Clinical testing for amblyopia
Amblyopia occurs when the nerve pathway from one eye to the brain does not develop during childhood. This occurs because the abnormal eye sends a blurred image or the wrong image to the brain. The test for assessment of visual neural development in infants and young children employs a rapid sweep of stimuli (bars of different widths - different spatial frequencies) to efficiently and objectively measure neural mechanisms of spatial vision. VEPs in response to the sweep stimuli are recorded monocularly. A multivariate statistical algorithm calculates the signal-to-noise ratio at each spatial frequency, and then tests the significance of the difference between the fellow-eye data. Visual (grating) acuity is calculated automatically from each eyes' responses. The complete test, including both eyes, takes about four minutes. A result based on a statistical analysis across all the spatial frequencies is available, which can simplify the interpretation. Visual acuity estimation displayed in Snellen chart system is also available.



The plot depicts a spatial frequency VEP test result. There is a significant difference in the responses obtained from stimulation of left (blue) and right (red) eyes.