Impacts of Implantable Collamer Lens V4c Placement on Angle Measurements Made by Optical Coherence Tomography: Two-Year Follow-up.

Abstract

To determine iridocorneal angle changes produced after 2 years of implantable collamer lens (ICL) V4c (STAAR Surgical AG, Nidau, Switzerland) placement by Fourier-domain optical coherence tomography (FD-OCT). Prospective interventional case series. In 54 eyes of 27 myopic subjects FD-OCT iridocorneal angle measurements were made before and 1 month, 3 months, 1 year, and 2 years after ICL implant. Trabecular-iris angle (TIA), angle opening distance 500 μm from the scleral spur (AOD₅₀₀), and iridotrabecular contact length (TICL) were compared among these time points and the nasal, temporal, and inferior quadrants. Preoperative TIAs were 49.5 ± 8.7, 48.3 ± 9.6, and 49.1 ±8.6 degrees for the nasal, temporal and inferior quadrants (P < .001). Corresponding values were 29.9 ± 10.4, 28.4 ± 10.8, and 28.8 ± 9.7 degrees at 1 month and 27.3 ± 8.8, 26.8 ± 8.1, and 28.9 ± 7 degrees at 2 years of follow-up, indicating angle narrowing of 39%-45% and no further narrowing beyond 1 month in the nasal (P = .133), temporal (P = .376), and inferior (P = 1.000) quadrants. Trabecular-iris contact (TIC) was observed in 8 eyes of 8 subjects, mostly only in the temporal quadrant. Mean TICL failed to vary during follow-up (307 ± 288 μm at 3 months and 225 ± 142 μm at 2 years, P = .159). In response to ICL V4c implant, considerable angle narrowing was detected at 1 month but this narrowing remained stable at 2 years. In the 8 cases of TIC, no progression of contact was observed beyond 3 months postimplant.