What is anisometropia?
Our eyesight develops from birth and consolidates around the age of 7-8. During this stage, it is fundamental that the image reaching the brain is clean.
If this process does not work correctly and the visual capacity of one or both eyes decreases, it causes amblyopia, also known as “lazy eye”.
To treat amblyopia, we must first identify the cause, correct the refractive error with glasses or contact lenses, eliminate any visual hiderance (cataract surgery, corneal opacity) if necessary, and make the "lazy eye" work harder.
To do so, occlusion of the healthy eye with a patch is the most effective measure with the best results to date. The time and schedule for occlusion will depend on the degree and cause of the amblyopia and the child's age.
At the same time, there are other alternatives to occlusion, which are categorised under the term "penalisation". Their purpose is to make blurred the eyesight in the healthy eye.
This may be optical via glasses with an inexact prescription or filters in the healthy eye, or pharmacological through the application of eyedrops that dilate the pupil of the healthy eye impeding its focus.
These measures are a second therapeutic option for children who find occlusion difficult in cases of mild amblyopia or even by maintaing the vision reached after use of the patch.
The chance of lazy eye recovery is high if diagnosed and treated before the age of 4, the age at which it gradually decreases to become practically nil from the age of 9-10.
What we do not learn to see in our first years of life cannot be recovered later on in adult life. Not acting in time may condemn the child to having a lazy eye for life, which is why early diagnosis is vital.
This is why all children, even if they do not have any symptoms, should have a full eye examination by a specialist at the age of 2-3.
In general, children do not like having their good eye covered. It is fundamental that parents and teachers get involved so that the treatment works.
To improve compliance, we must try to keep the child occupied with any kind of activity they like while they are wearing the patch. Another option for smaller children is to put a patch on their favourite dolls or decorate their patch with drawings, although nowadays there are models with drawings and a range of colours that are more attractive for little ones.
On occasions, recurrence may happen upon suspending use of the patch. However, if the patient follows the instructions regarding the occlusion schedule and guidelines and visits the ophthalmologist regularly, then this complication is practically nil or non-existent.
Although the materials currently used are well tolerated even by children with atopic skin, sometimes periocular skin irritation may occur. To minimise and alleviate its appearance, a hydrating cream should be used and, in turn, you should apply the patch at a different angle or use different sized patched to give the skin time to recover.
Frequently asked questions
Ideally, the patch should be placed directly on the skin. If the patch if applied to the glasses lens, the child may look over the top or under it and even out the sides, making sensory rehabilitation ineffective. Patches are now manufactured using hypoallegenic materials which are well tolerated.
To guarantee the best response to treatment, in addition to putting the patch on the "good eye", we must be certain that while the child is using it that it is stimulating the affected eye. To do so, occlusion is recommended in the morning time slot, then let the child be more active preferibly during school time and reading time when they are using their electronic devices (tablet, videoconsoles, etc.). Making a routine of the patch and using it when the child is not tired, is in a good mood and doing some kind of activity they like, will guarantee better compliance. Children often "protest" and are reluctant to wear the patch. The family and school teachers need to get involved, so that the treatment is a success.
Until present, the most effective treatment for amblyopia, demonstrated by a multitude of scientific studies and backed by the experience of specialist ophthalmologists, is occlusion of the good eye using a patch. There is no scientific evidence to prove that visual therapy is useful to rehabilitate the lazy eye. Doing it may lead to delayed diagnosis and treatment of certain pathologies in which time is a fundamental factor in its resolution, as is the case with amblyopia.