Use of hypo‐osmolar riboflavin for corneal cross‐linking in thin keratoconic corneas

Abstract Purpose To evaluate the efficacy of UVA collagen cross linking (CXL) on thin keratoconic corneas with previous application of hypoosmolar riboflavin solution. Methods Twelve eyes of 12 patients with progressive keratoconus and a corneal thickness of less than 400 µm without the epithelium, were submitted to collagen cross‐linking after the application of an hypoosmolar riboflavin solution. We instilled one drop every 5 seconds for 2 or 4 minutes to increase corneal thickness up to a minimum value of 400 µm. Pachimetry measurements were taken every 30 seconds to verify the effect on corneal stroma. Results Mean corneal thickness improved in most cases with reduction of the mean K‐value of the keratoconus and no progression was observed at six and twelve months after CXL. One year after treatment no scarring lesions in the stroma were observed and all corneas were transparent. Improvement of visual acuity was significant in three patients (25%), low but detectable in seven patients (51%) and no modifications of visual acuity were observed in two patients (24%). Conclusion Hypoosmolar riboflavin solution showed to be useful to allow CXL procedure in keratoconic corneas with low stromal thickness. No progression of keratoconus was observed six months and one year afer CXL., no developing of stromal scars and patients showed good stability of visual acuity delaying time of surgery.