Higher Order Aberrations in Children with Down Syndrome

Purpose: Down syndrome (DS) is associated with ocular abnormalities and reduced visual function. Studies report atypical optical structures in the DS eye such as thinner, steeper corneae and thinner crystalline lenses and, functionally, a degrading influence of the optics on resolution acuity. The present study further investigates optical quality in DS by comparing higher order ocular aberrations (HOA) in DS and control eyes.Methods: Participants were 44 children with DS (6-16 years) and 209 age-matched controls. All participants were free from corneal or lenticular pathology. HOA were measured following cycloplegia using Shack-Hartmann aberrometry. HOA were analysed over a 3mm and 5mm pupil using Zernike polynomials from 3rd to 6th order. Optical quality was explored using Visual Strehl ratios (VSX) and equivalent defocus values. Results: HOA were measured successfully from 68% of the DS group and 95% of controls. Root mean square of total combined HOA, third and sixth orders and coma were significantly greater in the DS group (p