Progression of keratoconus in children and adolescents

Aims To evaluate the rates of keratoconus progression and associated factors in eyes of children and adolescents. Methods Retrospective, cohort study of individuals <= 18 years old at the time of keratoconus diagnosis and with at least 6 months of follow-up. Corneal tomography was performed using an Orbscan tomographer (Bausch & Lomb, Rochester, New York, USA) to determine whether progression occurred. Tomographic progression of keratoconus was defined as a change in any of the investigated parameters (keratometry values, K-MAX, maximum anterior or posterior elevation, central pachymetry, thinnest pachymetry) beyond the limits of repeatability. Results 148 eyes of 106 patients with a mean age of 15.2 +/- 2.5 years were studied over a mean follow-up period of 2.9 +/- 2.2 years. The overall rate of tomographic progression was 77.0% (114/148 eyes). Eyes that progressed had more advanced disease at presentation with higher anterior curvature (K(MAX)55.4 +/- 6.3 vs 52.2 +/- 5.4 dioptres; p<0.01), posterior elevation (108.2 +/- 40.9 vs 86.3 +/- 35.6 mu m; p<0.01) and lower central pachymetry measurements (442.1 +/- 56.7 vs 454.4 +/- 47.5 mu m; p=0.01). Age at presentation, gender, atopy, documented eye rubbing, ethnicity and duration of follow-up were not significantly associated with progression in the multivariate analyses. There was a higher rate of bilateral progression if at least one eye had severe keratoconus (73.9%) compared with no severe keratoconus in either eye (36.8%; p=0.03). Conclusions A high rate of progression was identified in keratoconic eyes of children and adolescents. More advanced disease at initial presentation may increase the risk of further keratoconus progression.