What is albinism?
Albinism is a name used for genetic conditions that cause a person to have no pigment or less pigment than usual. Pigment is what gives our eyes, skin and hair their colour.
There are two types of albinism.
When the eyes are involved, but skin and hair colouring are normal, it is called ocular albinism (OA).
When the skin, hair and eyes are involved, it is called oculocutaneous albinism (OCA). Sometimes, the skin and hair can be pigmented enough that an individual with genetically confirmed OCA may be classified as having ocular albinism.
Both types of albinism will cause your child to have poor eyesight. Each child's vision will be affected in a different way.
Albinism can occur as part of a larger syndrome, but this is rare. Albinism does not usually cause other medical problems or cause your child to have poor health.
Your child can see but will not have perfect vision
The sharpness or clearness of what people see is called visual acuity (VA). People with albinism have low visual acuity. It is important to understand that your child can see but what they see can be unclear or blurry. Some individuals with ocular albinism are legally blind. Legally blind means that the visual acuity is worse than 20/200 in each eye.
Albinism affects the retina and the optic nerves. The retina is the inside lining of the back of the eye. It acts like a screen onto which pictures are projected. The optic nerve is like a cable that transmits the image from the eye to the brain. In eyes affected by albinism, the retina cannot produce a sharp image and the nerves do not transmit a clear image to the brain.
Imagine a picture projected onto a smooth screen. It appears as a sharp visual picture. Now, imagine the same picture is projected onto a woolly blanket. The picture will appear to be fuzzy and out of focus. Imagine that a normal retina is like the smooth screen and a retina affected by albinism is like the woolly blanket.
Characteristics of ocular albinism
Eye colour
People with albinism often have pale blue eyes because they have very little pigment in the iris. Most children with albinism do not have red or pink eyes.
Iris transillumination
When an eye doctor shines a bright light into an eye unaffected by albinism, the light bounces back out through the pupil. This is the effect that causes "red eye" in photographs. For children with albinism the light comes through the iris as well as the pupil. This is called iris transillumination. Most likely only the eye doctor will be able to tell if your child has iris transillumination.
Nystagmus
Nystagmus (say: na-STAG-mass) causes the eyes to "shake" or move rapidly. The eyes may move side to side, up and down or in a circle. Most children with albinism have some form of nystagmus. The shaking decreases with age and will usually stop by the time your child is seven.
People sometimes think that nystagmus causes children to see a "moving world". This is a myth.
Chiasmal misrouting
In the eyes of a person without albinism, the optic nerve leaves each eye and goes to the centre of the brain. This is where the pathways from each eye meet in a structure called the optic chiasm. At the chiasm, about half of the nerve fibres travel to the opposite side of the brain from where they started. The other half travel to the same side of the brain as they started. The crossing of the nerves helps us see properly and transmit images from the eye to the brain.
For a person affected with albinism, the nerves split unevenly. For example, instead of half going to each side of the brain, 30 per cent may go to one side and 70 per cent to the other. This is called chiasmal misrouting.
Most people with albinism have chiasmal misrouting. It is uncommon in people who do not have a form of albinism. To find out if your child has chiasmal misrouting the eye doctor will do a test called a visual evoked potential (VEP).
Light sensitivity (photophobia)
Most people with albinism are sensitive to bright lights as they lack pigment in the ocular structures to absorb light. This can be uncomfortable but is usually not painful. Your child may want to wear sunglasses or a peaked cap both inside and outside to protect the eyes from bright lights.
Who ocular albinism affects
OA is an X-linked disorder, which means it affects mainly boys. Boys with ocular albinism have an alteration in their only copy of the GPR143 gene. Genes are instructions for how the body develops or functions. Girls can be carriers of ocular albinism. Carriers are typically unaffected by ocular albinism, although some may have mild iris transillumination, which can be detected on an eye exam. Rarely, girls can develop symptoms of ocular albinism, although typically the symptoms are milder than those found in boys.
In contrast, oculocutaneous albinism (OCA) is most commonly inherited in an autosomal recessive manner. In autosomal recessive conditions, there are two copies of the gene, and both copies are not working. Girls and boys are equally affected. Carriers of OCA have one working copy and one non-working copy of the gene. Carriers can be girls or boys and are typically unaffected. There are several genes that can be associated with OCA; the most common are the TYR gene and the OCA2 gene.
Vision care for children with albinism
Your child with albinism should visit the eye doctor at least once per year to have their eyes tested.
Ask your eye doctor about your child's visual acuity (VA) before they start kindergarten. If your child has poor visual acuity (20/70 or worse), they may need vision aids for school.
Your child will probably sit very close to the television and will hold books very close to their face. This is normal for children with albinism and will not hurt their eyes or worsen their vision.
Devices and tips to help your child's vision
Your child may need assistive devices to see better. In Ontario, the Assistive Devices Program (ADP) may help you pay for devices to help your child's vision. Ask your eye doctor for a referral for a low-vision assessment. This type of service can show you different devices available to help your child.
These devices and tips may be especially helpful in school:
Glasses
- Eye glasses to correct near sightedness, farsightedness or astigmatism may help improve visual acuity in some children but will not give them 20/20 vision.
- Sunglasses will help protect the eyes from bright lights.
- Specially tinted lenses, such as corning lenses or contact lenses with a coloured part, can help children who are sensitive to light.
- Glasses with prisms can help to reduce nystagmus or correct strabismus.
Low-tech visual aids
- A magnifier can be used to enlarge an image or print. There are different types of magnifiers, such as dome, stand or hand-held magnifiers. These can help with tasks such as reading and looking at pictures and maps.
- A telescope can be used to help with distance vision. The most commonly used telescope is the monocular, which is a mini-telescope that can help to quickly view an object at a distance. For example, it can be used to find an object or read a sign. Most monoculars come on a lanyard for your child to wear around their neck.
- Closed circuit television (CCTV) is a machine that enlarges the print in books and photographs. It also adjusts the brightness or contrast of the image to help with glare. Your child should have one at home and one at school.
- White canes are usually not used by people with albinism for getting around. They can, however, be a useful safety device to alert others, especially drivers, that your child is visually impaired.
High tech
High tech vision aids can be useful for older students once they need to do a lot of reading.
- Software programs (for example, JAWS and ZOOMTEXT) can help increase the size of icons, cursor and fonts when using the computer.
- Computerized dictation programs.
- Video cameras that bring images closer and can attach to a laptop computer.
Vision itinerant teacher
If your child has low vision, make sure your child has an itinerant teacher. This is a special teacher who comes to your child's class to make sure they have what they need to do well in school, such as large print books and an arrangement to sit at the front of the classroom.
Driving
Some people with albinism can drive, but most cannot. Ask your child's eye doctor if your child has the minimum visual acuity needed to drive. The minimum visual acuity to get a driver's license in Ontario is at least 20/50 with both eyes (measured with glasses) and peripheral vision of at least 120 degrees.
Support
National Organization for Albinism and Hypopigmentation (NOAH) www.albinism.org