Amblyopia or "lazy eye", refers to reduced vision in an eye and that the vision cannot be corrected with glasses. Amblyopia is sometimes confused with the medical term strabismus, which describes an eye that wanders or crosses.

Amblyopia usually occurs in children when the visual system is still developing, before 7 or 8 years of age. If it is not corrected in childhood, these children may be left with permanent vision loss.

There are many causes of amblyopia, the most common being strabismus (drifting inward or outward of one eye). It also occurs when the vision in one eye is significantly different from the other, for instance, when one eye is very nearsighted and the other is normal or farsighted. Anything that prevents light from getting into the eye, such as scars on the corneal surface or cataracts, will cause amblyopia.

Treatment usually requires covering the preferred (stronger) eye with a patch, forcing the child to use the amblyopic or "lazy" eye. Drops rarely can be used to blur vision in the stronger eye to force the use of the "lazy" eye.

The number of hours per day and number of weeks or months that a child must wear the patch depends upon the severity and cause of his or her amblyopia. In children with very severe amblyopia and very poor vision in one eye, patching may last for months or years. In children with mild amblyopia, patching may be required for a short period of time.

The more severe the visual loss the greater number of hours per day will be required to restore the vision to normal. Amblyopia can not be corrected in all cases. If it is not picked up early, the vision may not respond fully to patching. Normally children will not respond to patching after they are 7 or 8 years old except in unusual circumstances. However, younger children will respond to patching therapy much more readily.

Glasses or eye muscle surgery or other intervention may also be required to correct the cause of amblyopia. Frequent follow-up exams are required to assess the visual improvement and response to patching.

Tips on patching

It is very common for children to resist wearing their patch, especially if the amblyopia is severe and their vision is poor in the "lazy" eye. In these cases the child will not see well while wearing the patch over the good eye and will frequently attempt to take the patch off.

Some children can be convinced to wear the patch with positive reinforcement and a simple reward system. Other children may require more stringent measures such as elbow restraints that physically prevent the child from pulling off the patch. Normally, patching becomes easier once the child has become accustomed to it. As the patching therapy proceeds the vision should improve, which in turn leads to better compliance wearing the patch. Remember, only you can force patching, and although children rarely like it, they will thank you when they are older.

Occasionally the skin around the eye become red and irritated from repeated patching. If this happens to your child, discontinue patching for two to three days until the redness has improved. Then, apply Maalox liquid antacid around the eye and allow it to dry before placing the patch on. In this way when the patch is removed it will peel off the dried film of liquid and be less likely to irritate the skin.

If your child wears glasses, patches may be adhered to the lens of the glasses although you should be certain that the child does not peek around the lens and patch. Another option if standard patches cause irritation, is to buy or make a pirate-style patch. Again, you should make sure that the child does not peek around the patch.

by David R. Weakley, Jr., M.D.

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