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"Can one eye be bigger than the other?"

ZocdocAnswersCan one eye be bigger than the other?


Is it possible for one eye to be bigger than the other? My infant son seems like he has a difference between his eyes, but maybe I'm imagining it. If there is a difference in eye size, will that cause vision problems for him later? Should we be acting on this right now?


Vision is a complex process which develops throughout one's infancy. I would recommend you discuss this with your child's doctor in order to make sure any problem is detected early. An examination is also important and should be done soon. To answer your question--yes, it is possible for one eye to be larger then the other. Different parts of the eye can give the appearance of inequality, but the most commonly noted difference is in the pupils (the colored portion of your eye). Inequality between the two pupils is known as aniscoria. This can be normal if the difference is < 0.5 mm. This is more prominent in lighter eye colors. The size of the pupils is controlled by the autonomic nerves. The autonomic nerves that control the eye size are distinct from the optic nerve of vision so normally vision is not immediately affected. Processes that effect the autonomic nerves include infections (known as Adie syndrome) or masses--in the brain or in the upper chest. Remember it can be normal, especially in a developing child. The other concern is that the eyes are not different in size, but appear different as they are oriented differently in the eye. This is known as strabismus. This is important to correct early as the brain develops based on the visual inputs--so the earlier it is treated the better for the long term vision. I would recommend you see your child's doctor soon. While likely normal, a thorough exam can be important to rule out serious problems.

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