Patients with Down syndrome (DS) have steeper and thinner corneas and more corneal aberrations than patients without DS, according to a study published online June 21 in JAMA Ophthalmology

Literature suggests corneal morphologic characteristics compatible with keratoconus are present in a high percentage of patients with Down syndrome (DS), suggesting the need to perform a detailed examination of the anterior segment to try to avoid serious visual impairment in this group of patients.

Down syndrome (DS) was first described by John Langdon Down in 1866. This condition is a developmental disorder caused by an extra copy of chromosome 21 and is typically caused by what is defined as chromosomal nondisjunction.

Jorge L. Alio, M.D., Ph.D., from Universidad Miguel Hernández in Alicante, Spain, and colleagues performed a multicenter case-control study to characterize the abnormal features of the cornea in 112 patients with DS and 105 healthy controls without DS. The study included 321 eyes of the 217 participants.

After clinical assessment of corneal topography, the researchers found that 71.3 percent of patients in the DS group showed evidence of keratoconus. There were differences in steepest keratometry of 47.35 diopters in patients with DS versus 43.7 diopters in control subjects. There were also differences in corneal pachymetry of 503 µm in patients with DS versus 545 µm in controls.

Keratoconus diagnosis

Patients with DS have steeper and thinner corneas and more corneal aberrations than those without genetic alterations and normal corneas. The findings suggest a detailed corneal study should be considered in such patients to detect keratoconus and implement treatment as appropriate to try to avoid serious visual impairment in this group of patients.

"The findings suggest a detailed corneal study should be considered in such patients to detect keratoconus and implement treatment as appropriate to try to avoid serious visual impairment in this group of patients," the authors write.

. These observations should be considered when examining patients with DS to detect possible changes associated with corneal ectatic disorders, especially now that therapeutic alternatives exist for the control of the evolution of keratoconus to advanced stages in which visual loss is a frequent endpoint complication that may limit further the quality of life of these patients.

Finally, it seems necessary to conduct long-term prospective studies to further complete and understand better the findings from this investigation and to define new and more adequate medical diagnostic and therapeutic standards to prevent severe visual impairment owing to corneal ectatic disorders in patients with DS.