< -6 D) and high myopia (> -6 D), based on preoperative manifest refraction spherical equivalent (MRSE). Outcome measures included uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), spherical equivalent (SE), intraocular pressure (IOP), endothelial cell density (ECC), ICL vault, and adverse events.

A total of 548 eyes were included, with a mean follow-up of 6.0 ± 7.4 months. The low myopia group (107 eyes, mean age 30.0 years) and high myopia group (441 eyes, mean age 29.7 years) were compared. Significant reductions in MRSE were observed in both the low (-4.42 ± 1.12 D baseline to -0.06 ± 0.30 D at follow-up) and high myopia groups (-9.73 ± 2.34 D to -0.05 ± 0.35 D; p<0.0001). In the low myope group, mean UDVA was 0.02 ± 0.06 logMAR (low myope), with 96.0% achieving within -/+0.50D of target in both groups. Comparatively, in the high myope group, the mean UDVA was 0.03 ± 0.07 logMAR, with 97.3% achieving within -/+0.50D of target in both groups. Efficacy and safety indices were favorable in both the low myope (0.98 ± 0.09 and 1.01 ± 0.08) and high myope (1.00 ± 0.13 and 1.04 ± 0.12) groups, respectively. Notably, 98.2% of low myopic and 92.8% of highly myopic eyes were within one line of their CDVA, in favour of high myopia (low: 1 eye gained, 1 eye lost; High: 31 eyes gained, 2 eyes lost; P<0.05). IOP and ECC remained unchanged post-operatively.

This study demonstrates the safety and efficacy of ICL surgery for both low and high myopia. Notably, ICL implantation was associated with significant improvements in BCVA, particularly with increasing degrees of myopia.