Eyes and Vision

Disclaimer: This information sheet is for education purposes only. Please consult with your doctor or other health professional to make sure this information is right for your child.

What can happen?

The visual system is large and complex. It travels from the eyeball to the occipital cortex at the back of the brain see Figure 1. The occipital lobe of the brain is the area of the brain where information processed by the eyes is decoded and information about what we see (colour, shape and distance) is understood.

Figure 1: Lobes of the brain.

Injury to any part of this pathway can lead to problems with eyes and vision see Figure 2. Information is received by the eyeball and then transferred in special nerves to the back of the brain to be decoded into what we "see". Problems with eye positions (squint or strabismus, double vision), eye movements (jerky eyes, nystagmus, poor tracking), visual field defects and vision problems commonly occur following a brain injury. Over time the visual difficulties tend to improve.

Figure 2: Visual pathways

What are the symptoms?

Double vision (Diplopia) is due to an imbalance of the eye muscle movements. The two images, one from each eye, are not aligned properly and so the child interprets this as a double image. A child may close or cover one eye to "look" at something or have difficulty with balance or judging depth. They may have difficulty reading and copying. The child may have a squint or turn of one their eyes.

Visual Field Defect (hemianopia or homonymous hemianopia) is due to interruption of the visual pathways in the brain and results in loss of vision in one half of each eye like one of two curtains being half drawn across a window see Figure 3. A child may not pay attention to one side, may bump into objects on a particular side of the body or only draw on one side of a page.

Figure 3: Visual field defects - depend on the area of the visual pathway damaged

Poor visual acuity occurs when you cannot see clearly. This is tested by using the eye charts where the child reads letters or pictures. Special tests are available to test those children who cannot name pictures or read letters. A child may have difficulty naming a familiar object or person or have difficulty seeing clearly.

Squint (strabismus) - adopting various head postures to try and line the eyes up by moving the head as the eyes cannot correct the position themselves.

What is the treatment?

Eyeball problems

If the problem with vision is due to an eyeball problem sometimes glasses can help, this is not common following a brain injury. Usually strategies to compensate for the limitations are needed while the childs eyes and vision recover.

Double vision

Patching one eye can relieve the double vision, it is important to alternate eyes with the patch so that one eye is not weakened by lack of use. Patching can also help strengthen the muscles causing a squint. Here the eye with better vision is patched and the weaker eye made to work and straighten its position.

Poor visual acuity

Children may need their school worksheets enlarged or made less cluttered to help them see the work more easily. Enlarging pictures and writing can help. Having well contrasted pictures in books. Using felt tipped pens for drawing and writing makes a thicker more easily seen line. Good lighting and good seating for school-work and sometimes using a slope board on desks can help especially if the child has difficulty looking down. If a child has a very severe vision impairment involvement of the Royal Blind Society is appropriate. They are a service for persons with impaired vision who provide a comprehensive service for home and school to address difficulties with vision.

Visual field defects

Teaching children to look/scan left and right will help them be aware of people or objects in their "blind spot".

Who do I see and how is it diagnosed?

Your local doctor, paediatrician or neurologist can assess eyes and vision. An ophthalmologist is a doctor who specialises in disorders of the eye. An orthoptist is a person who specialises in assessment of eyes and vision. Both an ophthalmologist and an orthoptist see most children who have difficulties with eyes and vision after a brain injury.

Rehabilitation Department The Children's Hospital at Westmead Cnr Hawkesbury Rd & Hainsworth St, Westmead Locked Bag 4001, Westmead, 2145 Tel: (02) 9845 2132 - Fax: (02) 9845 0685 http://www.chw.edu.au/rehabilitation/