Purpose: To evaluate the changes in iridocorneal angle structure and trabecular pigmentation after implantation with the STAAR Implantable Collamer Lens (ICL), as potential risk factors of secondary glaucoma.
Methods: An ICL was implanted in 48 eyes of 29 patients with high myopia. Angle opening distance (distance between trabecular meshwork and iris) measured at 500 microm from the scleral spur and trabecular-iris angle were assessed preoperatively and at 1, 6, 12, and 24 months postoperatively by ultrasound biomicroscopy, and trabecular pigmentation was evaluated preoperatively and at 1, 12, and 24 months postoperatively by standardized gonioscopic photography.
Results: Mean follow-up was 33.2 +/- 7.3 months. One-month postoperative trabecular-iris angle and angle opening distance values were significantly smaller than preoperative values by 41.5% and 31.8%, respectively (P < .001), but no significant progressive changes were observed thereafter. The mean trabecular pigmentation of four quadrants did not change significantly during the first month after ICL implantation (P = .317), but significantly decreased at 1 and 2 years postoperatively compared with the preoperative value (P = .039 and .047, respectively). Intraocular pressure (IOP) remained stable in all eyes throughout follow-up except in one eye, which showed elevated IOP and significantly increased trabecular pigmentation requiring antiglaucoma medications.
Conclusions: No ongoing narrowing of iridocorneal angle was noted after approximately 40% narrowing at 1 month postoperatively. There was no general increase in trabecular pigmentation or IOP over a mean follow-up of 33.2 months. Considering significant initial angle crowding and one eye with increased trabecular pigmentation and IOP, careful monitoring of iridocorneal angle and IOP is required during the early postoperative period, especially for 1 month.