One-Year Longitudinal Assessment of Subjective and Objective Accommodation After Phakic IOL Implantation

Purpose: To evaluate the 1-year behavior of accommodation and optical quality one year after the implantation of phakic intraocular lenses, specifically the implantable collamer lens (ICL), in myopic patients, comparing outcomes between low- and high-myopia groups. Methods: This comparative longitudinal study included 38 eyes of 38 patients who underwent ICL implantation for myopia correction. Patients were divided into two groups based on preoperative manifest sphere: low myopia (−2.50 D to −6.25 D) and high myopia (>−6.25 D to −12.50 D). The amplitude of accommodation (AA), subjective accommodative response (AR), optical quality parameters including the modulation transfer function (MTF) cut-off, objective scatter index (OSI) and Strehl ratio (SR), and objective accommodative response with a double-pass system (HD Analyzer, Visiometrics) were assessed preoperatively, 1 month, and 1 year postoperatively. Results: Both groups achieved postoperative refractive outcomes close to emmetropia, with high efficacy and safety indices. A statistically significant decrease in the amplitude of accommodation was observed at 1 month and remained stable at 1 year in both groups; however, this change was not clinically meaningful. The optical quality parameters (MTF cut-off, OSI, and Strehl ratio) and objective accommodative response with the HD Analyzer showed no clinically relevant changes over time, with no significant intergroup differences detected (p-value > 0.05). Conclusions: An initial reduction in accommodative amplitude was observed after ICL implantation without recovery over time; however, it was not clinically relevant, as it fell within the test–retest variability in the minus lens technique. Other accommodative parameters and optical quality remained stable at 1 year in both low and high myopia.