Individuals with Down syndrome (DS) may have different anterior and posterior corneal apex dynamics compared with individuals with keratoconus (KC) who do not have DS, according to research published in Eye and Vision. These properties include an anterior apex that tends to displace more prominently and a more stable posterior apex among individuals with DS compared with individuals with KC without DS.
Researchers included 43 individuals with DS (mean age, 24.3 years) and 99 age- and sex-matched control group participants with KC and no DS (mean age, 27.1 years) in a cross-sectional study between 2017 and 2019 to assess corneal morpho-volumetric features in individuals with DS. Participants underwent higher-order aberration (HOA), central corneal thickness, and spherical error refraction (SER) measurements and morpho-volumetric parameter assessment using a 3D corneal model. Individuals with DS were stratified according to the presence of KC topography (n=16) or absence of KC topography (n=27).
The individuals with DS had significantly less mean HOAs compared with control group participants (1.22 vs 1.44 μm; P =.004).
Overall, a greater deviation in the anterior corneal apices, area of the anterior and posterior surfaces, anterior corneal apices, and center of mass X-axis coordinates of the solid were observed among individuals with DS compared with participants without DS (P ≤.018 for all). Conversely, lower values for the posterior corneal apices and center of mass Z-axis coordinates of the solid were observed among individuals with DS compared with those without the condition (P ≤.012 for both).
The subgroup analysis consisting of individuals with DS stratified according to KC topography revealed that age, SER, and HOA were higher among the subset of participants with KC and posterior corneal apices and posterior corneal minimum thickness point were lower among these individuals (P <.05 for all).
“DS corneas have a different topographical and morpho-volumetric profile from non-DS corneas,” according to the researchers “This reinforces the theory already raised by our group that corneal structure and anatomy are specific features of all DS cases, predisposing them to a number of corneal pathologies that influence the stability of their corneas which consequently challenges their quality of vision along their lives.”
Study limitations include a limited number of individuals with DS in the study sample.
Disclosure: Some study authors declared affiliations with the biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
Toprak I, Cavas F, Velázquez JS, Alio del Barrio JL, Alio JL. A three‑dimensional morpho‑volumetric similarity study of Down syndrome keratopathy vs. keratoconus. Eye Vis. Published online January 3, 2023. doi:10.1186/s40662-022-00315-0