Homepage

About Us

About Aniridia

Living with Aniridia

The Aniridia Directory

Join Us

Contact Us

Make a Donation

Web www.aniridia.org

Also known As

lazy eye

What is Amblopyia?

Amblopyia is a condition in which the vision in one eye is weaker than in the other. This causes a large difference in the visual information being received by the brain, so the brain ignores the information from the weaker eye and the stronger eye becomes the dominant eye. This occurs in childhood when vision is still developing.

Why does this affect people with aniridia?

While Aniridia is a bilateral condition, i.e. both eyes are affected, usually one eye is more affected than the other.

Fovea hypoplasia may affect one eye more than the other, causing a difference in visual acuity between the two eyes.

The cataract in one eye maybe more developed than in the cataract in other, causing information in the weaker eye to be more blurred than in the dominant eye.

Glaucoma maybe affect one eye more than the other, which has lead to a decrease of vision in the weaker eye.

Ptosis (droopy eyelids) may affect one eye more than the other, therefore blocking the vision in the weaker eye.

The child may have strabismus which means their eye is not aligned correctly.

A reason, which is not related to aniridia, is that they may have a more acute refractive error in the weaker eye that needs correction.

What is the Affect of Amblopyia

Each eye collects 2D information, i.e. the information is flat like a picture. The information from both eyes is collected at the back of the brain and the two pictures are joined. Because each eye has a slightly different view, when the information is put together what we see appears to be 3D.

When the visual information received at the back of the brain from each eye is very different, the brain cannot fit the two together, the brain ignores the information with less detail, i.e. the information from the weaker eye. Using only one eye the brain only sees the world in 2D, therefore, people with amblopyia have no 3D vision.

3D vision is helpful in fulfilling a number of day-to-day tasks like...

Throwing, catching or hitting a ball
Driving and parking a car
Planning and building a three-dimensional object
Threading a needle and sewing
Reaching out to shake someone's hand
Pouring into a container
Stepping off a curb or step

This is because 3D vision helps us judge depth, distance, space and the accurate position of an object. However, people without 3D vision can still do many of these things, they find that good contrast, shadows, and markings indicating, say the edge of a step, help them judge where things are and navigate around their environment. These methods are not always accurate especially when the design of surroundings does not consider those who have difficulty with 3D vision. They may need time to familiarise themself with their surroundings and practice certain activities, i.e. catching, hitting and pouring.

What treatment is available?

To find out the cause of the amblyopia, the ophthalmologist will use cycloplegic refraction. Cycloplegic is a type of eyedrop used to numb the muscles in the eye that enable the eye focus. These are usually used on children so that an ophthalmogist, or optometrist can accurately determine the refractive error in each eye.

Then treatment must focus upon the cause of the difference in visual information. For example, if it is cataracts, they may be removed and replaced with artificial lenses, or if it is a refractive error, the person will need to correct it with glasses or contact lenses. If the child also has Strabismus, muscle surgery may be used to correctly align the eyes.

After treating the initial cause, patching or eye drops may be used to block the vision in the dominant eye and encourage the brain to use the information from the weaker eye.

Detection and correction between ages 6 mos. to 2 years, offers the best chance, but from then on success decreases with age. Treatment can be fairly successful between the ages of 2 and 6. After the age of six, true amblyopia can not be cured, but treatment should attempted as it can be successful in improving visual acuity. At this stage treatment is not dependent on age and requires a lot more effort.

In aniridia, 3D vision may not be obtained if the persons visual acuity is very low and the long term success of treatment cannot be guaranteed as many of the aniridia associated conditions appear at different stages of life and invasive treatment may be put off until absolutely necessary to avoid the high risks of further complications. For specific information related to your own situation please talk to your ophthalmologist.