The Dr. Bill Takeshita Foundation

Last Modified: Sat, 18 Aug 2007

View other Common Causes of Vision Impairment

Albinism is a congenital condition that affects the pigmentation and color of the eyes and may also affect the skin and hair. Most patients with albinism have a very high degree of vision and are some of the best candidates for low vision care. The main visual consequences of albinism are photophobia (sensitivity to bright light and glare), blurred sight, and nystagmus (uncontrollable shaking of the eyes). There is no surgical or medical treatment to correct albinism but fortunately it is a stable condition that does not lead to total blindness. Corrective spectacles, filters, and low vision aids enhance the vision of those with albinism to perform reading, writing, and many hobbies visually. In fact, many patients with albinism have received their driver’s licenses after being fit with specialized low vision spectacles.

Albinism is a genetic condition where the production and distribution of pigment are altered by the defective gene. One such gene directs the production of an amino acid called tyrosine, which is involved in the production of melanin, the pigment that provides color to cells called melanosomes. When the genetic defect interferes with the production of tyrosine, pigment is not produced and the eyes, hair, and skin do not have any color. This form of albinism is called tyrosinase negative albinism. In contrast, tyrosinase positive albinism is the form where pigment is produced but the gene that directs the distribution of pigment is defective. Consequently, the hair, skin, and eyes have minimal pigment. In both tyrosinase positive and negative albinism, the lack of normal pigmentation affects the eyes, hair, and skin and is thus classified as oculocutaneous albinism. Oculocutaneous albinism affects both males and females equally and is transmitted in a recessive manner, suggesting that both parents must be carriers of the defective gene in order for their children to have albinism. If both parents are carriers of the defective gene, there is a one in four chance that their children will have oculocutaneous albinism.

Albinism that only affects the eyes is called ocular albinism. This is also a genetic condition but it primarily affects males. The defective gene responsible for ocular albinism is located on the X chromosome and is passed in a recessive manner from the maternal grandfather to his grandson. The defective gene alters the pigment cells of the eyes but does not affect the hair or skin. Thus, ocular albinism is often more difficult to diagnose in newborn males and is often misdiagnosed as congenital nystagmus.

In albinism, the central portion of the retina called the macula is not fully developed. This is called macular hypoplasia. The macula contains millions of cone cells that are responsible for detailed sight. Because the macula is not fully developed, patients with albinism have blurred distance and near sight. Depending on the severity of the macular hypoplasia, the visual acuity may range from 20/40 (able to read a 1 inch letter from 20 feet) to 20/400 (able to read a 7 inch letter from 20 feet). Functionally, the blurred sight can force patients with albinism to bring objects close to their eyes to identify the details, have difficulty identifying faces of people from beyond twenty feet, and may interfere with their ability to read quickly.

The lack of pigment to the eyes causes sensitivity to bright light and glare (photophobia). The severity of photophobia is dependent on the amount of pigment in the eyes. Many patients are able to adapt to normal lighting conditions while others may be non-functional during the day but very functional at night. In addition to being sensitive to glare and bright light, patients with albinism may require additional time to adjust to different lighting conditions.

Most people with albinism have nystagmus, the uncontrollable shaking of the eyes. This condition generally does not cause them to see the world as shaking from side to side. However, many patients with albinism will turn or tilt their head to position their eyes in a manner that reduces the nystagmus. Eye muscle surgery, rigid contact lenses, and eye exercises are sometimes recommended to attempt to reduce the nystagmus but it is rare for nystagmus to be completely eliminated.

Refractive errors such as farsightedness (hyperopia), nearsightedness (myopia), and astigmatism are more common among patients with albinism. In some cases, glasses will significantly improve the clarity of sight. However, in other cases glasses are not helpful. This is dependent on the level of macular hypoplasia. If the macula is severely underdeveloped, glasses will not improve sight regardless of the degree of refractive error. Conversely, when the macula has a higher number of cone cells, glasses may improve the clarity of sight significantly.

Patients with albinism tend to have many visual strengths. They generally have excellent color vision, peripheral vision and night vision. Thus, they are often able to use their vision more effectively during the evening or on overcast days. Low vision aids can simulate these conditions and patients with albinism generally access their academic materials visually. In addition, some patients are able to receive restricted drivers licenses when they use specialized low vision aids to improve their sight and reduce their problems with glare.

Recommendations

• A consultation by a low vision specialist and low vision aids? can provide specific recommendations regarding devices that will improve visual function.
• Vision stimulation will provide infants with the best opportunity to maximally develop their vision. See Developing Your Child’s Vision? for more information on specific recommendations.
• Children and adults should wear tinted lenses to protect the eyes from the ultra-violet rays of the sun. Transitions photochromic lenses are very helpful for children who may have difficulty changing from indoor to outdoor glasses. The use of a hat with a dark under-surface brim is also very helpful to reduce eye discomfort from glare and bright light.
• For more information, please see Low Vision Rehabilitation

Recommendations for students

• Position students as close as possible to the chalkboard or dry erase board. Try to use bold architecture chalk or bold dry erase markers. Letters and words written 4 inches in height should be readable for students with 20/200 acuity when they sit 10 feet from the board. Colored chalk and dry erase markers are not recommended because they do not provide sufficient contrast for many students with low vision.
• Try to position students such that their backs face windows and doors.
• Students will benefit from having copies of overhead transparencies, PowerPoint presentations, and other educational material written on the board. Focusing on the chalkboard and copying the material on paper is one of the more challenging tasks for students with low vision to perform quickly.
• When making PowerPoint presentations, the use of a dark background with white or yellow text will provide the best contrast for easier reading. The use of Arial or Tahoma fonts is recommended.
• Some students may prefer to use bold felt pens along with tinted paper with bold lines to increase contrast for writing. Gel pens with 1.0 mm. Thickness are also very helpful.
• Sports such as baseball, tennis, and racquetball may be difficult sports for students to play due to their reduced clarity of sight. Soccer, basketball, swimming, and track may be alternative sports that may be more suitable for students with low vision.

Recommendations for teenagers and adults

• Computer and assistive technology can be extremely valuable for many students when working on the computer and reading for long periods of time. Electronic video magnifiers, software magnification programs, screen reading software, and scanning software can help students and adults to read, write, and access information more efficiently.
• Computer users will benefit from using a larger computer monitor, large print keyboards, and computer monitor arms to reduce neck and back strain. The background and text colors should be customized to maximize vision and eye comfort. For specific instructions on how to modify your Windows XP computer, see Solutions to Help You Use Your Computer?.

Specific recommendations for patients with albinism:

• Reduce the ambient illumination in the room. Use desk lamps such as the OTT full spectrum desk lamp or an incandescent desk lamp with a 45-watt Reveal bulb. For more details, see Lighting and Vision.
• At work, turn off the overhead lights of the office and use a desk lamp.
• Bioptic telescopic glasses are extremely helpful to improve distance sight. In many states, bioptic glasses can be used for driving. For specific details, contact the Department of Motor Vehicles for your state.
• Specialized filters and contact lenses can reduce the severe problems with glare and bright light. Transitions photochromic lenses, NoIR filters, and mirrored lenses can simulate night conditions and improve visual function significantly.
• High power reading glasses, high power bifocal spectacles, and pocket magnifiers allow users to read small print, read books, and use the computer. The use of blue filtering tints is often very helpful for use indoors.
• Hand held telescopes, hand magnifiers, and pocket magnifiers are also helpful for reading small print for short periods of time.. Dome magnifiers are helpful for young readers who are beginning to read books.