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    What is a lazy eye?

    By Dr Nirosha Paramanathan, FRANZCO

    The term ‘lazy eye’ is incorrect. The more accurate description would be ‘lazy brain’ as it is the brain that doesn’t learn to see and not the eye itself.

    Until around the age of 7, the seeing part of a child’s brain is still developing. During these critical years the brain is vulnerable. Anything that prevents each half {right and left} of the ‘seeing brain’ receiving a clear image, will block normal development of the seeing nerve pathways between the eye and brain. If one half of the brain and in worst case scenarios, both halves of the brain, do not receive clear images, the seeing parts of the brain switch off. The ‘seeing brain’ goes to sleep. If it is not awakened before the child reaches 7 years of age, it can never learn or re-learn to see, no matter what intervention.
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    There are a few things that we know for certain cause the brain to become lazy. The easiest one that you as a parent can identify is strabismus or squint. The common term squint again is not helpful as it is widely understood to mean squeezing shut the eyelids. When the term squint is used medically, it means that one or both eyes do not look straight ahead. The eye/eyes can turn: in towards the nose, out towards the ear, up, down or even a combination of these 4 positions. As long as the eye is not looking straight ahead the ‘seeing brain’ does not get a clear image and so switches off.

    Another cause, a little less easy for you to identify, is something that physically blocks the eye seeing a clear image. If the eye itself doesn’t see a clear image it is unable to relay a clear image to the brain and again the brain switches off. Things that can block the eye seeing include a drooping upper eyelid, a scar on the cornea {clear glass at the front of the eye}, a cataract {cloudiness} in the lens inside the eye or a tumour inside the eye.

    The final cause, is one that only an eye care specialist can pick up. It is also the cause that is most easily fixed if identified early. Some children’s eyes need glasses to help focus. Without glasses the focusing mechanism of their eyes can only manage to get a blurry image. This blurry image is relayed to the brain and because it is very blurry, the brain again switches off.

    The good news is that in this critical period until around the age of 7, as much as things can go wrong, if they are picked up early, they can also be fixed. The ‘seeing brain’ can be woken up and trained to see. The younger the child is when we pick up the abnormality the better our chance of fixing things to give that child perfect vision. The later in the critical period we try to fix things, the harder it is to give a child normal vision.

    We all aim to give our children the best start in life. This means having two eyes, each seeing perfectly, and both working together. If you have any questions, please don’t hesitate to call me.