Amblyopia (Lazy Eye)

Amblyopia, commonly known as lazy eye, is a condition where vision does not develop properly during early childhood.

After the age of seven to eight years, the development of the child’s brain area that processes vision is almost complete. If the brain has not received clear images from the weak eye prior to that, it would be difficult to improve vision in that eye after the visual part of the brain development is complete. The eye is then said to be “amblyopic” or “lazy”. If left untreated, visual impairment can become permanent.

Children with amblyopia often do not complain of poor vision, and the problem may only be detected when vision testing is done. Occasionally, parents may notice a squint (where one eye appears to be misaligned), or a droopy upper eyelid in their children.

What causes amblyopia?

The main causes of amblyopia are uncorrected high refractive error (astigmatism, hyperopia, myopia), large differences in refractive power between the two eyes, and / or squint (strabismus). A minority are due to conditions that obstruct vision, such as droopy eyelids and childhood cataracts.

What puts my child at risk of lazy eye (amblyopia)?

Your child is at a higher risk if he or she has:

• High amounts of astigmatism, long-sightedness (hyperopia) or short-sightedness (myopia)
• Large differences in spectacle power between the two eyes
• Obstruction of vision by congenital defects such as droopy eyelid (ptosis), cataracts or other lesions in the eye
• Strabismus or squints where the eye that is misaligned is not used

Amblyopia is typically detected during an eye check-up since the child is usually too young to complain of poor vision. This should be carried out around the age of four by the family doctor, paediatrician or ophthalmologist.

To correct amblyopia, the child needs to be encouraged to use the lazy eye. This is usually done by patching the good eye, often for several hours a day.

Patching therapy may take months or even years, and is often more effective when it is started at a younger age. The basis of patching is to allow the lazy eye to be used more often that the other eye so that the lazy eye gets a chance to develop normal vision. If spectacles are required, the child must wear it at all times.

Illustration: Child patch

When amblyopia is detected too late (beyond 8 years old), it may not be possible to reverse the visual impairment. It is therefore important that you have your child’s eyes checked if you suspect a visual problem or are advised by the school health service to consult an ophthalmologist.