Keratoconus In Children: Topographic Features By A Scheimpflug-Based Corneal Topography

To identify the main topographic and clinical findings in pediatric patients with keratoconus (KC) as well as the KC phenotypes, and to determine the severity at diagnosis according to the Amsler-Krumeich scale and the Belin ABCD severity scale.

Asociación Para Evitar la Ceguera en México, Mexico City, Mexico.

February 2012 to Mach 2019

Retrospective case series studies that collected clinical and topographic data from pediatric patients with newly diagnosis of KC at a tertiary eye hospital in Mexico City, Mexico, between February 2012 and Mach 2019. Patients were clinically and topographically evaluated, collecting their uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), clinical signs, corneal topography, and pachymetry data.

400 eyes of 204 patients included. Median age of 13 years old (SD±4, 4- 17), 62.25% (n= 127) were male. Clinical signs of KC were found in 282 (69.1%), prominent corneal nerves (31.6%) and corneal thinning 25.7% were the most common. Median UCVA at diagnosis was of 0.7 LogMAR (IQR 1.27-0.4). Median BCVA was of 0.2 LogMAR (IQR 0.4-0.1). At admission nearly 50% of the eyes were at stage 4 of the severity scale in Amsler-Krumeich classification. Ther was a positive linear correlation, between high order aberrations and KC (p<0.0001) and the more severe the KC, the higher HOAs values were observed (p<0.0001). In regards to KC phenotype the most frequent one was the Snowman 1 type (39.16%) followed by the Duck type (24.10%).

Nearly half the population of our study had a more severe grade of keratoconus in the AKS in comparison with other populations. The ABCD severity scale results in our study seems to confirm an earlier corneal curvature disturbance before the corneal thinning and visual impairment, showing the ABCD severity scale could also be used as a screening tool in pediatric population since it allows us to beware of early changes. A directly proportional relationship was found between the degree of severity of KC and higher order corneal aberrations (HOAs). To the best of our knowledge this is the first study to use the ABCD severity scale for KC in children, as well to describe the keratoconus phenotypes and HOAs in this population.