About Ocular Albinism
There are several different definitions of Ocular Albinism. Here are just a few.
According to the National Eye Institute:
Ocular Albinism Type 1 (OA1) is an inherited, X-linked disorder wherein skin and eye color are normal, but the retina lacks pigment. Individuals with OA1 show quite poor visual acuity and other visual abnormalities. The pathology of OA1 includes disturbances in retinal ganglion cell (RGC) axon development and guidance, and other developmental abnormalities such as myopia.
According to NOAH:
Ocular albinism in an inherited condition in which the eyes lack melanin pigment, while the skin and hair show normal or near-normal coloration.
The lack of pigment in the eyes causes various vision problems:
The reduced visual acuity may result in difficulty in school, such as inability to read what is written on a chalkboard except when very close, and difficulty with ball sports. It may also result in inability to drive.
With ocular albinism, the color of the iris of the eye may vary from blue to green or even brown, and sometimes darkens with age. However, when an eye doctor examines the eye by shining a light from the side of the eye, the light shines back through the iris since very little pigment is present. There may be areas of the iris which have very little pigment.
The main problem with the eye in ocular albinism is in the fovea, small area of the retina which affords acute vision. With ocular albinism, the fovea does not develop completely, presumably because melanin pigment is needed for the growth processes that normally occur before birth. Therefore the eye cannot process sharp light images. Because the fovea does not develop well, it is difficult to correct vision completely with glasses.
Another defect in ocular albinism is that nerves from the back of the eye to the brain do not follow the usually pattern of routing. From the normal eye, nerve fibers go to both sides of the brain, that is, the same side as the eye and the side opposite from the eye. From the eye with ocular albinism, more of the nerve fibers cross from the eye to the opposite side of the brain. A test called a visually evoked potential, which is performed like an EEG or brain wave test, can show this difference. These eye problems are very similar to those of oculocutaneous albinism (albinism which involves the skin and hair as well as the eye).
According to The VOC Foundation:
Human albinism can be divided broadly into two types, "Oculocutaneous Albinism (OCA)" and "Ocular Albinism (OA)". These terms were devised in the late 1940s, when medical science was less sophisticated than it is now. The terminology sounds simple, but in reality is probably incorrect, since all forms of albinism have relative deficiencies of pigment in the hair, skin, and eyes.
Historically, "Ocular Albinism" is an inherited disorder in which the eyes are deficient in the amount of melanin and pigment, while the skin and hair "appear" normal or near normal in coloration.