Albinism is a genetic defect which affects the production of melanin. Melanin is the natural substance in the body that provides color to an individual’s skin, the iris of the eye and hair.
Albinism can cause problems like reduced visual acuity and stereoscopic vision (depth perception). It can also cause strabismus (crossed eyes) and nystagmus (involuntary movement of the eyes). These problems interfere with daily activities like reading, sports, driving and so forth.
Nettleship-Falls type is the most popular type of ocular albinism. The other types of ocular albinism are quite rare. In ocular albinism, the vision loss is permanent. However, it does not worsen with time.
Individuals with albinism can have normal to severe vision impairment. Those with the least pigmentation have the poorest vision.
- Oculocutaneous albinism (OCA) which causes a decrease in pigmentation of the skin, eyes and hair. It is more common.
- Ocular albinism (OA) which mostly affects the eyes. Usually, the hair and skin have a normal or almost normal color. OA is less common.
Genetic subtypes include:
- Tyrosinase-positive (albinism is mild to moderate)
- Tyrosinase-negative (albinism is severe)
Causes and Risk Factors
Genetic mutations passed from parent to child are responsible for albinism. The mutation disrupts production of melanin. Melanin is the pigment responsible for protecting the skin from Ultraviolet (UV) rays. It is also fundamental to the development of the eyes.
Lack of melanin means the retina and the iris will not develop as they should. The retina is the tissue that is sensitive to light and is located at the back of the eye. The optic nerve helps to relay images to the brain.
Albinism occurs among all ethnic groups worldwide. The condition affects one in 17, 000 people. Most types of OCA are recessive. Recessive means that both parents must have the gene which leads to a child being born with albinism. Here, both parents could possess normal melanin yet still have the gene. OA is X chromosome-linked. This means that OA is passed from mother to son.
Signs & Symptoms
Individuals with albinism have white skin, white hair and blue or pink eyes. However, not everyone with albinism will lack color on their skin or hair. An eye problem, however, is the first indication of albinism. There are also many eye problems associated with albinism. Some of the symptoms include:
- Nystagmus (uncontrollable rapid eye movements)
- Abnormal head position - To optimize vision, an individual may adopt a preferred head position
- Strabismus (eyes that are not aligned)
- Photophobia (light sensitivity)
- Refractive errors like astigmatism, nearsightedness, farsightedness.
- Monocular vision (vision in one eye)
- Abnormal development of the retina or foveal hypoplasia - When the retina fails to develop normally during infancy and before birth.
- Misrouting of the optic nerve - Failure of the optic nerve signals from the retina to follow the usual nerve routes
- Problem with the iris - Inadequate pigmentation to screen out unwanted light entering the eye
- Legal blindness (vision measures less than 20/200) or complete blindness
The eye professional will conduct a thorough examination. He/she will look for signs of photophobia, strabismus and nystagmus. The professional will also check to see that the retina has developed as it is supposed to. He/she will carry out an electroretinogram. An electroretinogram can reveal visual problems associated with albinism. If the diagnosis is not conclusive, a visual-evoked potentials test is necessary.
Genetic testing can also be done. It is the most accurate way to determine albinism.
Treatment of albinism is aimed at treatment and management of the conditions associated with albinism.
Albinism is not treatable. However, a proper ophthalmic and dermatologic management of albinism will help improve visual outcomes. The conditions related to albinism can be treated. For example, glasses are used to treat strabismus. Glasses improve vision and reduce instances of photophobia. Contact lenses can help where glasses have failed to correct vision.
The use of optical aids varies from individual to individual. Low vision aids like hand-held magnifiers can help children. Older children and adults can benefit from glasses that have small telescopes attached to the lenses. These glasses are useful for both short and far distances. Bifocals with strong reading lens may help some children.
There should be an emphasis to emotional, social and psychological support. People with albinism may experience low self-esteem. Parents and educators need to be sensitive to the needs of individuals with albinism. They should offer counseling and make certain adjustments to accommodate individuals with albinism. People with albinism can also participate in peer support groups. The support groups will help them feel less isolated, learn to be positive-minded and gather valuable resource information.
Surgery for strabismus can help to improve a patient’s field of vision. It may improve self-image and appearance. Abnormal head postures and nystagmus can also be improved with surgery.
People with albinism must protect themselves against the sun. They must deliberately prevent sunburn and decrease the risk of skin cancer by:
- Avoiding direct sunlight
- Protecting against UV rays using glasses
- Wearing clothes already sun-protected with a rated ultraviolet protection factor (UPF)
- Ensuring that they apply sunscreen to block UVA and UVB light
Albinism is a lifelong condition that has no cure. It does not get worse with time. This means that individuals will have to manage the related conditions associated with albinism.
Though very rare, patients with albinism may develop two systemic conditions. One is Hermansky-Pudlak Syndrome (HPS). HPS is associated with lung, bowel disease, unusual bruising and bleeding problems. There is also Chédiak-Higashi syndrome which affects numerous systems of the body. An individual with this syndrome is prone to infections, an enlarged liver and anemia.