Background: Dysfunctional lens index (DLI) changing is rarely reported after implantable collamer lens (ICL) implantation. In the current research, we hope to investigate the changes of DLI by ray-tracing aberrometry before and after implantation of the posterior chamber phakic implantable collamer lens with a central artificial hole for patients with moderate-to-high myopia.
Methods: This retrospective, observational case series included 206 eyes of 104 patients with moderate-to-high myopia who underwent ICL V4c implantation. Data were collected on ocular indicators preoperatively and at 1 day, 1, 3, and 6 months postoperatively. The i-Trace Visual Functional Analyzer was used to assess the DLI measurement.
Results: The overall values of safety index and efficacy index were both more than 1. Preoperatively, the mean spherical equivalent (SE) of included 206 eyes was - 10.77 ± 3.46 diopter (D). Then at 1-day postoperation, the mean SE was - 0.22 ± 0.55 D, and barely changed from 1 day to 6 months postoperatively. Although the endothelial parameters had no significant differences between preoperation and postoperation, the mean loss of endothelial cells was 0.74 ± 0.98% at 6 months. Regarding the vault, there was a significant difference between each time of follow-up (P < 0.001). The mean of the vault decreased 109.6 ± 13.5 µm from 1-day post-op to 6 months post-op. The DLI values were 3.70, 9.26, 10.00, and 9.68 at baseline, 1, 3, and 6 months, respectively (P < 0.001), but no significant differences were found between 1, 3, and 6 months postoperatively (P > 0.05). The preoperative lnDLI showed a significant positive linear correlation (r = 0.621, P < 0.001) with the preoperative spherical equivalent (SE). The lnDLI was negatively correlated with the axial length (r = - 0.462, P < 0.001), corneal thickness (r = - 0.207, P = 0.003), preoperative LogMAR UDVA (r = - 0.189, P = 0.006), and preoperative LogMAR CDVA (r = - 0.306, P < 0.001).
Conclusions: The postoperative refractive parameters were confirmed excellent in efficacy, predictability, and stability in half a year. The DLI was significantly improved after the ICL V4c implantation in patients with moderate-to-high myopia and showed good stability during the follow-up periods. The DLI deserves a more comprehensive understanding and application in clinical services.
Keywords: Dysfunctional lens index; Moderate-to-high myopia; Phakic intraocular lens; Refractive surgery.
© 2023. The Author(s).