Customized Topography-Guided Crosslinking In Keratoconus - Comparison Of Epi-On High/Oxygen To Epi-Off/Room Air Protocols

To compare the efficacy, safety and healing phase of two different crosslinking (CXL) protocols for keratoconus.

University hospital eye clinic.

This ongoing single-masked, intra-individually comparing study so far includes 47 patients with bilateral progressive keratoconus treated with bilateral CXL; one eye with a high-oxygen epi-on protocol, the other eye with an epi-off protocol in room air, which was randomized. Uncorrected (UDVA) and corrected visual acuities (CDVA), low- contrast visual acuities, refractive spherical equivalents (SE), endothelial cell count (ECC) and adverse events were analyzed before treatment and through 60-month follow-up. The discomfort symptoms during the healing phase for each eye was registered using a visual analogue scale during the first week post-treatment. So far 31 patients have completed their 12-month visit.

UDVA improved at 12 months (-0.19 ±0.23 logMAR for epi-on; -0.18 ± 0.19 logMAR for epi- off, p<0.05), as did the CDVA (-0.11 ± 0.12, -0.11 ± 0.14, respectively, p <0.01), the Kmax (- 1.55 ± 1.27, - 1.60 ± 1.33 D, respectively, p <0.01), LCVA 10% (-0.18 ± 0.19, -0.15 ± 0.14, respectively, p<0.01) and LCVA 2.5 % (-0.36 ± 0.84, -0.30 ± 0.65, respectively, p <0.05). The epi-on eyes had less discomfort during the first week post-treatment. ECC was unchanged with both protocols at 12 months. No adverse events occurred. 

Our 12-months results indicate that the novel individualized high-oxygen epi-on treatment protocol can be a promising alternative to an epi-off protocol. Our 24-months results are approaching.