Amblyopia, aka “Lazy Eye”
Amblyopia, also known as "lazy eye" is poor vision due to lack of normal development of sight. It is a very common condition, affecting 2-3 of every 100 people. Normally, children’s eyes continue to develop from birth until age 9 or 10. Amblyopia is caused by conditions that interfere with that normal development. There are three major causes of amblyopia:
- Unequal focus. In the healthy eye, equal focusing problems can be corrected with glasses. If there is unequal focus because one eye is more nearsighted, farsighted, or has astigmatism, amblyopia may occur. In these cases, the out of focus or blurry eye "turns off" and becomes amblyopic. The brain ignores that blurry eye, and it develops poor vision. This type of amblyopia is very difficult to detect, because the eyes look normal.
- Strabismus or misaligned eyes can cause amblyopia when the brain ignores the crossed eye to avoid seeing double. The straight eye usually retains normal vision. Some children may have a large amount of crossing, which is easy to detect. Others have a very tiny amount, which can be difficult to see at home, but can still cause amblyopia.
- Cloudiness of the normally clear parts of the eye can prevent a sharp image from reaching the inside of the eye. One example of this is a cataract, or cloudiness of the lens of the eye. Although far less common in children than in the elderly, cataracts can occur in young children.
Amblyopia is diagnosed by finding a difference in the vision of the two eyes. A vision screening exam will help detect this, though further diagnosis and treatment will need to take place with a pediatric ophthalmologist. A pediatric ophthalmologist will help determine which of the three causes of amblyopia are occurring in your child. Sometimes, more than one can exist at the same time. During that visit, the entire eye will be carefully examined to check for other causes of poor vision.
Treatment of amblyopia involves using the weak eye. Covering or patching the stronger eye accomplishes this by making the weaker eye work alone. Glasses may also be prescribed to correct the unequal focus. Patching often needs to be done while wearing glasses full time in order to completely treat amblyopia. If surgery is required for straightening the misaligned eyes, patching or glasses may continue afterward. All forms of treatment need to be started as soon as possible. Amblyopia can become permanent if not treated at an early age.