Decreased central corneal thickness in children with Down syndrome

Purpose: A cross-sectional, masked, case-control study was undertaken to investigate whether central corneal thickness is affected in children with Down syndrome and to focus on its clinical significance. Participants and Methods: Twenty-eight children with Down syndrome (15 boys and 13 girls) aged 5 to 15 years and 20 age-matched and gender-matched healthy control subjects (11 boys and 9 girls) from a similar ethnic background were enrolled in the study. Central corneal thickness was measured by ultrasound pachymetry. Only the right eye of each child in each group was included in the statistical analysis. The Mann-Whitney U test was used and a P value of less than .05 was considered significant. Results: The mean ages of the children with Down syndrome (9.28 +/- 3.47 years) an and the healthy control subjects (8.75 +/- 3.30 years) were comparable (P > .05). Central corneal thickness values were below 500 pm in 19 (67.8%) of the 28 children with Down syndrome, 4 of which were less than 450 pm. However, all central corneal thickness measurements in the control eyes were more than 500 pm. The mean central corneal thickness in the children with Down syndrome was significantly (P < .001) less (488.39 +/- 39.87 mum) than that in the healthy control subjects (536.25 +/- 20.70 mum). Mean keratometric values were significantly (P < .001) higher in the eyes of the children with Down syndrome (46.35 +/- 1.28 D) than in the eyes of the control subjects (43.32 +/- 1.15 D). Conclusions: Children with Down syndrome had a decreased central corneal thickness compared with healthy control subjects. Decreased central corneal thickness may give an artificially low intraocular pressure measurement by applanation tonometry. Central corneal thickness must be considered when developing, approaches for keratorefractive treatment of patients with Down syndrome.