Long-term observation of V4c implantable collamer lenses implantation for moderate to extreme high myopia correction: five years follow-up

Background This study aims to assess the long term effectiveness, safety, predictability and stability of V4c implantable collamer lenses (ICL) for correction of moderate to extreme high myopia. Methods We reviewed 125 eyes from 64 patients who implanted V4c ICL at the Refractive Surgery Center of West China Hospital in Chengdu, China, between May 2015 and January 2017. The median spherical equivalent was −11.50 D (interquartile range [IQR]: −13.00 to −9.00 D). We followed up with the patients over five years and evaluated several parameters, including uncorrected visual acuity (UDVA), corrected visual acuity (CDVA), axial length, refractive error, endothelial cell density (ECD), intraocular pressure (IOP), white-to-white distance (WTW), and vault. We performed a correlation analysis to explore the potential impacts on vault following implantation. Results The median safety index (postoperative CDVA/preoperative CDVA) during the last follow-up was 1.00 (interquartile range [IQR]: 1.00–1.20), and the efficacy indices (postoperative UDVA/preoperative CDVA) were 1.20 (IQR: 1.00–1.25), 1.20 (IQR: 1.00–1.33), and 0.8 (IQR: 0.65–1.00) at postoperative 1 week, 1 month, and 5 years, respectively. At the five-year mark, 16% of the eyes were within ±0.50 D of expected correction, and 73% were within ±2.00 D. No significant difference in ECD was observed between pre-operative and post-operative measurements. Compared to baseline, we observed a significant increase in IOP at the one-week follow-up, which decreased significantly at the one-month visit. Furthermore, we identified ICL size and spherical equivalent (SE) as independent variables in a multiple linear regression model that accurately predicted the five-year vault after surgery. Conclusion In conclusion, V4c ICL implantation is an effective and safe treatment for moderate to extreme high myopia with good predictability and stability over the long-term.