Anisometropia – Is a condition where the refractive power for both two eyes is unequal. Both eyes’ conditions don’t have to match; one can be myopic, or nearsighted and the other eye can be hyperopic, or farsighted.
Anisometropia is a condition the medical society has a great with for newborns and children early in life; this is because the condition can lead to amblyopia. If a large amount of anisometropia is present the brain is not able to figure out the difference in the images being viewed by two eyes. The brain will resolve to ignoring what one eye sees and eventually block it out all together.
There are four parts of anisometropia all coming from Greek:
An - not
iso - equal
metr - measure
opia - vision
This literally means, the measure of vision (refractive power) in both eyes, is not equal. Isometropia is the opposite; both eyes having the same refractive power.
Anisometropia – Unequal Vision
Being that anisometropia means the refractive power is different in each eye, it can mean being farsighted in the right eye and nearsighted in the left; or vise versa. It is common for people with this condition to also have aniseikonia, which causes each eye of a person to see the same objects in different sizes. LASIK surgery can be performed to correct both conditions.
Anisometropia can be mild needing only a small difference in the Rx for each eye, or be extremely different with one ye being extremely hyperopic and the other being extremely myopic.
Glasses can hold a strong plus Rx for the hyperopic eye and a strong minus for the myopic eye to accommodate the vision. However, if there is an extreme difference it can cause a problem with double vision occurring. Glasses tend to not work as well as contact lenses for this condition, but not all people can tolerate contacts so they cannot wear them. For small children glasses or contact lenses are not the answer, they cannot always wear either. LASIK surgery can correct the refractive power in each eye by making it equal.
When no treatment is given for anisometropia, the brain will choose which one of the two objects is best; the stronger eye (where the vision is better) will then become the main or dominant eye. The non-dominant eye may become worse over time.
Refractive surgery can also cause anisometropia requiring additional surgery to correct.
Is a condition common for people inflicted with anisometropia is aniseikonia, however this is something a person with matching Rx’s in each eye can have also. Eyes that are two different sizes, having different conditions of the retina and requiring different treatments, a lens being replaced, and other surgeries can all result in aniseikonia. This condition is a common experience when refractive surgery is done on just one eye. This condition can be quite unpleasant even debilitating for some people if long lasting.
- Difficulty reading
- Light sensitivity
- Eye strain
- Double vision
- Impaired depth perception