Importance: Keratoconus disproportionately affects people with Down syndrome (DS). This is the first study of its kind in Australasia.
Background: To investigate the prevalence of keratoconus in DS.
Design: Cross-sectional study.
Participants: Athletes with DS attending 2017 New Zealand Special Olympics National Summer Games.
Methods: Keratoconus was identified using corneal topography (TMS-4N, Tomey). Topography from both eyes was required to be included. Two independent quantitative criteria were used to indicate keratoconus. The first was keratoconus severity index ≥ 30%. The second, adapted from the literature, required at least four of eight topographic parameters to be abnormal. Data from the worse eye were analysed. Diagnosis in each group was subsequently confirmed qualitatively by three corneal fellowship-trained ophthalmologists. Those with a definitive diagnosis were grouped into Keratoconus Confirmed Group 1 (KCC1) and Keratoconus Confirmed Group 2 (KCC2), respectively.
Main outcome measures: Keratoconus prevalence, severity, demographics.
Results: Of 110 athletes screened, N = 98 were included, mean age 30.0 ± 9.7 years. Using only topographic data, keratoconus was identified in 39 (39.8%) athletes by quantitative topographic criteria 1, and in 63 (64.3%) athletes by criteria 2. Keratoconus was confirmed by qualitative sub-specialist review in 30 (30.6%) (KCC1) and 38 (38.8%) (KCC2) athletes, respectively. Mean keratometry in groups KCC1 and KCC2 were 48.4 ± 3.2D and 48.2 ± 2.9D, respectively. Most were male (KCC1 63.3%, KCC2 76.3%) and of European ethnicity (KCC1 80%, KCC2 78.9%).
Conclusions and relevance: We report keratoconus in 30.6% to 38.8% of athletes with DS; therefore, we believe keratoconus screening is indicated in DS for early management.
Keywords: Down syndrome; congenital anomalies; cornea; corneal topography; keratoconus.
© 2020 Royal Australian and New Zealand College of Ophthalmologists.