Corneal Collagen Crosslinking for Keratoconus Patients

PICHON RIVIERE, A.; AUGUSTOVSKI, F.; GARCIA MARTI, S.; GLUJOVSKY, D.; ALCARAZ, A.; LOPEZ, A; BARDACH, A.; CIAPPONI, A; ROMANO, M

Documento de Evaluación de Tecnologías Sanitarias

IECS

Año: 2013 p. 1 - 30

1668-2793

Keratoconus is a disorder that causes the thinning and ectasia (frontal protrusion) of the corneal surface, consequently decreasing visual acuity (VA). It is generally bilateral and progressive. Its etiology is not defined and it usually affects children and young people. In the general population, the reported frequency is 1 every 2,000 people. As treatment, hard contact lenses are used for mild cases. Keratoplasty (corneal transplant) may be used for advanced cases. Intrastromal ring implantation (Intacts®) and cross-linking (CXL) are proposed as treatment for moderate keratoconus, isolated or to supplement other treatments. Technology ?Cross-linking? (CXL) involves applying a photosensitive product in the cornea, such as riboflavin and then activating it using ultraviolet light-A (UVA) in order to harden the cornea by creating bridges between the collagen fibrils through phototherapy biochemical action, thus stopping keratoconus progression. The procedure is performed in an ambulatory setting under topical anesthesia. The corneal epithelium is eroded in order to facilitate riboflavin penetration. Riboflavin drops are placed while the eye is radiated with UVA for about 30 minutes. Purpose To assess the available evidence on the efficacy, safety and coverage related aspects regarding corneal collagen crosslinking use in patients with keratoconus. Methods A bibliographic search was carried out on the main databases: DARE, NHS EED, on Internet general search engines, in health technology evaluation agencies and health sponsors. Priority was given to the inclusion of systematic reviews; controlled, randomized clinical trials (RCTs); health technology assessments and economic evaluations; clinical practice guidelines and coverage policies of other health systems. Results Three controlled randomized clinical trials (RCTs), two Clinical Practice Guidelines (CPGs), three Health Technology Assessments (HTAs) and two coverage policies were found. In one RCT published in 2011 which included 71 eyes, each eye was randomized to CXL treatment or riboflavin alone (placebo). The study does not report comparisons between the treated and untreated groups. In the CXL group, corrected and uncorrected VA improved significantly at 12 months (from 20/137 to 20/117 and from 20/45 to 20/34 respectively, this is the same as improving one line in the Snellen VA Chart) compared with the patient?s baseline. In the treated group there were also statistically significant improvements in the ketarometry readings. In the control group (no treatment), no significant differences were observed in VA at 12-month-follow up. CXL was effective in improving the VA with and without correction. Another prospective randomized study published in 2011 enrolled 24 patients with mild to moderate keratoconus with recent progression. One of the patient?s eyes was randomized to CXL and the other to control. Follow up was 18 months in 22 patients. In the treated group, the corrected VA at 18 months improved (p=0.01), as well as the keratometry readings by simulated Orbscan II (p