Long-Term Angle Changes After Posterior Chamber Phakic Intraocular Lens Implantation Under Differing Lighting Conditions

To investigate the long-term iris-trabecular contact (ITC) after implantable collamer lens (ICL) V4c implantation and the anterior chamber angle (ACA) changes under differing lighting conditions.

Eye and ENT Hospital, Fudan University

Noninterventional, cross-sectional observational study. 17 women and 10 men, 54 eyes were included seven years after undergoing ICL V4c implantation. Pupil size, postoperative vault, and angle were evaluated using a swept-source optical coherence tomography system under photopic and mesopic conditions sevenyears postoperatively.

At seven years postoperatively, ITC was observed after ICL implantation in seveneyes of five subjects (13.0%), with a shallower anterior chamber depth (ACD) and smaller anterior chamber volume (ACV). The mean ITC index and areas for these eyes were 27.71±20.06 degrees (range, 13 to 68 degrees) and 0.50±0.50 mm² (range, 0.075 to 1.356 mm²), respectively, mostly in the nasal quadrant. Under photopic conditions, the average TIA₅₀₀, AOD₅₀₀, and TISA₅₀₀ values significantly increased, whereas the vault and pupil size significantly decreased. In addition, the anterior chamber angle (ACA) was narrowest in the superior-nasal quadrant and widest in the inferior-temporal quadrant.

A change under photopic conditions in both the vault and angle during long-term follow-up and the angle narrowing and ITC in the nasal quadrant are worth our attention, especially for the patients with shallower ACD and smaller ACV.