Evaluation of biometric indicators of anterior segment parameters after ICL implantation by swept-source optical coherence tomography

Abstract

Purpose. To evaluate the anterior segment structure alteration after implantable collamer lens (ICL) implantation in myopic patients using swept-source quantitative optical coherence tomography (SS-OCT). Methods. This prospective study included 47 eyes of 24 patients with preoperative spherical equivalent ≥ -3.00 D. Patients underwent ICL implantation at Department of Ophthalmology, Peking University Third Hospital, from May 2021 to December 2022. SS-OCT was used to measure biometry including anterior chamber width (ACW), angle opening distance (AOD), angle recess area (ARA), trabecular iris area (TISA), trabecular-iris angle (TIA), iridotrabecular contact (ITC) area and ITC Index before ICL implantation surgery and at 1 month follow-up. Results. At one month following ICL implantation, the ITC area is 0.396 ± 0.37 mm2, and the ITC index is 8.143 ± 5.439 %. All angle parameters, with the exception of ACW, showed a statistically significant reduction on SS-OCT (P<0.05). Mean AOD500, AOD750, ARA500, ARA750, TISA500, TISA750, TIA500 and TIA750 values at one month postoperatively declined by 60.0%, 60.4%, 58.1%, 59.2%, 57.3%, 58.7%, 48.8% and 50.7%, respectively. Vault was positively correlated with ITC index and the percent change in anterior chamber parameters. The vault of >0.659mm was found to be optimal for angle-closure suspect with a sensitivity of 85.2% and a specificity of 53.9%. Conclusions. Anterior chamber parameters decreased 1 month after ICL implantation, and their percentage changes and ITC index correlated with the vault. When the vault is larger than 0.659mm, it is necessary to be alert to possible closed angle suspicion.

A comparative study of two phakic posterior chamber implantable lenses

“…This was the first study to compare ACA500 and AOD500 after phakic IOL implantation, which has been exclusively addressed in existing literature on glaucoma. [23,31] In our study, we observed a significant decrease in the ACA and AOD parameters at 12 months after surgery compared to before the operation. There were no significant differences in the ACA and AOD values observed between ICL and IPCL implantation.…”

“…[23,30] The AOD500 is the distance from the posterior cornea surface and the anterior iris surface, which is measured on a line perpendicular to the trabecular meshwork 500 μm from the scleral spur. [23,30,31] The measures of ACA500 and AOD500 are shown in Figure 1.…”