To evaluate the long-term clinical effect and safety of YK-KC lens® (LucidKorea Ltd., Seoul, Korea) for keratoconus.

In this study we investigated 152 keratoconic eyes fitted with YK-KC lens® and followed up for at least 5 years. We assessed retrospectively self-reported patient comfort, best corrected visual acuity, corneal topographic indices before and after contact lens fitting and complications during contact lens wearing.

The study included 57 male and 40 female patients with a mean age of 28.6 ± 8.5 years. The mean follow-up was 8.0 ± 2.9 years. Regarding lens comfort, 126 eyes (82.9%) showed self-reported comfort for YK-KC lenses®. The mean best corrected visual acuity (log MAR) improved from 0.49 ± 0.42 before lens fitting to 0.19 ± 0.27 after lens wearing, which was statistically significant ( p < 0.001). Based on the keratometric values, after contact lens fitting both Simulated keratometry (Sim K) max and Sim K min tended to be steeper, but these differences were not statistically significant ( p = 0.66 and 0.11, respectively). There were no statistically significant differences between the values before and after fitting with respect to the astigmatic powers ( p = 0.22). Complications observed included punctate or coalesced epithelial corneal staining in 24 eyes (16%), however, persistent full-thickness epithelial defect was not observed.

The YK-KC lens® in patients with keratoconus can provide excellent visual improvement and comfort without any significant influence on the progression of keratoconus or corneal complications during a long-term follow-up period.