Strabismus is the very general term used to describe conditions in which a person’s eyes are not aligned properly. There are three very general situations in which this type of condition can develop:

Let’s talk first about the general category of the infant or child whose eyes are found to be out of alignment. Though the actual movement of the eyes is controlled by muscles in the eye socket, much of the input as to how the eyes move depends on what the eyes are seeing and how the brain interprets that information. In general, most children with strabismus fall into one of the following categories:

• Although the eyes are not properly aligned, they appear very healthy on examination and there may be no significant need for glasses. The belief in this situation is that these children do not develop double vision when one eye turns in or out. Thus they do not have the strong drive to keep the eyes straight. Put another way, if you push on one of your eyes so that it is turned and look at a picture, you will most likely see two of the same picture. That is a very disturbing visual sensation. Children whose visual systems are unable to develop double vision are more likely to develop strabismus. There is often a family history of strabismus in these situations.
• The eyes appear healthy, but examination reveals that one or both eyes is very far- or near-sighted or has significant astigmatism. In these cases, glasses may play a role in treatment.
• Examination reveals that there may be a condition causing one or both eyes not to see well, such as cataract, or problems with other parts of the eye (i.e. the retina or optic nerve.) Although this general category is the least common of the three, it is extremely important to perform a thorough examination to make sure the eyes are healthy.

With respect to individuals who develop strabismus after early childhood, the cause of the problem is almost always linked to a condition which affects the function of one or several of the eye muscles. Diagnosis of the cause relies upon a thorough eye examination as well as a complete medical history and often other testing (e.g. blood tests, scans).

For children found to have strabismus, it is usually parents, family friends, or pediatrician who first notice that a child’s eyes do not appear straight. Occasionally, the red reflection often seen in the pupils of eyes in photographs may appear asymmetrical, which can be a sign of misalignment. Vision testing in school can also help to diagnosis children with strabismus. In families with a history of strabismus or "lazy eye," attention should be paid to signs of strabismus so treatment can be rendered as soon as possible.

Adults who develop strabismus almost always discover the condition themselves as they almost always develop the very bothersome symptom of double vision.

It is not uncommon to hear a parent say that they were told that there child would "grow out of it." Unfortunately, this fallacy can result in vision impairment that could have been prevented had it been diagnosed and treated properly. The truth is that infants and children noted to have possible strabismus should be evaluated soon after the problem is suspected. There are two important reasons for this:

• If a child has an eye which is turned, treatment (e.g. glasses, patching, others) can be initiated right away. The earlier an amblyopic eye (i.e. the eye which is not seeing well due to being turned) is treated, the more likely good vision will be restored.

• Once #1 is accomplished, to identify the pattern of strabismus and its cause. Sometimes glasses will be used if there is a significant far- or nearsightedness or a large difference between the eyes. Bifocals may be needed in some instances.

• The next goal of treatment is ensuring the best possible vision in each eye. This often involves both glasses and patching (i.e. covering the better eye to force the weaker eye to be used.)