Purpose: To assess ultrastructural stromal modifications after riboflavin-UVA-induced cross-linking of corneal collagen in patients with progressive keratoconus.
Methods: This was a second-phase prospective nonrandomized open study in 10 patients with progressive keratoconus treated by riboflavin-UVA-induced cross-linking of corneal collagen and assessed by means of Heidelberg Retinal Tomograph II Rostock Corneal Module (HRT II-RCM) in vivo confocal microscopy. The eye in the worst clinical condition was treated for each patient. Treatment under topical anesthesia included corneal deepithelization (9-mm diameter) and instillation of 0.1% riboflavin phosphate-20% dextran T 500 solution at 5 minutes before UVA irradiation and every 5 minutes for a total of 30 minutes. UVA irradiation was 7 mm in diameter. Patients were assessed by HRT II-RCM confocal microscopy in vivo at 1, 3, and 6 months after treatment.
Results: Rarefaction of keratocytes in the anterior and intermediate stroma, associated with stromal edema, was observed immediately after treatment. The observation at 3 months after the operation detected keratocyte repopulation in the central treated area, whereas the edema had disappeared. Cell density increased progressively over the postoperative period. At ∼6 months, keratocyte repopulation was complete, accompanied by increased density of stromal fibers. No endothelial damage was observed at any time.
Conclusions: Reduction in anterior and intermediate stromal keratocytes followed by gradual repopulation has been confirmed directly in vivo in humans by HRT II-RCM confocal microscopy after riboflavin-UVA-induced corneal collagen cross-linking.
From the *Department of Ophthalmology and Neurosurgery, University of Siena, Siena, Italy; and the †Ophthalmology Institute, Catholic University, Rome, Italy.
Received for publication June 5, 2006; revision received November 8, 2006; accepted November 21, 2006.
The authors state that they have no proprietary interest in the products named in this article.
Reprints: Angelo Balestrazzi, Dipartimento di Scienze Oftalmologiche e Neurochirurgiche, Università di Siena, Viale Bracci 1, 53100 Siena, Italy (e-mail: firstname.lastname@example.org).