Strabismus, the technical term for eye turn, occurs when one of the two eyes does not aim at the spot one is looking at. An eye may turn inwards (esotropia), outwards (exotropia), or upwards hypertropia. The eye turn may occur some of the time (intermittent) or all the time (constant). When the eyes are not aligned the following may happen: the patient sees double (usually occurring when the eye turn develops after 6 years of age); one eye is suppressed or turned off to avoid double vision; there is a loss of two-eyed depth perception (stereopsis or 3D); and/or the eyes develop abnormal binocular coordination. If one eye turns all the time or if the eyes have different eye glass prescriptions, e.g. one is mildly farsighted while the other is markly farsighted, then one eye sees clearly while the other sees blurred. The lack of clear vision in one eye will cause it to develop Amblyopia (commonly called lazy eye).
To develop normal vision babies require clear images in each eye which are perfectly aligned. If one of the images is blurred (due to astigmatism and/or significant optical difference between the two eyes) or misaligned (strabismus), during the early development years, then the brain interferes with the development of normal vision. The brain can not deal with the inequality of image. The "good" eye will inhibit the other eye causing the visual pathways not to develop normally. This semi-permanent decrease in vision is called Amblyopia. Even with glasses the amblyopic eye will not see 20/20 or normally. It is important to understand that the reduction in vision can not be corrected only by the prescription of glasses. However, equalization of the images is the first step in treatment, i.e. glasses. After getting new glasses for your child we should measure the visual acuity of each eye. This may be performed at our office or at your home.
To test the vision in the right eye at home cover the left eye and then click here to view the interactive acuity tester. Then cover the right eye and test the vision in the left eye. For young children use the picture chart.
The eye must be treated with glasses, patching, drops and exercises. (For more information about patching and obtaining
patches click here) The "lazy" eye needs to be made to work. Amblyopia develops relatively early in life (usually before the age of 2, but up to 6 or 7). Both amblyopia and strabismus must be attended to during the early years of life. Children rarely grow out of strabismus. Amblyopia causes more permanent loss of vision in the under 40 years of age than all the combined diseases and trauma. These common conditions which affect approximately five percent of children must be detected and treated early. The earlier the diagnosis and treatment the better the results.
We recommend that the first examination for your child be at 9 mos. of age.
Treatment of amblyopia and strabismus may include glasses, patches, exercises and possibly even surgery. (see Testimonials). Early treatment is clearly more effective, however, we have often been successful in treatment of both amblyopia and strabismus in later years. While surgery does have a place in treatment -- it eliminates the mechanical demand to align the eyes and makes them appear straighter -- surgery rarely makes the eyes work together normally. The best chance of developing normal or near-normal binocular vision requires vision therapy to re-educate the eyes. Both visual acuity and eye coordination can be dramatically improved with vision therapy. Our office specializes in strabismus and amblyopia. Dr. Cooper has trained over 500 doctors in the area of strabismus. He is also on the editorial board of Binocular Vision and Eye Muscle Surgery, and has authored over 60 research articles in the area.
For more information on lazy eye and strabismus, visit strabismus.org, (a detailed comprehensive WEB site written by Dr. Cooper devoted to amblyopia and strabismus), children-special-needs.org or visiontherapy.org.