Additional file 1: of Effect of the retention ring-assisted continuous application of riboflavin in pulsed-light accelerated corneal collagen cross-linking on the progression of keratoconus KimChung Young Kum KimMee 2019 Supplementary Figure S1. Riboflavin is contained inside a retention ring during the application for 10 minutes (A). A trephined silicone hydrogel bandage contact lens is applied during UV irradiation (B, C) (TIF 9431 kb)