Tomographic indices as possible risk factors for progression in pediatric keratoconus

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

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.

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.

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.