A lazy eye can develop in babies, toddlers and children, but not after primary school age. With a lazy eye, the vision of one of the two eyes is significantly reduced because its development has lagged behind in early childhood. With a lazy eye, the connection with the brain has never been able to develop properly. This is because at a young age the lazy eye systematically sends less good signals. Lazy eye is a common condition that can largely be prevented through early detection. Adults can also have lazy eye, because it was not diagnosed and/or remedied in childhood. Until recently, there was no effective treatment for adults with lazy eye.
- What is amblyopia (lazy eye)?
- Symptoms of a lazy eye
- Causes of a lazy eye
- Visual aberration of the eye
- Genetic predisposition
- Examination and diagnosis
- Routine examination
- Eye doctor
- Treatment of a lazy eye
- Start as early as possible
- Multiple possible treatments
- Adults with a lazy eye
- Eye surgery
- Video glasses
What is amblyopia (lazy eye)?
Amblyopia, better known as lazy eye, is poor vision in one of the two eyes because its development is suppressed in early childhood. With a lazy eye, the connection with the brain has never been able to develop properly. This is because at a young age the lazy eye systematically sends less good signals. If this situation continues until the fourth or fifth year of life, the vision in the affected eye remains permanently impaired and it is referred to as a lazy eye. It is estimated that three percent of children under the age of six have some form of amblyopia. Usually only one of the two eyes is lazy, but a ‘lazy eye’ can rarely occur on both sides.
Symptoms of a lazy eye
A lazy eye has the following symptoms:
- Poor vision with the so-called ‘lazy eye’ and even with glasses, vision is not improved.
- Seeing less depth, which makes it easier for the child to stumble or fall and more difficult to grasp something because the child grabs next to it.
- Squinting or cross-eyed is also possible, where both eyes are not looking in exactly the same direction.
There are not always noticeable symptoms of a lazy eye, especially in a young child. A lazy eye is then easily overlooked.
Causes of a lazy eye
The most common cause of amblyopia is strabismus, where there is an inability to focus both eyes on one fixation point. Both eyes look in different directions. They capture two different images that cannot be merged. In that case, the image of the eye looking to the side is suppressed. Without treatment it becomes a lazy eye.
Visual aberration of the eye
Another cause of a lazy eye is when the image of one eye is significantly less sharp than the other, due to a deviation in the eye’s strength. This blurred image cannot be merged with the sharp image in the brain, causing the less seeing eye to be suppressed. Over time, this can also cause a lazy eye.
Finally, clouding of the normally clear parts of the eye, for example due to an eye disease such as cataract, can also lead to a lazy eye. Due to the cloudiness, a sharp image is not formed, which can cause a lazy eye.
A certain hereditary predisposition may play a role in the development of a lazy eye.
Examination and diagnosis
Since amblyopia usually occurs on one side, many parents and children are not aware that one eye sees less well. The overall visual acuity with the two eyes together is more than sufficient. The reduced vision is usually noticed during a routine examination or the parents notice strabismus, for which they consult the ophthalmologist or orthoptist.
A baby who is clearly cross-eyed is referred to the ophthalmologist at an early stage. At the clinic, a test is administered to all children before the second year of life to determine whether there is (a tendency to) strabismus. At the same time, it is checked whether the vision in one or both eyes is impaired. And at the age of four, the child’s visual acuity is measured with a picture test. It is then checked whether the child recognizes pictures from a certain distance. If abnormalities are found, a referral is made to an ophthalmologist, who will determine the cause. Various studies are being done to determine the exact cause of amblyopia.
Treatment of a lazy eye
Start as early as possible
It is important to start treatment as early as possible, because after a certain age visual acuity can no longer be improved. The younger the age of the child when treatment is started, the better the prognosis.
Multiple possible treatments
The treatment of a lazy eye can include:
- Correction of the spectacle prescription deviation. Children with a glasses prescription deviation are prescribed glasses or contact lenses.
- Occlusion (taping). The lazy eye is stimulated by covering the good eye for some time every day. In addition to wearing glasses, the lazy eye sometimes also needs to be taped (see below).
- Pharmacological penalization (drops). By instilling certain eye drops in the good eye, the good eye will see less well than the lazy eye. This stimulates the lazy eye to look. This treatment is only possible if the difference between the two eyes does not exceed 20% and the bad eye must see at least 50%.
- Other treatments. If there is an eye disease, it will need to be treated.
Adults with a lazy eye
Adults can also have a lazy eye. But until recently there was no effective treatment for adults with lazy eye. On ophthalmological examination they often have a normal-looking eye, but the eye has not developed before the age of 8. Eye surgery no longer has any effect on adults. Surgery may only be useful for cosmetic reasons. Thanks to video glasses and the well-known game Tetris, lazy eye can now also be remedied in adults.
A group of Canadian scientists from McGill University have discovered that with video glasses it is possible to show each eye a different part of the game Tetris.¹ The blocks are visible in one eye, and the ‘floor’ on which the blocks are visible in the other. should end up and where lines should be formed to gain points and progress in the game. If the wearer of the glasses wants to play the game well, both images must be combined and that takes effort from the brain. The brain is, as it were, forced to make both eyes work properly (together), with the result that the blurred vision gradually disappears. The researchers hypothesize that lazy eye can also be remedied in this way in older people.
- McGill University Health Centre. ‘Lazy eye disorder – A promising new therapeutic approach. www.eurekalert.org/pub_releases/2013-04/muhc-ed041913.php
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