The CAD test screens for normal red/green (RG) colour vision in less than one minute. If loss of RG colour vision is detected, the CAD test can measure accurately the severity of RG colour vision loss and quantify the class of deficiency involved (i.e., protan- or deutan-like deficiency) in less than 6 minutes.
Subjects born with yellow/blue (YB) deficiency (i.e., congenital YB deficiency) are very rare (about 1 in 15,000), but the prevalence of acquired YB sensitivity is much higher and increases with age. The CAD test can also quantify the severity of YB colour vision loss in less than 6 minutes and can diagnose accurately acquired colour deficiency. The latter is often associated with systemic and/or eye disease and preliminary data suggest that in cases of age-related macular degeneration (ARMD) and diabetes, the loss of chromatic sensitivity can precede the clinical detection of retinopathy by several years.
Very early detection of subclinical retinal changes that lead to retinopathy and the use of treatment regimes to slow down the rate of progress of ARMD are of great interest in the public health arena. The CAD test detects significant changes in the patient's chromatic sensitivity over time and this can be used to monitor progression of disease and/or effects of treatment.