Abstract
Purpose:
Deaf children have phonological deficits that impair reading acquisition but also have visual deficits that make reading even more difficult. This study assesses 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. 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. Finally the non-verbal Intelligence quotient (IQ) was assessed with the Raven’s Standard Progressive Matrices.
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. 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. There was no significant difference in age or IQ between groups.
Conclusions:
The findings confirm earlier research in showing that visual deficits are common in deaf children. 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, and suggestive of a magnocellular deficit.
Keywords: 434 binocular vision/stereopsis •
640 pattern vision •
579 learning