1. Visual Performance and the use of Coloured Filters in Deaf children
Peter Allen1, Richard Hollingsworth1, Amanda Ludlow2, Richard Calver1, Arnold Wilkins3
1Dept. Vision and Hearing Sciences & Vision and Eye Research Unit, Anglia Ruskin University, 2Dept. of Psychology, University of Hertfordshire, 3Dept. of Psychology, University of Essex
Purpose:
Purpose: Learning to read involves an integration of language and visual skills.1 Deaf children struggle with reading acquisition more commonly than hearing children partly because of phonological deficits but also perhaps because of the visual deficits with which deafness is associated. We assessed vision and visual performance, and the effects of coloured overlays on the rate of reading in deaf and hearing children.
Methods:
Thirty-one deaf and 39 hearing children underwent an extensive optometric examination with specific emphasis on near vision that included (in order): vision and visual acuity, subjective refraction, assessment of heterophoria, near point of convergence, amplitude of accommodation and Pattern Glare. Non-verbal Intelligence quotient (IQ) was assessed with the Raven’s Standard Progressive Matrices. Participants chose an overlay with colour optimal for clarity and comfort and completed the Wilkins Rate of Reading Test both with and without an overlay of this colour.
Results:
Deaf participants had greater ametropia compared to a matched normal hearing population. Deaf participants also had a significantly more distant near point of convergence and a reduced amplitude of accommodation. The Ravens IQ (standard deviation) for the deaf and hearing groups were 95.4 (30.6) and 88.7 (11.8) respectively. There was no significant difference in age or IQ between groups. All of the deaf children chose a coloured overlay. Forty five percent (14/31) chose a yellow overlay, and for these children there was a significant increase in rate of reading with the overlay. In contrast, only 66% (26/39) of hearing participants chose an overlay and this had no significant effect on reading speed.
Conclusions:
The findings confirm earlier research in showing that visual deficits are common in deaf children.3 A yellow overlay significantly improved reading speed for the deaf children, whereas other colours did not, a finding at variance with earlier work on hearing populations,4 and suggestive of a magnocellular deficit. The deaf are doubly disadvantaged by reduced visual and phonological skills that impair reading.
References
1Castles A, Coltheart M. Is there a causal link from phonological awareness to success in learning to read? Cognition 2004; 91:
2Musselman C. How do children who can't hear learn to read an alphabetic script? A review of the literature on reading and deafness. J Deaf Stud Deaf Educ. 2000; 5: 9-31.
3Hollingsworth R, Ludlow AK, Wilkins AJ, Calver RI, Allen PM. Visual performance and ocular abnormalities in deaf children and young adults: a literature review. Acta Ophthal (in press).
4Wilkins A. Coloured overlays and their effects on reading speed: A review. Ophthalmic Physiol Opt. 2002; 22: