Perceived effects of coloured overlays on reading material in persons with albinism

Abstract

Persons with albinism often complain of glare when reading. They may therefore benefit from coloured filter overlays just as they benefit from tinted lenses. The purpose of this study was to assess the effectof coloured overlays on print perception in persons with oculocutaneous albinism (OCA).   Fifty subjects were included in this study, their ages ranged from 12 to 31 years with a mean of 16.12 years (SD = ± 4.56 years).  Following refraction and subsequent compensation for refractive errors, subjective perception of print was examined with the subject looking at the Wilkins® reading rate test chart with and without colored filter overlay/s.  The subjects were asked to respond to questions previously used in a questionnaire by Wilkins (2001). The percentage frequencies of positive (beneficial) responses were used to decide whether or not a particular overlay would enhance reading performance.  McNemar’s test was used to establish significant differences between responses to questions without and with overlays. All single overlays gave greater percentages of positive responses (92.0-97.2%) than without overlay (85.2%).  The single overlay that provided the highest positive responses
was blue (97.2%) and the least was purple (92.0%). All double overlays, except grey/grey (82.0%) gave greater positive responses than without overlay (85.2%). Aqua/blue gave the greatest positive responses (possible benefits) (97.2%), followed by rose/rose (96.8%).  Comparing the responses without overlay with single and double overlays, the difference in responses to the five questions was only significant (p < 0.05) with regard to brightness of the surface. The results suggest that overlays provided a more glare-free reading surface than without an overlay. It was, therefore concluded that the best advantage of the coloured overlays was in glare reduction.  Although this study showed that
there were more subjects who preferred single blue and aqua/blue double overlays, inter-subject preference for overlays varied, therefore the best overlay should be established for every patient for whom overlay is to be prescribed.