Doctor, is my baby cross-eyed?

This is one of the most common questions that Dr Quah Boon Long, head and senior consultant of Paediatric Ophthalmology and Strabismus Service at the Singapore National Eye Centre, hears from the parents of his baby patients.

'Most of the time, it's just a pseudo squint and nothing to worry about,' said Dr Quah.

A pseudo squint is common in Asian children. Due to folds of skin covering the inner part of the eye or a flat nose bridge, a baby might appear to squint. A medical examination will determine if it is a true squint or a pseudo squint, for which no treatment is needed.

A true squint, or strabismus, is a real vision problem which can cause amblyopia, commonly known as 'lazy eye'.

Dr Quah said that although a squint can cause amblyopia, the latter is a different condition.

Amblyopia is poor vision in an eye that did not develop normally during early childhood. After the age of about five years, the development of the part of the brain that processes vision is almost complete.

The decrease in vision results when one or both eyes send a blurry image to the brain. If the brain has not received clear images from the weak eye, it becomes difficult to improve the vision in this eye after the brain is completely developed.

The eye that sends the blurry vision is then said to be amblyopic or lazy. Amblyopia can develop in both eyes.

When a lazy eye is not diagnosed and treated before the age of five, a child's binocular vision could be affected permanently, said Dr Low Cze Hong, an ophthalmologist at Mount Elizabeth Medical Centre.

The child may grow to have problems with depth perception, he added.

A depth perception problem can lead to difficulty in carrying out tasks like throwing, hitting or catching a ball, threading a needle and even shaking someone's hand.

Dr Low said it is important for parents to send their child for professional eye checks from a young age so that any vision problem can be detected early.

A lazy eye that is caused by long- or short-sightedness can be corrected by prescription glasses which will re-balance the focus of the eye.

Wearing an eye patch is also a common treatment. It is the good eye that is patched so that the brain has to use the lazy eye exclusively.

'It is important to start the patching treatment early as it is far less effective for children above six years old,' said Dr Quah.

A child with a lazy eye does not need to wear a patch all the time. Depending on the severity of the condition, it may be worn for three to six hours a day.

The treatment usually lasts several months and, in many cases, the lazy eye will usually improve in about three months.

In the case of 15-year-old Benjamin Lim, who developed amblyopia when he was four years old, he sought treatment a little too late.

'We didn't think it was very serious and thought it would go away when he grew older,' said his father Raymond Lim, 47, a senior manager at an IT firm. He discovered his son's condition as the boy was squinting.

Benjamin's condition did not improve. When his parents took him to an ophthalmologist about four years later, a patch was recommended.

As the condition affected both his eyes, the patch had to be switched between them every day.

He put up with the patch for less than a year. As the patching did not produce much improvement in his condition, Benjamin eventually had to undergo surgery on both eyes when he was 10 years old.

Dr Quah performed the two-hour surgery at the Singapore National Eye Centre, with Benjamin under general anaesthesia. The boy took less than a week to recover.

The Secondary 3 student now wears spectacles for his short-sightedness but there is no hint of lazy eyes.

'You can't tell that I used to have them at all,' he said.

This article was first published in Mind Your Body, The Straits Times on Oct 9, 2008.