Early Evaluation and Treatment
Early evaluation and treatment is critical when teaching children with developmental disabilities and visual impairment in order for children to develop visual perceptual skills. Children do not need to be able to communicate verbally in order to have vision evaluated because a machine called a retinoscope gets an accurate prescription for refraction errors that cause blurriness. In fact, optometrist Dr. Mitchell Sheiman recommends that children be evaluated at ages six months, three and five years of age to rule out the following problems:
- Visual acuity (ability to focus)
- Binocular vision (using eyes together)
- Accommodation (ability to see objects at different distances)
- Strabismus (eyes turning inward or outward)
- Eye movements (such as tracking or scanning)
Whereas, most parents are quick to notice when their children have myopia (difficulty seeing distance) – it is less obvious when children struggle with hyperopia (seeing up close). Hyperopia interferes with learning because children have difficulty identifying nearby objects and pictures and discriminating shapes and letters.
Visual Impairments Associated With Developmental Disabilities
Children with developmental disabilities are especially at risk for visual impairment that impacts learning. Children with the following diagnoses have higher than normal rates of the following visual disorders:
- Down’s Syndrome (myopia, hyperopia, strabismus)
- Cerebral palsy (strabismus, significant refractive error, accommodative disorders)
- Autism spectrum disorders (strabismus, myopia, hyperopia, astigmatism)
Other less common disorders include: ptosis (drooping eye lid), abnormal head posture and amblyopia (lazy eye). Fortunately, many visual impairments can be treated to improve a child’s abilities to develop visual perceptual skills and learn academics.
According to Dr. Scheiman 50- 60% of children with developmental disabilities should be wearing glasses at birth. Eye glasses or prism lenses can correct myopia, hyperopia or astigmatisms (difficulty with near and distance focus). To treat amblyopia an optometrist may patch the stronger eye to force the child to use the weaker eye.
Exercises may help children with difficulty using the eyes together to track and follow objects moving toward and away from the face (convergence and divergence). Sometimes surgery is performed to improve eye muscle disorders such as strabismus. Occupational therapists also treat children with vestibular (balance) based visual disorders using sensory integration therapy.
Environmental Adaptations and Activities
Young children should be encouraged to spend time looking at objects at different distances (including trees and stars) and avoid long periods of watching television and computer screens. Home and school adaptations that may be helpful include:
- Angling or raising work and/or reading surfaces
- Avoiding glare
- High color contrast
- Enlarging materials
- Avoiding clutter
Playing games that involve catching, throwing at a target, swatting at moving objects such as bubbles or “tagging" other children with a flashlight promote visual skills. When children with developmental disabilities are given early treatment to correct visual impairments, provided environmental adaptations and activities to promote visual skills, they will be given the tools to learn to the best of their abilities.
- Scheiman, Mitchell, “Understanding and Managing Vision Deficits”, N.J.: Slack Inc.,1997.