PARIS — The corneas of patients with Down syndrome present many features similar to those of mild keratoconus eyes, although they do not meet the criteria to be classified as keratoconus, as demonstrated in a study presented at EuCornea 2019.
The study, conducted at the Vissum Institute in Alicante, Spain, included 37 eyes of patients with Down syndrome, 46 eyes with mild keratoconus and 40 healthy control eyes. Corneal topography, tomography, aberrometry, pachymetry and volume analysis were performed using the Sirius system (CSO), a combined Placido disc topographer and anterior segment OCT.
“Comparing topographies of the three groups, you can see similarities between DS and keratoconus patients. Mean posterior keratometry was significantly different between DS and controls but not between DS and mild keratoconus eyes. Keratoconus indexes, specifically posterior surface indexes, showed significant differences between the groups but were higher in both the DS and mild keratoconus group. DS patients and patients with mild keratoconus cases had higher values. Corneal pachymetry showed significantly thinner than normal corneas in both the DS and the mild keratoconus group. Finally, posterior corneal surface aberrometry showed that DS and mild keratoconus eyes had more aberrated posterior corneal surface. [Root mean square], [higher-order aberrations], coma, spherical aberration, coma-like and spherical-like aberrations were similar between DS and mild keratoconus eyes,” Ibrahim Toprak, MD, said.
Despite these similarities, the criteria for classifying Down syndrome patients’ corneas as keratoconus corneas were not met.
“We think that these cases have a specific form of keratopathy, not fully meeting the criteria of keratoconus,” Toprak said.
“Nor of forme fruste keratoconus because these corneas are systematically thinner,” Jorge Alió del Barrio, MD, PhD, who was also involved in the study, said during the discussion. “We could speak of a Down keratopathy, a new concept of DS keratoconus.”– by Michela Cimberle
Toprak I, et al. Characteristics of the posterior corneal surface in Down syndrome patients. Presented at: EuCornea; Sept. 13-14, 2019; Paris.
Disclosures: Toprak and Alió del Barrio report no relevant financial disclosures.