Orthokeratology and riboflavin-UVA corneal collagen cross-linking in Keratoconus

• Autores: Antonio Calossi, Ferdinando Romano, Giuseppe Ferraioli, Vito Romano
• Localización: Journal of Emmetropia: Journal of Cataract, Refractive and Corneal Surgery, ISSN-e 2171-4703, Vol. 1, Nº. 3, 2010, págs. 126-131
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • PURPOSE: A prospective study was designed to answer two questions: Is it possible to improve the quality of vision of keratoconus patients with overnight orthokeratology? Is it possible to stabilize the effect of corneal reshaping through collagen cross-linking? METHOD: We developed a molding reverse geometry contact lens, specifically designed to be fitted in keratoconus. The lens was in siloxy-fluoro-methacrylate Dk 100 gas-permeable material (Boston XO, hexafocon-A). We selected a group of 5 eyes from 4 patients (3 females, 1 male) aged 22 to 43 years with clinical and topographical diagnosis of keratoconu.

    All patients were suffering from visual symptoms, intolerant to conventional CL, with corneal pachimetry > 400 µm. Patients underwent overnight orthokeratology (OK) for three months, then collagen cross-linking (CXL) was performed with riboflavin + UVA following the Siena group protocol. After a one-month gap for healing process, overnight orthokeratology was resumed with piggy-back (RGP + silicone-hydrogel CL) for three weeks, and with RGP lenses only for two further months. All kinds of CL were discontinued thereafter.

    RESULTS: Data were collected at base line, at three months after OK, at four months after cross-linking (one month after OK interruption), and at one year after cross-linking. In all cases, corneal topography showed an improvement in corneal shape after overnight orthokeratology, with a significant reduction of corneal aberration. One month after OK interruption, corneal topography and corneal wave-front error returned at baseline level and remained stable at one-year follow-up. Uncorrected visual acuity (UCVA) and best spectacle corrected visual acuity (BSCVA) improved after orthokeratology; this improvement was reduced one month after OK lens interruption (4 months post CXL), but did not return to baseline level.

    No adverse reactions were observed during the three months of OK. After cross-linking, one eye showed an epithelial defect with asymptomatic iritis-like reaction. This complication resolved after a month of topical steroid therapy, so the treatment was continued. No relevant adverse events were observed at 4 months and one year after cross-linking.

    CONCLUSION: Overnight orthokeratology may reshape the keratoconic cornea without significant adverse reactions. Riboflavin-UVA corneal collagen cross-linking is quite safe, but it is not able to stabilize the OK molding effect. Nevertheless, UCVA and BSCVA improved as compared to baseline level. At present, we are not able to explain this discrepancy.