What is Lazy Eye?

Tricia Christensen
Tricia Christensen

Lazy eye, or amblyopia is a condition, where in most cases one eye does not see with the same visual acuity as the other eye, and poorly transmits visual information to the brain. If you cover the healthy eye, people with amblyopia will have a difficult time making out things, or may see very little at all. Sometimes cases are very minor and aren’t significantly noticed without performing a test where one eye is covered. The healthy eye may compensate for the lazy one, and cause very few changes to actual vision. In more severe case, depth perception is significantly affected.

An eye patch may be worn over an individual's dominant eye to correct refractive lazy eye.
An eye patch may be worn over an individual's dominant eye to correct refractive lazy eye.

There are three main types of lazy eye: strabismic, refractive or anisometropic, and form deprivation and occlusion. Strabismus is not amblyopia, but amblyopia may be caused by an eye that is strabismic, having a different focus point from the healthy eye. The eye without strabismus tends to take over and be dominant. Treatment of strabismus of any type is important so that both eyes are able to transmit visual images accurately.

Glasses may be worn to correct refractive lazy eye.
Glasses may be worn to correct refractive lazy eye.

If you have refractive lazy eye, your eyes send images to your brain at different speeds. The faster eye creates a much more accurate picture and begins to be favored. This form is corrected by glasses, and sometimes by using an eye patch over the dominant eye to help the mind readjust to relying on both eyes for sight.

Children under 5 usually have the best results for correcting lazy eye.
Children under 5 usually have the best results for correcting lazy eye.

If a single eye forms cataracts or has been injured to the point where seeing is affected, sometimes occurring in forceps delivery of infants, this is called form-deprivation or occlusion amblyopia. When possible, injury to the eye or cataracts are cleared to avoid permanent obstruction of vision in the affected lazy eye.

Strabismus can make the eyes appear crossed or "lazy."
Strabismus can make the eyes appear crossed or "lazy."

When the condition occurs in childhood, which is most common except for the development of cataracts or sustained eye injury, emphasis is on correcting any conditions creating poor eyesight, using glasses, visual exercises, and blocking the dominant eye. Lazy eye is best treated as soon as possible, with children under 5 usually having the best results for complete correction. Treatment later in life can be much more complicated since the condition is a brain disorder rather than a muscular one. Long dependence on a dominant eye creates greater difficulty in addressing the problem.

Still, many children who are treated after the age of 5 have a good chance of improving their vision. Even if vision is not completely normal, treatment will result in better vision than if treatment is not sought.

People who detect vision changes and disturbances should consult an ophthalmologist as soon as possible.
People who detect vision changes and disturbances should consult an ophthalmologist as soon as possible.
Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent wiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

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Discussion Comments


I'm 16 years old and have been wearing glasses since I was 3 years old. It was at kindergarten when people started noticing something was wrong, more to the end of the day when it was story time, the teachers noticed that my right eye would slowly start drifting in. They told my parents and I ended up with glasses, but because I was so young I have no idea what's actually wrong with my eyes. I know that the strength of my glasses is +4, however I don't understand this, because if I take off my glasses then I can see perfectly, up close and far away, but after a while I start getting the most painful headaches and my right eye starts drifting in and I start seeing double.

The farther apart the identical images are, the more my eye goes in. If I'm tired, then this is worse. With my glasses on I am perfectly fine, however if I am really tired, then my glasses make absolutely no difference whatsoever.

With or without glasses, I can also force my eye to go in for as long as I can, but this hurts more the longer I do it. Does anyone have a clue what could be wrong? -cmj


I'm 38 years old. When I was in the military I started to have an issue with my sight. At time I would have split vision. When this happened it felt like my eyes crossed and it appeared as though I was looking through a piece of glass that was cracked horizontally. This made it seem like the left side was slightly higher than the right side.

This was not constant but would happen, then go away after a few minutes. The longest period my vision was like this was about five minutes.

This has occurred a few times since then for very brief episodes. In the past year it has been happening more often. Now it causes very bad headaches. It is almost like both eyes are trying to work independently.

When I went to the doctor, he said it is most likely a muscle issue, but since it would come and go they could not diagnose it. The VA recently sent me to an eye doctor and he said my vision was excellent. I explained to him what was happening and he said it sounded like a muscle issue.

Has anyone heard of anything like this? Does anyone have an idea of what might be causing this?


forgot to add-there is definitely a difference in my vision, somethings appear higher/lower than they actually are depending on what eye i'm using.


i noticed about two years ago that my left eye is almost always around a few millimeters above my right eye (on one occasion, my left eye was half under the lid of my fully opened eye) a friend noticed in a few pictures as well and asked me if i had a lazy eye. i'm not sure that i do, because the only lazy eyes i've heard about the eye turns in, it doesn't "float" up, but i just wanted to check and see.


i never thought that i had lazy eye till now because my eye veers inward when im tired and i can always tell if i put my hands on my eyelids and close my eyes!



those sound like good ideas, but i'd definitely consult an ophthalmologist for a proper diagnosis and plan of action to treat your eye. as a child, my husband had a lazy eye, and had to have therapy and patching of the good eye to strengthen the weaker one. for the most part, it's fixed, but he spent years wearing glasses. now, when he's tired, the weak eye will sometimes pull in. he was told that if he hadn't gotten treatment when he did, he could've lost sight to his weak eye permanently--the brain finally just shuts it off.


I'm 17 and have had a lazy eye for all my life, I've never noticed it much until now, when I look in the mirror my left eye veers slightly inwards, it gets worse the more tired my eyes are, which is embarrassing at work when people look behind them thinking i'm addressing someone else when I say 'can I help you' :( .

As this article suggest it seems to be getting worse with age, my brains kind of sayin "right, that's your good eye, use it!" and completely blanks the left eye. it's to the point where I physically don't know how to use both eyes at the same time, seriously! However, I recently bought some coloured contact lenses, and put only one in, my good eye. I found that because i'd very slightly impaired my vision to the good eye, my left eye became much more active. I definitely think exercising the lazy eye is a sure-fire way to get it active and 'in-tune' with your brain again. I'm going to invest in that Nintendo DS game 'Sight Training', I think if I practice covering my good eye and just use my left to train with, i'll eventually be able to take the patch off and use both eyes at the same time. It's a theory in progress though, and it might take a while to get used to the function of using both eyes at the same time. I seriously don't want to end up looking like one of those people who's eye doesn't move at all, just sits there looking off into a different direction.


I am now 29 years old. I found my lazy eye problem when i was 8 having vision tests in school. But i paid no attention to it because i didn't think it would affect my life. I was astonished at the age of 27 when noted that my unhealthy eye-ball would shrink till it recognizes nothing. Is it true? Is it helpful if i have constant visual exercises or block the health eye using the unhealthy one alone?

I am so worried about it, could anyone here help me with it?

Thanks a lot.

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