Corneal characteristics in Down syndrome patients with normal and keratoconic cornea

PurposeTo determine the reference range of corneal indices in Down syndrome patients with normal corneas (DS-N) and to compare it with the corneal indices in Down syndrome patients with keratoconic corneas (DS-KC). MethodsA study was conducted using the data of 154 eyes of 154 DS-N and 25 eyes of 25 DS-KC patients. Eighteen indices related to thickness, anterior chamber, keratometry, elevation, and aberrations routinely used for KC diagnosis were extracted from the Pentacam. ResultsThe mean age of the participants in DS-N and DS-KC groups was 16.73 +/- 4.70 and 16.56 +/- 4.22 years (P = 0.852). In the DS-N group, 95% CI were 511.65-520.31 for minimum corneal thickness, 2.97-3.07 for anterior chamber depth (ACD), 46.83-47.37 for maximum keratometry (Kmax), 46.13-46.62 for zonal Kmax at 3 mm, 0.35-0.58 for inferior-superior asymmetry (I-S value), 1.56-1.88 for Belin/Ambrosio display-total deviation, 8.65-10.79 for best-fit-sphere posterior elevation at the thinnest point, and 0.18-0.22 for corneal vertical coma. The age-related change in I-S value and corneal spherical aberration (SA) was significant (both P < 0.05). There were significant inter-gender differences in 11 indices; the female DS patients had shallower, steeper, more elevated, and more aberrated corneas (all P < 0.05). There were significant differences in all indices except for ACD (P = 0.372) and corneal SA (P = 0.169) between DS-N and DS-KC groups. ConclusionIn DS patients aged 10-30 years, the reference ranges of corneal indices are different from the range reported for non-DS subjects and are close to values reported for mild KC non-DS cases. The normal values are different between DS male and female; hence, sex-specific ranges should be considered for diagnosis of corneal abnormality in DS patients.

Automated summary

This study aimed to determine the reference range of corneal indices in Down syndrome patients and found that the reference ranges of corneal indices are different from non-Down syndrome subjects and are close to values reported for mild keratoconus cases. The study also highlighted the importance of considering sex-specific ranges for diagnosing corneal abnormalities in Down syndrome patients.