Relative position of the central hole after EVO-ICL implantation for moderate to high myopia

This study aimed to evaluate the relative position of the central hole (C_H) of EVO Implantable Collamer Lens (EVO-ICL), the pupil center (C_P), and the corneal center (C_C) after implantation of EVO-ICLs for moderate to high myopia.

Eighty-nine eyes of forty-seven patients with moderate to high myopia were evaluated. The mean preoperative spherical equivalent (SE) was - 12.58 ± 4.13D. A routine postoperative follow-up was performed within 1 ~ 12 months. Positions of the C_H of EVO-ICLs, the C_P and the C_C were recorded using a slit lamp anterior segment photography system, and their relative distances were calculated with the Visio image analysis software.

All surgeries were performed safely, and no complications were observed in follow-ups 4.3 ± 4.82 months after surgery. At the last follow-up, the safety index (postoperative CDVA/preoperative CDVA) was 1.23 ± 0.48, and the efficacy index (postoperative UDVA/preoperative CDVA) was 1.08 ± 0.31. The C_H in 85 eyes (95.51%) was superior to the C_C, with 47.19% (42/89) on the temporal side and 48.31% (43/89) on the nasal side. The C_H in 84 eyes (94.38%) was located on the temporal side of the C_P, with 56.18% (50/89) superior and 38.2% (34/89) inferior to the C_P. The C_P of 85 eyes (95.51%) was superior on the nasal side of the C_C. On the defined x-axis, the average distance from the C_H to C_C was significantly shorter than the average distance from the C_P to C_C (p < 0.001).

An imperfect match between the central hole of EVO-ICLs and the pupil center does not necessarily indicate ICL dislocation. Compared to the pupil center, the position of the central hole of EVO-ICL is closer to the corneal center.