What is Lazy Eye
A condition formally known as amblyopia, a lazy eye is a visual condition that develops during childhood.
A lazy eye is essentially an eye that has not developed properly, and as such has impaired vision. Children with a lazy eye will tend to use the “good” or developed eye more frequently, which results in the muscles being strengthened and the disparity between the two eyes becoming larger. The more the lazy eye is underused, the worse it will become, and so children suffering with this condition may be asked to wear a patch or eye cover over the good eye to stimulate the muscles in the lazy eye.
It is estimated that 1 in 50 children will develop a lazy eye, and the condition will normally be apparent and therefore be diagnosed around the ages of four and five. Most cases will be detected during routine eye tests at school, while more serious cases will result in the affected eye being visibly different. If you suspect your child has a lazy eye, speak to your GP, as it may be that the need to attend further testing for diagnosis and treatment.
What are the Symptoms and Causes
This is because young children are more often than not unaware of problems with their vision, and so the condition is only detected when tested for. Older children of reading age are more likely to be aware of a lazy eye, and will likely report difficulties with activities like reading and writing as a result. If you do notice that your child appears to squint through one eye, or has difficulty looking in the same direction with both eyes at the same time, this can indicate weakness in the muscles and could be indicative of a lazy eye. Should your child suffer from cataracts or a condition called ptosis (when the upper eyelid droops down over the eye), this could also cause a lazy eye.
You can check your child’s eyesight yourself simply by covering an eye at a time, and asking them to carry out a task such as drawing, reading or writing. If they express a preference to one eye or another, or it becomes obvious that they enjoy stronger vision in one eye than the other, you may wish to make an appointment with your GP for further professional testing.
Lazy eyes are fairly common, with an estimated 1 to 5% of the population suffering from the condition. There are several known causes, such as refractive errors. These occur when the rays of light entering the eye are not focused properly due to structural problems within the eye, which can lead to conditions like farsightedness or astigmatism. When dealing with refractive errors, the brain starts to rely on signals from the eye with better vision, and starts to ignore the eye that has worse refractive errors. This means that the affected eye does not develop properly, and in effect becomes “lazy”.
Refractive errors can also lead to the development of a squint in older children, which is another cause of a lazy eye. An estimated 1 in 20 children will develop a squint, a condition during which the affected eye will look up, down, left or right while the other stronger eye looks straightforward. This discrepancy between the visions returned to the brain from each eye can cause things like double vision in some children, while in other cases, the brain will ignore the images returned by the squinting eye which results in it becoming lazy.
How to Diagnose and Treat Lazy Eye
When welcoming a new baby, parents will be provided a Personal Child Health Record (PCHR), in which they will find milestones for visual development. These include guidelines about when they should respond to colourful objects, recognise faces, and express interest in shapes for example. Should you notice any failure to meet these milestones, you should consult with your GP straight away to identify any issues with visual development.
It is recommended that children begin to undergo eye tests around the ages of four and five years of age, as it is best for the condition to be diagnosed and treated before a child turns six. These tests are important, as at this age, children often don’t realise that there is a problem with their vision. If you notice your child squinting or having obvious difficulty when using one eye compared with the other, you may wish to follow up with your GP as soon as possible for testing. If your ophthalmologist suspects a lazy eye, they will often test for other conditions as the same time, such as the development of a squint or farsightedness.
Treatment for a lazy eye is most effective when started at a young age, and your ophthalmologist will likely suggest one of two methods of treatment. One involves limited the use of the stronger, unaffected eye, therefore stimulating muscle development in the lazy eye. Your Ophthalmologist may provide your child with a patch to wear over the good eye, or in some cases prescribe eye drops that dilate the pupil in the good eye to blur the vision. It’s important to note that this method is best employed early on, and that treatment started after the age of eight is less likely to be as effective.
Alternatively, another form of treatment is to correct the root cause or underlying vision problem that is causing the lazy eye. One such treatment would be the prescription of eyeglasses, which can treat either farsightedness or nearsightedness. Glasses can also correct a squint, a common cause of a lazy eye. In teenagers and adults, contact lenses can of course take the place of glasses.
In a worst-case scenario, surgery may be required to remove cataracts that could be hindering the development of the eye muscles, or to strengthen the muscles directly and counteract a squint. Speak to your GP and Ophthalmologist about the best method of treatment for your child.