Amblyopia (lazy eye)

What is Amblyopia?

Amblyopia is commonly known as lazy eye and is where the vision is reduced in one of the eyes because the amblyopic eye and the brain are not working together properly. The eye itself looks normal, but it is not being used properly as the brain is favoring the other eye. In both cases, one eye becomes stronger, suppressing the image of the other eye. In a minority of cases this may result in a reduction of vision in both eyes. It is estimated that three percent of children under six have some form of amblyopia.

With early diagnosis and treatment, the sight in the amblyopic eye can be restored, however if this condition persists, the weaker eye may becomes useless.

Causes of Amblyopia

Both eyes must receive clear images during the critical period. Anything that interferes with clear vision in either eye during the critical period (birth to 6 years of age) will result in amblyopia (a reduction in vision not corrected by glasses or elimination of an eye turn). The most common causes of amblyopia are constant strabismus (constant turn of one eye), anisometropia (different prescriptions in each eye), and/or blockage of an eye due to trauma, lid droop, etc. If one eye sees clearly and the other sees a blur, the good eye will inhibit (block, suppress, ignore) the eye with a blur. Thus, amblyopia is a neurologically active process. This inhibition results in a permanent decrease in the vision in that eye that is not corrected just with glasses.

Diagnosis of Amblyopia

Since amblyopia usually occurs in one eye only, many children may be unaware of the condition. As far too many parents fail to take their infants and toddlers in for an early comprehensive vision examination, many children go undiagnosed until they have their eyes examined at the eye doctor's office at a later age.

The most important diagnostic tools are the special visual acuity tests other than the standard letter charts used by the eye doctor. Examination with cycloplegic drops can be necessary to detect this condition in the young.

Treatments for Amblyopia

Amblyopia cannot be correced by glasses or contact lenses and is not due to any eye disease.

If not detected and treated early in life, amblyopia can cause a permanent loss of vision with associated loss of stereopsis (two eyed depth perception). Detection and correction before the age of two offers the best chance for restoration of normal vision. However, treatment can improve this condition even in adulthood

Amblyopia can be treated fairly successfully between the ages of 2 and 6, but the success decreases with age. The best results from treatment occurs between ages 6 mos. to 2 years.

Treatment is usually simple, employing glasses, drops, exercises and/or patching. Though true amblyopia can not be cured (after the age of 6) treatment for the older child is usually successful in improving vision and should be attempted. Treatment of amblyopia after the age of 6 is not dependent upon age but requires more effort including vision therapy. Every amblyopic patient deserves an attempt at treatment.

It should be remembered, that amblyopia causes more visual loss in the under 40 group than all the injuries, and diseases combined in this age group.

 

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