Figure 4: Accelerated corneal collagen crosslinking Group 2 (epitheliumoff): Riboflavin 0.1% plus Dextran 20%, 20 min of corneal soaking, UV-A power at 30 mW/cm2, Energy dose at 7.2 J/cm2), 4 min exposure time. Postoperative confocal scans revealed lacunar edema (upper left white arro -a) with keratocytes apoptosis (upper right white arrow-b) and increased density of extracellular matrix (bottom left white arrow-c). A transition between hypo-cellular stroma and stroma unreached by the treatment (vertical transition area) is showed in bottom left - d scan with an estimated penetration depth of 160 μm (range 150-180 μm).