Efficacy and Safety of Hole Implantable Collamer Lens in Comparison with Original Implantable Collamer Lens in Patients with Moderate to High Myopia.

Laser in situ Keratomileusis (LASIK) is the most commonly performed and widely accepted corneal refractive procedure. The Visian Implantable Collamer lens (ICL, STAAR Surgical), a posterior chamber phakic intraocular lens, has been reported to be very effective in correction of moderate to high myopia in patients who are unable to proceed with LASIK surgery due either high correction or thin cornea. A modified implantable collamer lens (ICL) with a central hole (diameter 0.36 mm), “Hole ICL”, was created to improve aqueous humor circulation: not only does it make the ICL implantation feasible without prior Laser peripheral iridotomy, but it also helps to reduce the incidence of cataract formation after ICL implantation because of its resultant improvement in aqueous humor circulation behind the ICL.To evaluate the efficacy and safety of the new “Hole ICL” in comparison with conventional ICL 3 months after implantation.This study was a non-inferiority trial in which both ICL models, the conventional ICL (Group A) and the new Hole ICL (Group B), were studied. Patients were divided into 2 groups, each containing 60 eyes: the conventional ICL group, requiring laser peripheral iridotomy, and the new Hole ICL group. The uncorrected distance visual acuity (UDVA) log MAR and the intraocular pressure (IOP) were recorded preoperatively, and then 1 day, 1 week, 1 month and 3 months postoperatively. Spherical aberration was measured preoperatively and 3 months postoperatively.The mean age in the conventional ICL group was 29.75±6.17 years (range 21-45 years), and 28.75±5.27 years (range 21-39 years) in the Hole ICL group. There was no pupillary block in either group. The UCVA log MAR in both groups showed statistically significant improvement 3 months postoperatively compared with preoperative log MAR, but there was no statistically significant difference between the log MARs of the two groups 3 months postoperatively. There was no significant change in preoperative IOP and IOP 1 day, 1 week, 1 month and 3 months postoperatively in either group, there was no difference between postoperative IOP in the two groups, and there was also no statistical significance between the spherical aberration changes in the 2 groups 3 months postoperatively.The two groups had similar clinical effectiveness in terms of unaided visual acuity, best corrected visual acuity, intraocular pressure and spherical aberration induction. The new Hole-ICL group (Group B) needed no preoperative laser peripheral iridotomies or intraoperative iridectomy.