As each new school year approaches, we see many 5 year olds getting their first eye exams for their kindergarten requirements. A problem that seems to sneak past parents is amblyopia (functional lazy eye). With amblyopia, one strong eye continues to visually develop and the other weaker eye is functionally ignored or suppressed by the brain. If the blurred weaker eye remains untreated early in life, then the visual potential may be reduced for life. Major causes of an amblyopic eye include; an eye turn (strabismus), opacities in the eye and unequal focusing between the eyes (refractive) causing blurred vision in one eye.
Parents will notice a large eye turn but not subtle misalignments. A small eye turn may cause just as much vision loss as a large eye turn. Treatment depends on the cause of the turn and it can then be corrected with glasses, prisms, or surgery. Congenital cataracts, inflammation within the eye, tumors and other eye problems all can cause amblyopia by blocking clear vision to the eye leading to the suppression and amblyopia. Infant wellness eye exams can pick up many of the issues and some cataracts can be detected by a pediatrician shortly after birth.
Refractive amblyopia occurs when there is a large difference in the prescription between each eye. The brain wants to do the least work possible and will pay attention to the eye that has a clearer image or that requires the least focusing power. We treat it aggressively with the constant use of eyeglasses allowing the poorer seeing eye to focus light properly onto the back of the eye. This allows the brain to get equal stimulation for vision from each eye. In many cases, the use of eyeglasses alone will not alter the connections that the brain formed. For those patients, a prescribed therapy regimen of patching the stronger eye forces the child to use the weaker eye. If problems arise in the compliance with patching, we can blur the vision in the stronger eye by altering the prescription or with special eye drops. Patching may take weeks to months to help balance out the visual clarity between the eyes and may continue on a part time basis for a few years.
The best time to treat amblyopia is early in life. If an amblyopic eye is left untreated a permanent loss in vision will likely occur and depth perception of 3D images may be lost. Also if untreated, should the stronger eye develop vision loss due to an accident, infection or inflammation, the poorer seeing amblyopic eye may be all that remains. This then leaves a patient with a permanent blurred view of the world. Treatment and diligence by parents is key for the success of clear vision in both eyes. If amblyopia isn’t detected until after early childhood, treatments may not be successful.