Amblyopia is reduced vision in an eye that has not received adequate use during early childhood. Amblyopia, or “lazy eye,” has many causes. Most often it results from either a misalignment of a child’s eyes, such as crossed eyes, or a difference in image quality between the two eyes (one eye focusing better than the other). Amblyopia is the most common cause of visual impairment in childhood. The condition affects approximately 2 to 3 out of every 100 children.
Amblyopia mainly occurs during childhood when the nerve pathway from one eye to the brain does not develop adequately. Generally, when the eyes are not working together and send a wrong or blurred image to the brain, the brain gets confused and may start to ignore the image from the weaker eye resulting in amblyopia. Strabismus is one of the most common causes of amblyopia. However, amblyopia can occur with or without strabismus and vice versa. Other causes include farsightedness, near-sightedness, and astigmatism or childhood cataracts.
Amblyopia mainly develops in the child of age group below 6. The signs mentioned below may not necessarily indicate that the child has amblyopia. In most of the cases, good eye and the brain make up for the problem so well that the child does not notice he/she has Amblyopia. Due to this reason, it is advised that children should get full eye check-up at 6 months, and again at 3 years.
The symptoms of Amblyopia include:
• Eyes do not appear to work together
• Dual vision
• Significant favoring of one eye
• Blurred vision
• Poor depth perception
• Poor vision in one eye
• A squint (either upwards, downwards, outwards, or inwards).
The goal of amblyopia treatment is to improve the visual acuity of the poorer eye, such that it’s acuity comes at par or within one or two lines of the good eye. With early diagnosis and treatment, the sight in the “lazy eye” can be restored. A recent NEI report suggests that older children can also benefit from amblyopia treatment.
Amblyopia is a condition of blindness when the brain stops using poor images sent by one or both eyes and is not able to fuse image from both eyes.
The brain simply pays very less attention to the images sent by the amblyopic eye. If one eye sees clearly and the other sees a blur, the good eye and brain will inhibit (block, suppress, ignore) the eye with the blur image. Eventually, the condition stabilizes, and can result in permanent decrease in Vision.
The eye produces poor images due to cataract (blurred image), ptosis (partial image due to lid drooping), crossed eyes, unfocussed/ distorted image (wrong power of lens/spectacles/retinal pathology).
The brain stops using image which is weaker or of no use. So despite the eye sending images to the brain, it refuses to use those images, hence making it ‘blind’. Slowly the brain forgets to use images from the eye.
The Brain ‘learns’ to ignore poor image or see bad image permanently after 8- 9 years of age when the development of brain and eye is complete. Hence it is reversible before 9 years of age and not later than that. So it is very important for parents to know about early eye examination which is crucial for all kids.
The poor image has to be corrected by treating the cause. Secondly till the cause is being treated the brain has to be stimulated with image from the eye that’s being ignored. This is done by patching. Preschool eye examination for all kids every year and thereafter is a must. As delay in diagnosis of lazy eye reduces the chance of improvement .This cannot be concluded without an eye examination.
Patching is a therapy to strengthen the weak or amblyopic eye. In patching the good eye is completely covered and the brain is forced to use the eye which is weak so that the brain does not forget to use the amblyopic eye . Occlusion is done for few hours depending upon the age of patient and the type and severity of amblyopia.
Patching should be guided by doctor. Set clear instructions and establish realistic forecast for wearing the patch. These will help your child to avoid struggle of wills over wearing the patch. Better the results if Children understand when and how long the patch has to be worn. In this period child has to engage to use the amblyoptic eye actively by reading, playing games, painting etc. To instruct them about the consequences if the patch is removed.
Treatments can be given by using spectacles with a proper patching depending on the cause.
It is the most commonly caused form of blindness in children in our country. Fortunately early eye examination and correct diagnosis with proper patching can reverse blindness caused by amblyopic eye. The earlier the treatment starts, the better is the response.
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