Vision relies on the eyes, the optic nerve and brain processing of visual information. Amblyopia, or "lazy eye," diminishes vision as the brain learns to ignore input from a weak eye; if left untreated, amblyopia can cause permanent visual impairment. Although there are different types of amblyopia, once any issues with the eye are resolved, the treatments to strengthen the eye-brain connection itself are the same. Amblyopia therapy works best in young children, whose eye-brain connections are still forming.
Patching
The simplest treatment for amblyopia is patching the stronger eye for several hours each day. Blocking the input from the stronger eye forces the brain to use and strengthen its connection with the weaker eye; over time, the connections approach normality and vision in the weaker eye improves. Although patching can be highly effective for young children, the major problem lies with getting them to wear the patch long enough for it to do its work.
Atropine
Atropine eye drops work along the same principle as the patch: the drops temporarily blur close-up vision in the stronger eye, forcing the brain to rely solely on the input from the weaker eye. Drops are administered daily or a few times per week. Atropine drops might offer a good alternative to the patch, but they do not work as well if the stronger eye is near-sighted.
Clinical Studies
A clinical study sponsored by the National Eye Institute found that atropine drops once per day were as effective as patching for improving vision in young children after six months of treatment. Although patching improved vision more quickly, it posed problems with compliance. Another study sponsored by the National Eye Institute found that two hours of patching per day worked just as well in young children as six years, a result that should encourage better compliance.
Prognosis-Children
When amblyopia is detected and treated early, most children show significant improvement in vision after a few weeks to months of treatment, according to the Mayo Clinic. Younger children have the best odds for improvement, because the connections between the eye and the brain fully form between six and nine years of age. Results from a clinical trial sponsored by the National Eye Institute show that even some children as old as 17 can gain significant improvement of vision in the affected eye after treatment.
Prognosis-Adults
The National Eye Institute states that while scientists are studying treatment of amblyopia in adults, the research is limited and effectiveness is unclear. In a study by Thompson publishedin the July 2008 issue of "Current Biology," vision improved in amblyopic adults stimulated with special magnetic fields, but the results lasted only 30 minutes. In the October 2009 issue of "Vision Research," Dr. Levi reviewed Perceptual Learning treatment for amblyopic patients. Intensive practice of a specific visual task--for example, identifying a letter in a jumbled background--can improve performance on that task and might improve overall vision in adults, but randomized clinical trials have not been done.
References
- Mayo Clinic.com: Amblyopia
- National Eye Institute: Amblyopia Facts
- National Eye Institute: Amblyopia Press Release
- "Vision Research"; "Perceptual Learning as a Potential Treatment for Amblyopia: a Mini-review"; D.M. Levi and R.W. Li; October 2009.
