Anterior Segment Structure Changes Caused By Different Luminance Light After Implantable Phakic Contact Lens Surgery

To investigate the changes of anterior eye segment with implantable phakic contact lens (ICL) under mesopic and photopic conditions.

The research was carried out by the department of refractive surgery in Shanghai Aier Eye Hospital.

47 eyes of myopic patients who underwent ICL V4c implantation were included. 3 months after surgery, the pupil diameter (PD), vault, ACD (distance from the posterior corneal surface to the anterior lens surface), ACD-ICL (distance from the posterior corneal surface to the anterior ICL surface), and anterior chamber angle parameters were measured using the anterior segment optical coherence tomography (AS-OCT, Carl Zeiss AG, Germany) under completely mesopic (0 lx) and photopic (5290 lx) lighting conditions.

Compared with mesopic conditions, a significant decreased vault was detected in photopic conditions (486.7±186.1um versus 643.5±191.2um, p < 0.001), while the ACD-ICL increased significantly (2.54±0.24mm versus 2.37±0.23mm, p < 0.001). The pupil was smaller in photopic condition (2.66±0.23mm versus 5.62±0.55mm, p < 0.001). ACD didn’t change(3.32±0.24mm versus 3.31±0.22mm, p = 0.079). The change of the vault was positively related to the changes of the PD (r² = 0.301, p = 0.04). There were no statistical difference between the change of vault and the change of ACD-ICL (158.0±58.1um versus 165.9±65.3 um, p = 0.320).

When exposed to high intensity light after ICL surgery, the pupil constricted, vault decreased, ACA widened and ACD-ICL increased. All these changes were caused by the change of iris not the crystalline lens.