Use of hypo-osmolar ribofl avin for corneal cross-linking in thinkeratoconic corneas

Purpose To evaluate the effi cacy of UVA collagen cross linking (CXL) on thin keratoconic corneas with previous application of hypoosmolar ribofl avin 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 crosslinking after the application of an hypoosmolar ribofl avin 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 eff ect on corneal stroma. Results Mean corneal thickness improved in most cases with reduction of the mean K-value of the keratoconus and no progressionwas 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 signifi cant in three patients (25%), low but detectable in seven patients (51%) and no modifi cations of visual acuity were observed in two patients (24%). Conclusion Hypoosmolar ribofl avin solution showed to be useful to allow CXL procedure in keratoconic corneas with low stromalthickness. 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.