Friday, November 11, 2011

What is Aniridia?

For more information on Aniridia, please check out the following link:
the facts provided below have been taken from this site.

Aniridia FAQs

  1. What is Aniridia?
    Simply put, aniridia is a genetic condition where there is little or no iris.
  2. Are people with aniridia blind?
    No. Their vision may vary from 20/40 to 20/400. People with aniridia may be “legally blind” which is defined as vision that is not correctable to better than 20/200. However, this is quite different from total blindness. With 20/200 vision, one can still see colors, lights and the outline of large objects.
  3. What can aniridics see?
    It is difficult to say. Because the range of vision is different for each aniridic, there is not one good description to explain what all aniridics can see. All aniridics will have challenges with seeing detail, due to the underdeveloped retina (foveal hypoplasia). Most pediatric ophthalmologists will tell parents of an aniridic child “we will have to wait until he/she can tell us what he/she can see.” This can be very scary and frustrating. An aniridic child’s sight can develop and get better over time.
  4. Will their vision get worse over time?
    It can. The non-degenerative parts of this condition are the lack of iris (it will never grow) and the foveal hypoplasia (the underdeveloped retina). These conditions will not worsen with time (other than the “normal” changes that occur with age and are correctable with glasses). However, the impact of the secondary conditions such as glaucoma, corneal pannus and cataracts can worsen one’s sight.
  5. What causes the irregular eye movements?
    This is a condition called nystagmus. The involuntary eye movements may be from side-to-side, up and down or rotary. Nystagmus is present to varying degrees in people with aniridia and typically declines with age. It tends to increase when the person is upset, excited or tired.
  6. Does nystagmus affect vision?
    Although people with nystagmus are not aware that their eyes are moving, it does make it more difficult for them to focus clearly on details. In fact, they often will find a “null point” which is the point where their nystagmus is the least apparent (see below).
  7. What is the “null point”?
    People with aniridia have a poorly developed fovea. In normal-sighted people, the fovea is in the center of the macula and an image will land there when the person is looking straight ahead. Their fovea is where they focus for their best detail vision – such as seeing a freckle on a person’s face. Because a person with aniridia has an underdeveloped fovea, they must find their best area of focus which may be anywhere on their retina. Typically, they will move their head to the position necessary to focus on this spot, consequently slowing their nystagmus and allowing for their best vision. This is their null point.
  8. Is any of this correctable?
    With the technology that is currently available, there are many treatment options for the secondary eye complications. First, there are instruments to measure eye pressure to keep glaucoma under control. If glaucoma is diagnosed, there are eye drops and/or surgeries to correct it. Also, there are surgical remedies for the corneal pannus such as stem cell transplants. Additionally, there are iris implants available (in all colors) to help decrease the amount of light that flows into the eye. However, this is not yet FDA approved. Please see Treatments section of "What is Aniridia" Page for more details.
  9. How does someone get aniridia?
    Aniridia is a genetic condition caused by an anomaly in the 11p13 section of the PAX6 gene. The genetic problem can be sporadic (happens first time within either the egg or sperm) or familial (passed on from one parent). Unlike most genetic conditions, this is autosomal dominant, meaning it takes only one mutated gene to cause this condition. Aniridia is not contagious. There is a fifty percent chance of an aniridic passing it on to one’s offspring.
  10. How can two people without aniridia produce a child with aniridia?
    Both parents of an aniridic can be “normal,” having NO genetic mutation or deletion of the PAX 6 gene. If these two people have an aniridic child, the aniridia is called “sporadic,” The child obtained this genetic mutation or deletion from a spontaneous change in the egg or sperm. The condition existed BEFORE conception. So, there was NOTHING done during the pregnancy that caused this problem. If these two parents should have another child, the chance of aniridia occurring in the next pregnancy is the same chance as any one else in the general population – very slim.
  11. If an aniridic has a child, what are the chances of that newborn child having aniridia?
    Unlike most genetic conditions, aniridia is dominant. It only takes one parent to have the mutation or deletion to pass on this condition. Therefore, the chance of an aniridic man or aniridic woman having an aniridic child is fifty (50) percent. If an aniridic should have a child with aniridia, the condition is called “familial” aniridia, because it was passed on by an aniridic parent. Currently, there is the possibility of identifying the mutation or deletion in the PAX 6 gene and using egg or sperm sorting to try to stop the aniridia from being passed on. This technology is very new and not much is known about its success rate.
