Visual requirements for reading
Whittaker, Stephen G. & Lovie-Kitchin, Jan E. (1993) Visual requirements for reading. Optometry and Vision Science, 70(1), pp. 54-65.
We have applied research on the visual psychophysics of reading to low vision assessment. Research on different aspects of the reading process found that reading rate rather than reading comprehension is more sensitive to variations in a subject’s visual functioning or the stimulus properties of print. The research identified four different visual factors that significantly affect reading rate: (1) acuity reserve [print size relative to acuity threshold], (2) contrast reserve [print contrast relative to contrast threshold], (3) field of view [number of letters visible], and (4) in cases of maculopathy, central scotoma size. Our research indicates that fluent reading rates can be attained with a restricted field of view, as little as four characters. However, attainment of fluent reading levels requires that print size and contrast should be several times threshold and the diameter of a central scotoma should be less than 22°. Although important clinical studies are lacking, we derived specific visual requirements for different reading rates from published experimental research to provide a starting point and to illustrate how visual requirements could be derived, even with poor correlations. Research has made significant progress toward the development of a comprehensive low vision assessment that will allow the practitioner to identify visual impediments to reading, other than reduced visual acuity. Having more fully characterized a visual impairment, the practitioner may tailor devices or interventions to the individual’s needs and capabilities.
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|Item Type:||Journal Article|
|Keywords:||reading, low vision, visual psychophysics, visual acuity, print size, contrast sensitivity, print contrast, field of view, scotoma, maculopathy, macular degeneration, retinal disease|
|Subjects:||Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > OPTOMETRY AND OPHTHALMOLOGY (111300)|
|Divisions:||Current > QUT Faculties and Divisions > Faculty of Health|
Current > Institutes > Institute of Health and Biomedical Innovation
Current > Schools > School of Optometry & Vision Science
|Copyright Owner:||Copyright 1993 Lippincott Williams & Wilkins|
|Deposited On:||01 Dec 2006|
|Last Modified:||19 Oct 2012 09:41|
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