Laser eye surgery for Lazy eye

The medical name for a Lazy eye is amblyopia and it affects approximately 2-3% of children under 7 years old. Unless it is treated early, amblyopia will persist into adulthood and there is currently no treatment. The earlier the lazy eye is detected and treated the greater the chance it can be put right. Once you are beyond the age of about 7 years old, your eye is said to be fully developed and will not respond to any amblyopia treatment. The primary treatment of amblyopia is patching, where the good eye is covered for a few hours each day (this can vary) in attempt to make the lazy eye work harder and hence improve the vision. The earlier the patching is started the better the chances of the eye improving. The reason for this is that during your early childhood your eye is still developing meaning improvements to the vision can be made easier.

There are many causes of a lazy eye but the 2 most common reasons are as follows:

• Squint: A squint (strabismus):  This refers to a turn in your eye and in no way refers to people screwing their eyes up when they are trying see better. A squint can make your eye turn in or out and it is this turning eye that develops the amblyopia.
• Anisometropia: This is the medical term for when you have a difference in the prescription in your 2 eyes. An example of this would be if your good eye has no prescription and your bad eye has a prescription of +3.00.

Both a squint and a difference in your prescription (anisometropia) have the same effect on your eyes when they are developing as a child.  Put simply, the bad eye (squint or highest prescription) is not receiving all the same information as your good eye whilst it is developing. As a result of this, the seeing part of your brain (visual cortex) does not develop properly meaning you cannot see the same detail as you can with your good eye. Most people assume that a lazy eye refers to your eye being lazy, but it is actually the visual part of your brain that is ‘lazy’. The actual lazy eye itself is the same as the good eye.  It collects all the information via your retina (the same as your good eye does) and sends it to your brain (via the optic nerve), it is when it gets here that the problems occur. This is why there is currently no treatment for a lazy eye once you get beyond the age of 7. This is the reason most children are discharged from the care of the hospital at this age.

Lazy eye and Laser eye surgery

One of the most commonly asked questions from amblyopic patients and parents of amblyopic children is will laser eye surgery be able to correct the lazy eye? Most people (and parents) assume that a lazy eye can be corrected by laser eye surgery and this is mainly down to the misunderstanding of the condition. If you realised that it was the seeing part of your brain that was the ‘lazy’ part then it would make more sense that a lazy eye could not be corrected by laser eye surgery.
The easiest way to understand what laser eye surgery can do for a lazy eye is as follows:
Laser eye surgery can give you the same vision that your lazy eye currently has with glasses or contact lenses but without having to wear glasses or contact lenses. So if you can see half way down the chart at the opticians with your glasses or contact lenses, then following laser eye surgery you will still only be able to see half way down the chart but only you won’t have your glasses or contact lenses in! Your good eye however will probably still be able to see to the bottom of the chart and so you will continue to use that eye anyway.

Laser eye surgery on the good eye

Imagine the following scenario:

You are moderately long sighted. Your right eye is +3.00 Dioptres (this is what prescriptions are measured in) and your lazy eye is +6.00 Dioptres. With your glasses or contact lenses in, your good eye can see the bottom line of the eye test chart but your bad eye (with glasses/contact lenses) can only say the top letter. So you may say I just want to get my good eye lasered so I don’t have to wear contact lenses/ glasses any more. The problem lies in the fact that your surgeon will be reluctant to perform the procedure on your good eye in the small chance that something may go wrong. Although the chances of this are very slim as laser eye surgery risks are very small, there is still however small a risk. So if the surgery went ahead and something went wrong which left your good eye’s vision impaired, then you would be left to rely on your bad eye. Depending on how lazy the bad eye is, this may mean that you could no longer drive, carry on working etc

What most laser eye surgeons insist on is that they will only treat your good eye if your bad eye is not profoundly weaker. So if you imagine with glasses on your good eye can see the bottom line of the chart but you bad eye can see the second or third from bottom (i.e. not that lazy) then you may be suitable for laser eye surgery. All surgeons have slightly different criteria for this and so you will only ever know for certain if you have a laser eye consultation. But the most important thing to remember is that laser eye surgery can only give you the same vision as you can currently see with your glasses or contact lenses.