Individuals need several important visual skills to participate successfully in daily activities and routines at home, school and work. Vision is more than a person’s ability to see things near or far away clearly. This article will provide an overview of all aspects of vision; review the concepts of visual integrity, visual efficiency and visual processing; and highlight some visual skill deficits that are more common in individuals with Down syndrome.
When most people think of vision, what they are thinking of is visual acuity (whether your vision in 20/20), refraction (whether you are near or far sighted or have an astigmatism), as well as your overall eye health and visual fields. Research shows that individuals with Down syndrome have an increased prevalence of visual integrity disorders including myopia (nearsightedness), hyperopia (farsightedness) and cataracts. Cataract refers to a clouding of the lens (the transparent, front of the eye). Most cataracts are related to aging, however individuals with Down syndrome are more likely to develop a cataract at or near birth. The presence of a cataract will blur or “fog” an individual’s vision.
Visual efficiency refers to the effectiveness of the visual system to gather visual information clearly, efficiently and comfortably. Eye movements and binocular vision skills (the ability of the eyes to work together as a team) are the primary visual efficiency skills. There is a higher prevalence of strabismus in individuals with Down syndrome.
Strabismus refers to the alignment of the eyes and impacts the ability of the eyes to work together as a team. With a strabismus, one or both eyes can turn in toward the nose, turn out toward the ears, turn up or turn down. Strabismus can be present constantly or only sometimes such as when an individual is tired or gazing in a specific direction.
By one month of age, eye alignment should be normal. The presence of strabismus in a child aged 6 or younger should be addressed by an eye doctor. Strabismus is often considered a cosmetic problem; however untreated strabismus can lead to amblyopia which is a loss of vision in one eye due to suppression. If an individual’s eyes are not working together as a team, young brains will ignore input from the eye that is misaligned to avoid double vision – this is called suppression. This can become a permanent loss of vision if not addressed. Treatment often includes patching, prism glasses or surgical repair.
The final visual concept to review is visual processing, which is broken down further into visual perception skills and visual motor integration skills. Visual perception includes your ability to tell the difference between forms and shapes, remembering what you see, understanding how objects relate to each other in space, and the ability to find an object hidden in a busy environment. Difficulties with visual perception skills can negatively affect school performance as these skills can impact the ability to learn letters and numbers, retrieve key information and organize schoolwork and space. Visual motor integration is the ability of the eyes and hands to work together in smooth, efficient patterns. Visual motor integration skills allow individuals to perform daily activities such as getting dressed, managing buttons and tying shoes; and is linked with learning to write and cut with scissors.
What does all this mean to a parent of a child with Down syndrome?
The American Academy of Pediatrics recommends that children with Down syndrome receive regular eye examinations. The initial visual evaluation should be done by 6 months of age and then follow up evaluations done every year after that. As you support your child’s continued growth and development, consider if vision is playing a part in their success or if it is creating challenges with new skill acquisition. Discuss the role of vision on your child’s development with their medical providers, therapy teams and school personnel. If visual challenges are suspected, arrange for a comprehensive vision evaluation that evaluates all the visual skills mentioned here.
Jordan Porter, MS, OTR/L, is an occupational therapist on the rehabilitation team at Children’s Hospital of Philadelphia.