Abstract
Background: KeraVio, a portable corneal cross-linking (CXL) treatment modality involving the use of violet light (VL)-emitting glasses, was originally used in conjunction with topical transepithelial riboflavin (BJO 2021). However, after our preliminary findings of endogenous riboflavin in the human cornea and the observation that the relatively low intensity of VL irradiation increased corneal stiffness in porcine corneas (TVST 2021), we evaluated the clinical results of KeraVio without riboflavin drops. Methods: Patients with progressive keratoconus were enrolled and randomly divided into a VL irradiation alone group (Group 1) and a no irradiation group (Group 2; control group) (jRCTs032190267). The eyes were exposed to VL (375 nm, irradiance 310 μW/cm(2))-emitting glasses for 4.5 h daily for 6 months. Results: The mean changes in the maximum keratometry value (Kmax) from baseline to 6 months were 0.94 ± 2.65 diopters (D) and 1.76 ± 2.75 D in Group 1 and Group 2, respectively (p = 0.705). Conclusions: No differences were found between patients who did and did not receive VL irradiation in terms of the clinical outcomes of keratoconus. VL irradiation alone likely did not halt keratoconic progression, and the administration of riboflavin was necessary.