  12. How is aniridia diagnosed?
    Aniridia can be diagnosed by an experienced ophthalmologist with a simple eye exam. There are genetic tests available as well but they are not yet perfected. For more information on genetic testing, contact a qualified genetic counselor. Genetic counselors are generally affiliated with universities and/or children’s hospitals. Since aniridia is also associated with glaucoma, it is important that the ophthalmologist check an infant’s eye pressure.
  13. What is foveal hypoplasia?
    The fovea is the part of the retina, in the center of the macula where one would normally focus for the sharpest most detailed vision. In people with aniridia, this area is poorly formed or, in some cases, not present. This is known as foveal hypoplasia.
  14. Is aniridia associated with mental retardation?
    In most cases, aniridia is caused by a mutation in the PAX6 gene, and is not associated with mental retardation.  However, in about 30% of cases, sporadic (non-inherited) aniridia is caused by a missing, or deleted PAX6 gene, rather than a mutation.  In these cases, deletion of other genes in the same area results in WAGR syndrome (WAGR is an acronym for: Wilms tumor, Aniridia, Genitourinary abnormalities, and mental Retardation).  Although mental retardation is common in individuals with WAGR syndrome, neither mental retardation nor any of the other conditions is always present.  For this reason, genetic testing is recommended for all infants born with sporadic aniridia.  For more information on WAGR syndrome:
  15. Should aniridics have ultrasounds to test for Wilm’s tumors?
    Most pediatricians recommend that aniridic children with a deleted PAX 6 be tested for Wilm’s tumors every 3 months, as the possibility is high if there is a deletion. There is debate as to whether children with only a mutated PAX 6 gene undergo ultrasounds. Many pediatricians believe that this non-invasive ultrasound is a safeguard for catching tumors early. Early detection is KEY in fighting these cancerous tumors. Therefore, the consensus is that “it can’t hurt” to get the ultrasounds. As to how often, the safest procedure is to have the ultrasound every 3 months until the child is eight years of age, when the probability of the Wilm’s tumors decreases significantly. At that time, the monitoring is decreased to every 6 months or even annually. There has been a case of Wilm’s tumors being detected in a 24 year-old aniridic patient, so the annual monitoring is a good idea.
  16. Do people with aniridia have to go to special schools?
    No. Most children with aniridia function well in a mainstream classroom, with proper accommodations. Please see the Education Tool Box.
  17. Are there special services for children with aniridia?
    Yes. Please see the Education Tool Box for a more complete explanation of services, including Early Intervention offerings from birth.
  18. Can people with aniridia read books?
    Yes! Although Braille is typically not necessary for people with aniridia, a few may learn to use it in order to give their eyes a rest. Depending on the degree of visual impairment, other accommodations may be necessary. These include large print books, a CCTV, magnifiers, and high contrast materials. Please see the Education Tool Box for more information.
  19. Do people with aniridia spend a lot of time going to doctors?
    Yes! It is very important for aniridia patients to closely monitor each eye and to see the correct specialist for each problem (glaucoma ophthalmologists, cornea ophthalmologists, pediatric ophthalmologists, etc). For more information, please refer to the Medical Tool Box.
  20. How does the sun affect the eyes of people with aniridia?
    Most people with aniridia are sensitive to light. Imagine a “normal” person with their eyes dilated at an eye doctor appointment. This is how the eye of an aniridic is at all times. Therefore, it is very important for them to wear sunglasses: a) for comfort and b) to protect the retina. One of the purposes of the iris is to protect the retina from too much sun. The retina can be damaged from too much sun exposure if the aniridic does not wear sunglasses.
  21. Can people with aniridia go outside?
    Absolutely. With proper sunglasses, they can go anywhere, including the beach!
  22. Are there other medical problems associated with aniridia?
    Yes.  Recent research indicates that other medical problems may be associated with aniridia (all types).  These include: glucose intolerance, (thought to be a precursor to diabetes in some individuals)  central auditory processing disorder (difficulty with discriminating and interpreting sounds) decreased or absent sense of smell, and subtle abnormalities in the structure of the brain, such as decreased size or absence of the anterior commisure and/or the pineal gland.  When aniridia occurs as part of WAGR syndrome, there may be medical problems in addition to those listed above. More information on these can be found here:
  23. Can people with aniridia drive a car?
    Sometimes. The requirements vary by country and by state. They may be required to wear a bioptic device to drive. For details, please see
  24. How can I meet others with aniridia?
    You can start by contacting Wendy is a Board Member of The Vision for Tomorrow Foundation.  Her son has aniridia.

1 comment:

  1. What great posts these are! We're learning lots about your sweet lil gal :)