Spectral filters can improve reading and visual search in patients with multiple sclerosis

We investigated the possible benefit for 26 patients with multiple sclerosis of placing Intuitive Overlays (spectral filters) over the page during reading and visual search. Initially all patients were allowed to select an overlay of a colour that reduced perceptual distortion and were tested with and without that overlay. With the coloured overlay, 25/26 patients reported fewer symptoms of visual stress, 50% read at least 20% more quickly and 50% omitted at least 57% fewer targets during visual search. Subsequently, under double-masked conditions 13 randomly-selected patients were given grey overlays,while the remaining 13 gender- and agematched patients were each given an overlay of their individually selected colour. Patients were permitted to use their overlays as and when they wished during the next 2 weeks. The reading and visual search performance of those patients who had received a grey overlay did not change,whereas the performance of those who received an overlay of their selected colour subsequently improved, both when using the overlays and also when not. After testing, the 13 patients who had received a grey overlay returned it prior to subsequent testing. The 13 patients were then each given an overlay of their selected colour and their performance subsequently improved.A large proportion of patients with multiple sclerosis may benefit from the use of spectral overlays.