This retrospective, observational case series was conducted at Yonsei University College of Medicine, Seoul, Republic of Korea. The tenets of the Declaration of Helsinki and good clinical practice were followed, and institutional review board approval from Yonsei University College of Medicine was obtained (No. 4–2020-0396). Owing to the retrospective nature of the study, the requirement for informed consent was waived. All surgeries were performed by a single surgeon (JHK) between June 2020 and August 2020.
A total of 17 patients with residual myopia or myopic astigmatism after a previous history of LVC were enrolled. All patients decided to have ICL implantation after detailed explanation of possible enhancement options before the surgery. Other inclusion criteria were a stable refractive status for at least 1 year, a preoperative corrected distance visual acuity (CDVA) of 20/30 or better, and no sign of corneal ectasia on at least three consecutive corneal tomographic evaluations. Patients with any kind of ocular surface diseases, ocular trauma, glaucoma, cataract, an endothelial cell density < 2000 cells/mm2, or an anterior chamber depth from the endothelium < 2.8 mm were excluded.
To evaluate outcomes, all patients were assessed before and 3 months after ICL implantation. Patients’ assessments included uncorrected distance visual acuity (UCVA) and CDVA measured in logMAR, slit-lamp examination (Haag-Streit AG), keratometry, pachymetry (ARK-530A Auto Ref/Keratometer, Nidek Co., Ltd.), specular microscopy (SP-3000P, Topcon Corporation), Scheimpflug-based corneal tomography (Pentacam HR, OCULUS Optikgeräte GmbH), and anterior segment optical coherence tomography (Visante, Carl Zeiss Meditec AG). The efficacy index (the ratio of postoperative UDVA to preoperative CDVA) and safety index (the ratio of postoperative CDVA to preoperative CDVA) were also estimated.
All procedures were performed through a superior 3.0-mm corneal incision after instillation of 0.5% phenylephrine and 0.5% tropicamide (Mydrin-P, Santen Pharmaceutical Co., Ltd.) under topical anesthesia with 0.5% proparacaine (Alcaine, Alcon). Further, 1% sodium hyaluronate (Healon, Johnson & Johnson Vision) was injected into the anterior chamber, and the ICL was inserted through an injector cartridge. After positioning the ICL, the sodium hyaluronate was completely removed by manual irrigation and aspiration. The V4c ICL model (Staar Surgical) was used in all cases. ICL powers were calculated using a modified vertex formula provided by the manufacturer. Patients were instructed to use 0.5% moxifloxacin (Vigamox, Alcon) and 1% prednisolone (Pred Forte, Allergan, Inc.) four times a day for a week.
Data are presented as mean ± standard deviation. IBM SPSS Statistics for Windows (v. 25.0, IBM Corporation) was used to perform statistical analyses. Data normality was confirmed using a Kolmogorov–Smirnov test. Pre- and postoperative measurements were compared using a paired t-test for normally distributed data and the Wilcoxon signed-rank test for non-normally distributed data. Comparisons between the two groups were performed using an independent sample t-test for normally distributed data and a Mann–Whitney U test for non-normally distributed data. The refractive predictability was analyzed using linear regression, and comparison of categorical variables was performed using a chi-squared test. A P-value < .05 was considered statistically significant.