Título

Accelerated Corneal collagen cross-linking with special formulation of riboflavin for keratoconus in young patients.

Introdução

The purpose of this study is to evaluate the outcome of accelerated epi-off corneal collagen cross-linking (CXL) in eyes with progressive keratoconus (KCN) at Bonsucesso Federal Hospital, using hypoosmolar riboflavin with hydroxypropyl methylcellulose.

Método

A retrospective study in which a total of 20 eyes with progressive KCN and age < 21 years old were enrolled. All patients underwent accelerated CXL using hypoosmolar (200 mOsm) riboflavin with hydroxypropyl methylcellulose and continuous ultraviolet-A (UVA) light exposure at 9 mW/cm for 10 minutes; total energy dose was 5.4 J/cm. Pre- and post-operative examinations included, central corneal thickness (CT) and corneal topographic evaluation (flat, steep meridian keratometry (K) and maximum keratometry). Progression was defined as an increase of more than 1 diopter (D) in Kmax. Statistical analysis was performed using a 2-tailed paired sample Student t test.

Resultados

Mean age at time of CXL was 16.8 ±4.0 years (range, 9 - 21 years). Mean follow-up was 10 ± 4 months (range, 6 – 19 months). Mean preoperative CCT was 463.8±43.6 µm (range 394 to 566 µm) and mean postoperative CCT was 444.9 ±42.2 µm, p= 0.01). Mean pre-operative K max was 60.2 ± 8.0 D. Mean post-operative K max at the last follow-up was 60.21 ± 7.9 D. No intra- or postoperative complications were observed. There was no significant difference between of all topographic indices (steep K, flat K, Kmax, and topographic cylinder) considering the last follow-up visit compared to preoperative topographic indices (p> 0.05). Progression was observed in 5 (25%) patients. Flattening of the Kmax was observed in 8 patients, ranging from -0.3 to - 6.0D.

Conclusões

Successful stability was obtained in only 75% of the cases. This can be explained by the fact that the majority were advanced cases and by the young age, since in both situations the successful rate is expected to be lower.