Abstract
Introduction: Adults with amblyopia have been shown to experience monocular and dichoptic distortions of their visual perception. The current study aims to measure for the first time dichoptic distortion in children with amblyopia undergoing routine amblyopia treatment, and relate measured perceptual visual distortions to amblyopia features and clinical outcomes of amblyopia treatment. Methods: Children undergoing standard amblyopia treatment had perceptual visual distortion measured within the central 5° of the visual field. The task was mouse-based target-clicking on a stereoscopic LCD monitor, viewed dichoptically through active shutter glasses. The amblyopic eye viewed the cursor and fellow eye the target dot (presented in 16 locations). Global distortion index (mean vector displacement in degrees of mouse-click location from target dot location) was compared to age-matched control children without amblyopia. Results: Amblyopic subjects (n = 13, mean age 6.19 ± 0.99 years) had a significantly greater global distortion index than age-matched control children (n = 140) (0.76° ± 0.56°, vs. 0.41° ± 0.12°, p = 0.001). Global distortion index appears affected by amblyopia type: strabismic/mixed amblyopia was associated with the highest global distortion index (1.00° ± 0.73°), followed by microtropic amblyopia (0.68° ± 0.27) and anisometropic amblyopia (0.41° ± 0.26°). It was not significantly correlated with interocular acuity difference at treatment commencement, number of lines VA improvement, treatment duration, or current VA/refractive error in either eye. Conclusions: Children who have undergone amblyopia treatment experience distorted perception under dichoptic viewing conditions, independent of the VA improvement gained from standard amblyopia treatment practices. These findings suggest that current amblyopia treatment regimens aimed at improving VA/contrast sensitivity do not address the behavioural consequences of utilising amblyopic vision.
Meeting abstract presented at VSS 2014