Ingrid Bockelmann
Down Syndrome (Optical Involvement)
(mongolism, trisomy 21)
Down syndrome is a congenital, genetic defect in which an extra 21st chromosome is present, affecting normal development.
Parts of the Visual System Affected
Eye muscles
Corneal ectasias (bulging forward of cornea)
Iris marked with Brushfield’s spots which are harmless, small white spots.
Lens marked by congenital cataracts (lack of clearness to lens).
Retinal and optic nerve problems
Severe ptosis (eyelid droop)
Tear duct abnormalities with blockage and frequent discharge and tearing from eyes.
Infections of the eye lids.
Effects of Down Syndrome on the Visual System
Child may show signs of visual difficulty by squinting, closing one eye shut, tilting head unusually, crossing or wandering of one or both eyes, showing light sensitivity.
Refractive errors (need for glasses) include: Hyperopia – farsightedness (most have difficulty with near vision), Astigmatism, Myopia – nearsightedness, and Weak accomodation – difficulty changing focusing power of the eye from distance to near.
Nystagmus – involuntary eye shaking.
Strabismus – eye misalignment which can be overlooked due to extra folds of skin between the eyes and nose. If not diagnosed in childhood, can result in amblyopia (loss of vision known as “lazy eye”) and loss of stereopsis (use of two eyes together or depth perception).
Deprivational amblyopia – brain can never “learn” to see due to lack of clear images delivered to the brain during childhood (such as when cataracts are not quickly removed in infants and children).
Common Treatments
Evaluation of the red reflex (normal reflex of the retina when struck by light) at birth to look for cataracts and chek for strabismus or nystagmus.
First eye exam should be done by six months of age and then every one to two years.
Bifocals for refractive errors and weak accomodation.
For strabismus, use of glasses or eye muscle surgery.
Surgical opening of malformed tear ducts.
Anticipated Functional Implications of Down Syndrome
At risk for permanent poor vision if difficulties not detected in early childhood.
Low cognitive function impairs ability to express difficulties with vision.
Increased difficulty focusing on work tasks due to near vision difficulties.
References
Cassin, B., & Rubin, M.L. (Ed.). (2006). Dictionary of eye terminology (5th ed.). Gainesville, FL: Triad.
Corn, A.L., & Koenig, A.J. (Eds). (1996). Foundations of low vision: Clinical and functional perspectives. New Yok: AFB Press.
Down’s Syndrome Association Medical Series. (2007) 6. Eye problems in children withDown’s syndrome: Notes for parents &
carers. Retrieved July 1, 2009, from
Woodhouse, J.M. (2004). Vision in children with down syndrome. Retrieved July 1, 2009, from