Clinical applications of an automated test of colour vision.
The early detection of acquired losses of colour vision can provide the
ophthalmologist with a very sensitive indicator of visual dysfunction. As
a result we have developed and tested an automated, CRT-based,
chromatic discrimination system that allows us to measure acquired
colour-vision deficits with great precision. This system, known as the
Sussex Gratings Machine, can produce chromatic stimuli in any
direction in equal luminance colour space. However, we have found that
measurements made along a constant MIL-cone axis (Tritan) or a
constant S-cone (Red/Green) confusion axis are most useful.
Using this system we have investigated acquired colour vision deficits in
diabetes ,. and thyroid eye disease. We have shown that tritan
discrimination losses can be used to screen for severe diabetic
retinopathy and also to predict those who are likely to develop it within
18 months. We have also confirmed that acquired tritan discrimination
losses are a very useful indicator of optic-nerve compression in thyroid