Outcomes of iontophoretic corneal collagen crosslinking in keratoconic eyes with very thin corneas

The purpose of this retrospective study was to report the results of iontophoretic corneal collagen crosslinking (I-CXL) with riboflavin and ultraviolet A irradiation in patients affected by keratoconus, each with thinnest pachymetry values of <400 μ (with epithelium) and not treatable using standard epithelium-off technique.Fifteen eyes of 15 patients affected by progressive keratoconus and with thinnest pachymetry values <400 μ underwent I-CXL. The uncorrected (UDVA) and corrected (CDVA) distance visual acuity, maximum and minimum keratometry (K max and K min) readings, corneal thickness at the thinnest point (CTTP), endothelial cell density (ECD), and intraocular pressure (IOP) were assessed before I-CXL, at 1, 3, 6, and 12 months postoperatively.The mean UDVA and CDVA significantly increased 12 months after I-CXL (P = .002 for both comparisons). The K max readings significantly decreased at 6 and 12 months postoperatively (P = .04 and P = .02, respectively). The mean CTTP improved at the end of the follow-up (P = .008). ECD was unchanged. No side effects or damage to the limbal region was observed during the follow-up period.I-CXL has been proved to be effective in halting keratoconus progression in eyes with very thin corneas, with no side effects during the follow-up period. This procedure could be used in patients with more advanced keratoconus.