F Eperjesi¹, C W Fowler¹, B J W Evans²
¹Aston University, Neurosciences Research Institute, Birmingham, United Kingdom; ²Institute of Optometry, Optometry, London, United Kingdom
Background
Colour vision analysis is not routinely conducted in low vision practice and colour vision does not play a major role in management. This could be because appropriate tests for colour vision analysis are not readily available. We describe how the Intuitive Colorimeter (an instrument that allows the independent manipulation of hue, saturation and intensity) can be used to determine colour discrimination on an individual basis and thereby assist rehabilitation.
Method
Twelve ARMD subjects were instructed to view a black-on-white cross wire target with a 22 cm² viewing area (60 degree field) placed inside an Intuitive Colorimeter wearing their near refractive correction. No subject had any congenital colour vision deficit and all testing was binocular. A neutral grey colour was presented first, a randomly selected hue was dialled into the Colorimeter and saturation increased until the observer could just detect a change from the neutral grey. A note was made of the saturation at this point. Intensity remained constant throughout the testing session, only hue and saturation were varied. This procedure was repeated, colour was sampled every 30 degrees on the hue wheel (an arbitrary scale) and results for 13 colour conditions were plotted as a chromatograph in the form of a polar diagram for each subject.
Results
Each polar plot highlighted a range of colour saturations that could not be discriminated from the initial neutral grey i.e. the polar plot depicted a colour vision scotoma. Colours outside these scotomas could be more easily discriminated. Seven ARMD subjects demonstrated scotomas all with blue-yellow orientation axes.
Conclusions
Polar plots generated by the Intuitive Colorimeter can be used to obtain information about functional colour vision loss. These plots can be used to indentify groups of colours that optimise colour discrimination and thereby aid rehabilitation.
Return to the ISLRR.ORG Home Page
