Around 8% of UK males have red/green colour deficiency (deuteranomoly)
Acquired colour problems suggest optic nerve or retinal problems. Test colour vision when suspecting
- Optic neuritis
- Graves Orbitopathy (GO)
The simplest (and best screening) test for aquired colour defect is subjective red desaturation:
Show the patient a red top specimen bottle to each eye in turn. Ask whether the brightness and redness of the colour was the same.
For a more repeatable test, use the Ishihara colour testing book, plates 1-17.