Strabismus - Children's Ophthalmology
Strabismus is a condition in which the eyes are not properly aligned with each other. It typically involves a lack of coordination between the extraocular muscles that prevents bringing the gaze of each eye to the same point in space and preventing proper binocular vision, which may adversely affect depth perception.
Strabismus can be either a disorder of the brain in coordinating the eyes, or of one or more of the relevant muscles' power or direction of motion. It may be convergent or divergent, dependent on whether the squinting eye is directed inwards or out respectively. Strabismus is called tropia if it is permanent and phoria if it is latent and occurs only after fatigue or focus on close objects.
Normally our brain receives two similar images from each eye that are identical and thus binocular stereoscopic vision is achieved. In case of strabismus it is possible that the brain rejects the image received from the swuinting eye to anoid confusion and diplopia with a process called repression. This leads to the development of amblyopia - a situation known as the "lazy eye" - ie a large decrease of the visual aquity of the squinting eye.
As with other binocular vision disorders, the primary therapeutic goal for those with strabismus is comfortable, single, clear, normal binocular vision at all distances and directions of gaze.
Whereas amblyopia, if minor and detected early, can often be corrected with use of an eyepatch on the dominant eye and/or vision therapy, the use of eyepatches is unlikely to change the angle of strabismus. Advanced strabismus is usually treated with a combination of eyeglasses or prisms, vision therapy, and surgery, depending on the underlying reason for the misalignment. Surgery does not change the vision; it attempts to align the eyes by shortening, lengthening, or changing the position of one or more of the extraocular eye muscles and is frequently the only way to achieve cosmetic improvement. Glasses affect the position by changing the person's reaction to focusing. Prisms change the way light, and therefore images, strike the eye, simulating a change in the eye position.
Early treatment of strabismus and/or amblyopia in infancy can reduce the chance of developing amblyopia and depth perception problems. Most children eventually recover from amblyopia by around age 10, if they have had the benefit of patches and corrective glasses.