Vision

Understanding Ocular Albinism

William was diagnosed with Ocular Albinism and Nystagmus on August 20, 2009. Jackson was diagnosed on November 30, 2010  Here is a FAQ that we have put together to answer some of the basic questions about it.

What is William’s diagnosis?
After an initial visit with a pediatric ophthalmologist, William has been diagnosed with Ocular Albinism and Nystagmus. The diagnosis was confirmed by Dr. Avery Weiss at Seattle Children’s Hospital.

What is Ocular Albinism and Nystagmus?
Ocular Albinism (OA) is a rare disease (1 out of 17,000) in which a lack of pigmentation in the eye results in varying degrees of vision loss, diminished visual acuity and light sensitivity.

A condition often associated with OA, Nystagmus is an irregular, involuntary eye movement that may be side-to-side, up and down or rotary. Although people with nystagmus do not sense that their eyes are moving, this disorder does make it more difficult to focus on visual details.  People with Nystagmus will often find a “null point” or the point where they are able to find their best area of focus by holding their head at a particular angle or direction. Will holds his head down and turned to the right. Nystagmus is NOT Strabismus (commonly referred to as a lazy eye or crossing of the eyes).

How are these conditions diagnosed?
William was examined (see below for details) after Nystagmus was observed at about 4 months of age. If OA is suspected, doctors look for decreased amount of pigment in the retina, foveal hypoplasia (poorly formed center of the macula) and trans-illumination defects of the iris (abnormal passage of light through a poorly pigmented iris). In addition to testing for OA, a standard vision test was administered and Will’s vision was determined to be below normal.

Jackson’s OA was confirmed with an OCT, Optical Coherence Tomography, test, which maps the retina. It is like an ultrasound for your eye.

How many doctors have we seen?
Will was initially diagnosed by a pediatric opothmologist at Virginia Mason, Dr. Janet Barrall. The diagnosis was confirmed by Dr. Avery Weiss, Division Chief of Opthamology at Seattle Children’s Hospital. Dr. Weiss diagnosed Jackson in November 30, 2010. We are continuing to see Dr. Weiss.

How are the boys vision now?
Will’s acuity is testing in the normal range, however his vision will stop getting better at some point. We will know what his vision is when he turns 3. Teller Acuity Cards are used to test his vision.

Jack’s vision is 20:25 in his right eye and 20:40 in his left. He is tested using the typical letter tests.

What parts of the eye are affected by Ocular Albism (see diagrams)?
Retina – the back of the eye, contains the cells that convert visual input into signals to send to the brain. A lack of pigment in these cells leads to a decreased ability to process visual input. In addition, the fovea at the center of the macula — the area of the retina responsible for our sharpest vision – is underdeveloped and lacking in pigment.

Optic Nerve – the connection from the eye to the brain. Between the eye and the brain, there is an area where the optic nerve splits into separate fibers which are routed to the brain. In normal-sighted people, most of the fibers stay on the same side of the brain while some cross to the opposite side. This helps with “binocular vision” (using both eyes) and, in turn, depth perception. In people with OA, too many fibers cross to the opposite side, giving the brain an abnormal signal leading to difficulty with depth perception. Melanin provides the signal that indicates which fibers should cross over and which should not. In OA, there is a lack of melanin resulting in an improper crossing of these fibers.

Iris – the colored part of the eye. An insufficient amount of pigment in the iris results in a decreased ability to filter light and leads to trans-illumination defects (light reflecting back through a poorly pigmented iris). This often causes sensitivity to light and may require use of sunglasses.

Is Nystagmus or OA correctable? Will these conditions improve or go away over time?
Currently, there are no cures for the vision loss and impairment related to OA.

Nystagmus can diminish over time but rarely resolves completely. There are some procedures that attempt to dampen the eye movement but we aren’t sure about the effectiveness of these procedures.

Will eyeglasses correct the problem?
No. Eyeglasses will only correct nearsightedness, far-sightedness and/or astigmatism (defects of the lens). People with OA may wear glasses to help correct standard vision defects but glasses will not correct the vision loss and diminished acuity caused by OA.

Can these conditions get worse over time?
OA is a non-degenerative retinal condition, which means it does not worsen with time (other than the “normal” changes that occur with age and are correctable with glasses). In fact, with some forms of albinism, vision may actually improve slightly throughout childhood.

What can you do about this? Are there steps you can take now to help improve his eyesight?
No, we just have to let their eyes develop.

What is his vision like now and what will it be like in the future?
It is impossible to tell because William can’t tell us. One description we found was “not as blurry as it would be for nearsighted people, but lacking in clarity and detail, like a photograph with low resolution.” Most people with OA are able to distinguish colors.

Some people with OA are legally blind, while others have mild impairment. Vision may vary from 20/40 to 20/400. Legally blind is defined as vision that is not correctable to better than 20/200. However, this is quite different from total blindness. Most who are legally blind are able to read without using Braille. We will not know the extent of his vision impairment until he is 2-3 years old when he is able to communicate what he can see.

What about school?
Most children with OA function well in a mainstream classroom, with special accommodations as needed depending on the severity of their vision impairment.

Can people with OA read books?
Yes but some accommodations will likely be necessary. These may include large print books, a closed circuit TV, magnifiers, audio books, high contrast materials and other aids. Although Braille is typically not necessary for people with OA, some may choose to learn it in order to give their eyes a rest.

Will they be able to play sports, drive a car and do other things that require hand-eye coordination?
Maybe or maybe not. His ability to do these and other activities will largely depend on the severity of his condition, the full extent of which will not be known for several years.

How do you get Ocular and other forms of Albinism?
Most forms are recessive, which means that a child inherits one abnormal gene from each parent. Most children with albinism are born to parents with normal pigmentation. These parents — about one in every 75 people — are carriers. A carrier is someone who has one abnormal gene and one that functions normally. Because the functional gene overrides the abnormal one, these people do not have albinism themselves. However, they are still able to pass the abnormal gene on to their child. For parents that both carry the gene, there is a 1 in 4 chance of a child having the condition.

What is the difference between Ocular Albinism and Oculocutaneous Albinism?
Ocular Albinism only affects the eyes and is most commonly found in boys. This is what William has. Oculocutaneous Albinism affects eye, hair and skin and includes different genetic subtypes.

Will he be ok?
Absolutely. There are many services and support programs available to children with this condition. Like we did with both Jack and William’s feeding issues, we are being realistic about the diagnosis, educating ourselves and tackling this head on and we expect that he will thrive. It is our goal to give them every possibility in life and for this to not hold them back. We will work to provide them with as many opportunities as possible.

 

 

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