Vision Problems in People with Down Syndrome

Vision disorders are common in Down syndrome with over 50% requiring glasses for treatment. It is important that those supporting the individual know what the glasses are for. Many people require two sets of glasses and it can be helpful to have their purpose etched on the side of the frame, for example R - reading and LV - long vision.

How the Eye Works


LiveScience Graphic Image courtesy of 3DScience.com The eye works by light passing through transparent parts and projecting an image on the back of the eye (the retina).  Light firstly passes through the cornea (the clear outer part of the eye).  The cornea bends the light (focuses).  The light then travels through the watery fluid (Aqueous humor) that fills the space between the cornea and the iris.  The iris gives our eyes their colour.

At the centre of the iris is a hole called the pupil. The iris either contracts or dilates to make the pupil smaller or larger, depending on the light.  Situated behind the pupil is a colourless, transparent structure called the lens. Muscles surround the lens.  The muscles hold the lens in place but also play an important role in vision.

Light is further bent through the lens, and changes its shape according to whether the object looked at is near or far.  The light travels through the aqueous humor and is then projected onto the retina.

The retina is the innermost of three tissue layers that make up the eye. The outermost layer, called the sclera, is what gives most of the eyeball its white colour. The cornea is also a part of outer layer.  The middle layer between the retina and sclera is called the choroid. The choroid contains blood vessels that supply the retina with nutrients and oxygen and removes its waste products.
The image is converted into an electric signal that is sent to the brain by the optic nerve. The brain then translates the electrical signals into the images we see.  The macular is the most sensitive part of the retina and is responsible for fine vision tasks.  The rest of the retina provides peripheral (all round) vision. Focusing errors (long-sight and short-sight) are caused by light converging behind or in front of the retina rather than on it.