Iridocorneal angle changes after implantable collamer lens (ICL) implantation: A 10-year follow-up study

To evaluate changes over a 10-year period in the iridocorneal angle following implantable collamer lens (ICL) implantation.

This retrospective study included 48 eyes of 24 patients who underwent ICL implantation. Trabecular-iris angle (TIA₅₀₀), trabecular-iris space area (TISA₅₀₀), and angle opening distance (AOD₅₀₀) at 500μm from the scleral spur, along with vault distance, were measured using Fourier-domain anterior segment optical coherence tomography (AS-OCT). Primary endpoints were changes in TIA₅₀₀, TISA₅₀₀, and AOD₅₀₀ from baseline to year 10. Secondary outcomes included changes in vault and predictors of anterior chamber angle opening.

Forty-eight eyes of 24 patients were included in the study. The mean spherical equivalent was -9.1±3.9 diopters, with 60.4% of eyes receiving a spherical ICL and 39.6% a toric ICL. Significant reductions in nasal and temporal TIA₅₀₀ (P<0.001) were observed at month 1, stabilizing over 10 years. Similar patterns were found for TISA₅₀₀ and AOD₅₀₀. The vault demonstrated a gradual decrease over time. Multiple regression analysis revealed that preoperative TIA₅₀₀ and postoperative vault at 1 month were significantly associated with TIA₅₀₀ at both 1 month (P<0.0001, P=0.0050, P=0.0080, and P=0.0191, respectively) and 10 years postoperatively (P=0.0011, P=0.0016, P=0.0128, and P=0.0293, respectively) in the nasal and temporal quadrants.

ICL implantation provides long-term stability in the iridocorneal angle opening, with preoperative angle measurements serving as key predictors of long-term outcomes. This stability was maintained even after a decade, highlighting the procedure's durability in terms of anterior segment configuration.