Assessing Effects of Riboflavin/UV-A Cross-Linking on Aqueous Outflow Facility, Corneal Biomechanics and Their Association With Intraocular Pressure

Riboflavin/UV-A corneal collagen cross-linking (CXL) is a standard treatment for early-stage keratoconus. However, quantitative CXL outcomes remain limited. This study evaluated CXL effects on outflow facility and corneal biomechanics at intraocular pressures (IOPs) in ex vivo porcine eyes. Ocular rigidity and outflow facility were derived from pressure–volume and IOP decay curves using a direct manometric technique, while corneal elasticity (Young's modulus) was measured via non-contact air-pulse optical coherence elastography. CXL increased ocular rigidity (0.0066 ± 0.0001 μL−1 vs. 0.0060 ± 0.0002 μL−1) and reduced outflow facility from 0.5429 ± 0.0320 to 0.1485 ± 0.0153 μL/min/mmHg (20–40 mmHg), compared to 0.7327 ± 0.0894–0.2210 ± 0.0502 μL/min/mmHg in untreated eyes. Young's modulus increased by 92%, 89%, and 155% at 20, 30, and 40 mmHg. These findings enhance our understanding of flow dynamics at IOP levels, suggesting that outflow facility and corneal biomechanics may serve as potential indicators for evaluating the effectiveness of CXL.