Riboflavin Compound Demonstrates Persistent Corneal Thinning Following CXL

Using 20% dextran-based or 1% hydroxypropyl methylcellulose (HPMC)-based riboflavin applications during corneal crosslinking (CXL) both demonstrate efficacy for improving visual outcomes and halting keratoconus (KC) progression in children, according to a study published in the American Journal of Ophthalmology. The HPMC-based application, however, may show long-term corneal thinning in pediatric patients, creating a concern over its use during the CXL procedure.  

Researchers included 58 children with keratoconus (mean age, 13.0 years; 77.6% boys; eyes, 74) who underwent CXL in the prospective, clinical cohort study conducted at a single center. The team stratified eyes according to the riboflavin application used during the procedure (dextran, n=21; HPMC, n=53). Study participants underwent visual acuity,  anterior segment optical coherence tomography (OCT), corneal tomography, and specular microscopy assessments at baseline, 3 and 6 months, and 1,2,3,4,5 and 7 years postsurgically.

Corrected and uncorrected distance acuity improved at all follow-up visits for both groups, with statistically significant improvements in corrected visual acuity observed at 1, 2 and 3 years. Maximum keratometry flattened throughout the 7-year follow-up period. Patients who underwent dextran-based riboflavin application experienced significant mean thinnest pachymetry decreases  at 3 months, but these values recovered to baseline measurements at the 6-month follow-up visit. Thinnest pachymetry values among individuals treated with the HPMC application, however, remained significantly thinner than baseline values throughout the study duration, the report shows. 

“An individual CXL treatment, personalizing the energy, time of treatment and even the type of riboflavin, should be conducted in accordance with KC severity (corneal curvature and thickness), preventing the most apical and/or thinnest area of the cone from receiving stronger treatment,” according to researchers. “Attention to the type of protocol used, the formulation of the riboflavin and soaking time play an important part [in] the final result and safety of CXL.”

Study limitations include a single center design.