Tomographic indices as possible risk factors for progression in pediatric keratoconus

Abstract

Purpose: To determine whether corneal tomography can help predict the risk of progression of keratoconus in children.

Methods: The medical records of pediatric patients with keratoconus presenting to a large tertiary institution in the UK from 2009 to 2014 were reviewed retrospectively. Patients underwent serial clinical examination and corneal tomography. The minimum follow-up period was 5 months. Patients with a history of eye surgery including corneal crosslinking were excluded. The following tomographic parameters were analyzed: thinnest corneal thickness (TCT), average central corneal keratometry (Km), and maximum central posterior elevation (MCPE). The rate of progressive corneal thinning, in μm/month, was calculated as the difference between TCT on presentation and at the most recent visit divided by the time in months.

Results: A total of 36 eyes of 19 patients (10-16 years of age) were included. Mean follow-up was 19 months (range, 5-30 months). Six eyes (17%) developed corneal scarring and 1 eye (3%) developed acute hydrops. Of the 29 eyes that did not develop corneal scarring or hydrops, 24 (83%) demonstrated progressive corneal thinning over the period of the study. Eyes with TCT of <450 μm, Km above 50 D, and MCPE above 50 μm at presentation demonstrated the highest rates of progressive corneal thinning over the study period.

Conclusions: In pediatric keratoconus, lower TCT, higher Km, and higher MCPE on corneal tomography seem to be risk factors for faster rates of progressive corneal thinning.