What is amblyopia?

Amblyopia, commonly called “lazy eye“, is a condition in which a person has reduced vision that is not correctable by glasses or contact lenses, and is not due to any eye disease. It results in seeing poorly out of one or both eyes. Not only is visual clarity reduced, but all visual skills are diminished, including depth perception and tracking ability. Amblyopia is the most common cause of visual impairment out of one eye in both children and young/middle-aged adults, affecting about 3% of the population. Not only is visual clarity reduced, but all visual skills are diminished, including depth perception and tracking ability.

Types of amblyopia

In general, amblyopia is caused by poor eyesight while the eyes are developing during infancy and early childhood. There are several types of amblyopia. Each of them is different in the way the vision is blurred, thus the brain does not learn to see correctly.

• Refractive Amblyopia is caused when a baby or young child has high or unequal amounts of far-sightedness, near-sightedness, or astigmatism and they do not get glasses or contact lenses to treat it when they are young. The extreme blur does not allow the connections between the eye and brain to properly develop.
• Strabismic Amblyopia is caused when a baby or young child has one eye that is constantly turned in, out, up or down. The turned eye is “shut off” or not used, and therefore does not develop vision properly.
• Deprivation Amblyopia is caused when a baby or young child has a condition that is blocking vision out of one or both eyes, such as a cataract or droopy eye lid, and the lack of visual stimulation stops the development of the visual centers in the brain.

How to treat amblyopia?

The best way to decrease amblyopia in the population is prevention. The American Optometric Association recommends comprehensive eye evaluations, in addition to pediatrician well-visits, at ages 6 months, 3 years, 5 years, and every year while the child is in school. Because of the importance of early detection for vision and ocular health conditions, many optometrists are providers for the InfantSEE™ (www.infantsee.org) program, which provides a complimentary comprehensive vision and ocular health evaluation for children under 12 months of age.

Many patients with amblyopia may not know that they have it until they have a comprehensive vision examination by an eye doctor. Amblyopia will not go away on its own. Although treating amblyopia during the “critical period” before seven years of age (varies among studies) gives the chances of the best possible vision, treatment of some types of amblyopia can take place at any age.

Management is dependent on the type of amblyopia that is present. If the child has refractive amblyopia, treatment starts with glasses or contact lenses in the correct prescription. Deprivation amblyopia is treated with surgery to correct the occlusion (such as taking out the cataract or surgically raising the lid). Treatment of all types often includes patching the eye with better vision or putting dilating drops in the better eye. This corrects amblyopia by training the brain to use visual signals from the eye with weaker vision, building a stronger connection between the brain and the weak eye, and allowing vision to develop in that eye. Patching is more effective in conjunction with an active vision therapy program, which also trains the eyes to work together, track efficiently, and to develop hand-eye coordination—all important skills for school success.