Down Syndrome is a condition describing a collection of symptoms related to an additional copy of chromosome 21. (1) This common diagnosis has many common characteristics but this term hardly captures the determined, stubborn and loving children that we treat in the clinic. Fine motor problems and low tone are common but visual problems are also affecting the functional ability of these children.
The Vision Problems Associated with Down Syndrome
Our children with DS have many ocular problems at a higher incidence than that of neurotypical children. The most common being a higher incidence of far-sightedness and astigmatism(2) making the need for a complete dilated exam and more frequent eye exams. Also common are accommodative problems(3), which would affect the ability of the child to focus on items up close. These unique combinations of pathologies require an optometrist or ophthalmologist experienced with the visual needs of these special children. In spite of glasses and thorough assessment, our children with DS still have visual problems and delayed development of visual skills(4) possibly related to some degree of cortical visual impairment(5). All of these visual problems are linked to functional problems. These problems are just the beginning of the vision problems associated with Down Syndrome.
Functional Problems associated with Vision in Down Syndrome
The common problems of farsightedness make for a difficult time with fine motor and handwriting skills as the child sees poorly up close. Add to this the smaller hands and reduced thumb size common in our DS friends it is easy to understand why they become frustrated with near and fine motor tasks.
These near vision problems can also lead to problems with perception of the floor as they learn to walk and crawl. The common loss of lower visual fields in CVI makes walking a scary prospect of our friends as they may not see changes in the floor surface(6). Correction for near vision, weather a bifocal or a complete lens with (+) power, can also cause some distortion of the floor and other surfaces.
The higher rate of astigmatism can also cause problems of perception of visual space as visual space can become twisted, possibly leading to head tilts or other head postures as the brain attempts to correct for these.
When these conditions go undiagnosed and uncorrected, the visual problems multiply, limiting visual pathway development and binocular depth perception. Even when appropriately corrected, the child with Down Syndrome may remain six months to a year behind concerning developing visual skills.
Glasses and Down Syndrome
The special facial features frequently associated with DS can also provide a challenge for the optician. Specs4Us makes glasses with special modifications to make glasses fit better on our patient with Down syndrome.
Given the frequency of near vision problems, it is most important the glasses stay in place when looking down. An experienced optician can be very helpful with assuring our children to get the best possible fit to get the biggest benefit from their glasses.
(1) “Facts about Down Syndrome.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 1 Nov. 2018, https://www.cdc.gov/ncbddd/birthdefects/downsyndrome.html.
(2) da Cunha, R P, and J B Moreira. “Ocular Findings in Down’s Syndrome.” American Journal of Ophthalmology, U.S. National Library of Medicine, Aug. 1996, https://www.ncbi.nlm.nih.gov/pubmed/8694092.
(3) Haugen, Olav H, et al. “Ocular Changes in Down Syndrome.” Tidsskrift for Den Norske Laegeforening : Tidsskrift for Praktisk Medicin, Ny Raekke, U.S. National Library of Medicine, 22 Jan. 2004, https://www.ncbi.nlm.nih.gov/pubmed/14743234.
(4) Purpura, Giulia, et al. “Visual Assessment in Down Syndrome: The Relevance of Early Visual Functions.” Early Human Development, U.S. National Library of Medicine, Apr. 2019, https://www.ncbi.nlm.nih.gov/pubmed/30818135.
(5) Little, Julie-Anne, et al. “Vernier Acuity in Down Syndrome.” Investigative Ophthalmology & Visual Science, U.S. National Library of Medicine, Feb. 2009, https://www.ncbi.nlm.nih.gov/pubmed/18824732.
(6) “Cortical Visual Impairment Pediatric Visual Diagnosis Fact Sheet.” Cortical Visual Impairment Pediatric Visual Diagnosis Fact Sheet, http://www.tsbvi.edu/seehear/fall98/cortical.htm.