Epi-on high-oxygen CXL shows comparable results, less pain than epi-off room-air CXL
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MARRAKECH, Morocco — The preliminary results of a study comparing individualized topography-guided corneal cross-linking with epithelium-on high-oxygen protocol vs. epithelium-off room-air protocol show that the epi-on procedure might be a valid alternative, with comparable results but less pain.
“CXL can be used to treat keratitis but can also cause keratitis, probably because of removal of the epithelium. In addition, the epi-off treatment results in quite severe pain for at least 4 days,” Anders Behndig, MD, PhD, said at the European Society of Cataract and Refractive Surgeons Winter Meeting.
The Customized Remodeled Vision (CuRV) treatment with the Mosaic system (Avedro/Glaukos) has shown refractive advantages over conventional CXL in keratoconus. Treatment is individualized based on corneal topography, delivering higher energy over the cone and lower energy where the cornea is flatter. In an ongoing study using the CuRV approach, 22 keratoconus patients were treated bilaterally with an epi-on high-oxygen protocol, using an oxygen mask in one eye, and a room-air epi-off protocol in the other eye, scraping the epithelium under local anesthesia.
HPMC riboflavin was used for 10 minutes, and UV irradiation was customized based on topography, with a maximum effect in the range of 7.2 J/cm2 to 15 J/cm2, based on the maximum keratometry reading.
“The more severe the keratoconus, the higher the energy delivered,” Behndig said. “Energy is highest over the cone, tapering by 2 J/2 D based on the posterior surface.”
Because patients were treated bilaterally on the same day, it was easy to see that the epi-off eye had more pain for several days, even up to 1 week, while after 3 or 4 days the epi-on eye was pain-free. No difference was found in the depth of the demarcation line. Uncorrected visual acuity, best corrected visual acuity and low-contrast visual acuity improved in both eyes, with no significant difference at 3 months. Endothelial cell count was unchanged with both treatments, and no adverse events were reported.
“These early results indicate that the novel high-oxygen epi-on approach may be a promising alternative to epi-off CuRV. The study is ongoing, and with more patients and a longer follow-up, we will be able to see if these first impressions are confirmed,” Behndig said. – by Michela Cimberle
Reference:
Behndig A, et al. Individualized topography-guided crosslinking for keratoconus: comparison of epi-on/high oxygen to epi-off room air protocols. Presented at: European Society of Cataract and Refractive Surgeons Winter Meeting; Feb. 21-23, 2020; Marrakech, Morocco.
Disclosure: Behndig reports no relevant financial disclosures.
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