Strabismus - "Eye Turn"
A strabismus is defined as a condition in which the eyes deviate (turn) when looking at the object of regard (i.e. person can not align both eyes simultaneously under normal conditions). One or both of the eyes may turn in, out, up or down. An eye turn may be constant (when the eye turns all of the time) or intermittent (turning only some of the time, such as, under stressful situations or when ill). Various names often refer to this condition: eye turns, crossed eyes, cross-eyed, wall-eyes, wandering eyes, deviating eye, etc. Strabismus is not the same condition as "lazy eye" (amblyopia).
It is estimated that up to 5 percent of the population has some type or degree of strabismus. Children with strabismus may initially have double vision. This occurs because the misalignment of the two eyes in relation to one another creates two distinct images, one for each eye. In an attempt to avoid double vision, the brain will eventually disregard one of the images and suppress one eye. Occassionally, the brain can learn to develop a new match with each eye so that fusion occurs even though the eyes are not aimed at the same spot. This is known as anomalous retinal correspondence. It occurs early in life and will almost never occur if the strabismus develops after childhood.
- Measurement & Classification
- Age Considerations
Eye doctors generally analyze and measure a strabismus with the patient looking at distance (20 feet or more), up close (around 16 inches), and in all directions of gaze (up, down, left, or right). Furthermore, strabismus is classified by the direction of the eye turn, the frequency of the eye turn (constant or intermittent strabismus), and on the size of the ocular deviation, with particular attention on whether the patient is suppressing one eye's image or not. If suppression is present, generally, the longer suppression has been in effect, the more difficult it will be for the patient to eliminate and re-establish normal binocular vision. Thus, early detection and treatment is very important in all cases of strabismus!
This is a very common question, and in fact, there is no age that shouldn't deserve a chance! Age should not be a deterrent, though treatment under age 6 (especially before 2) is ideal and allows better results than later treatment. After age 6, age is not as important.
Studies have shown that the best chance to regain maximal functionality occurs before age six, with best results yielding before age two. However, this does not mean that older patients will not have any success with strabismus therapy and treatment. There are numerous other studies that demonstrate that treatment after the age of 6 is very successful, and if not fully successful, at least partially improved.
- Orthoptics: Refers to the straightening of the eyes either via muscle strengthening or via the use of a prism in spectacles.
- Vision Therapy: Refers to the various procedures used to enhance visual-motor control. This may focus on training your brain to align the two eyes, break down suppression, process a single visual image, and fine-tune eye movements.
- Surgery: Surgery is usually used as a last resort to attempt to align the two eyes cosmetically, but can sometimes cause new symptoms if double vision, visual confusion, etc.