Amblyopia is often called a “Lazy Eye” and implies reduced vision, in an eye which has not received decent visual stimulation during critical developmental stages during early childhood.
Our eyes focus and convert light into the nerve signals which are transmitted along our optic nerves to our brains, where they are processed and interpreted as vision. Amblyopia is sometimes called “a lazy eye” because we are not able to process the visual information from the affected eye. Even when it has been corrected with lenses.
Our ability to focus accurately develops in the first 4-6 months after birth. If the retinal images aren’t similar and the child favours vision from one eye. The visual pathways to the brain from the poorer eye are under stimulated and may not develop normally. This causes a developmental delay which may be permanent if it is not treated appropriately. Similarly this may happen when there is an eye-turn or overly droopy eyelid present.
Amblyopia is therefore caused by any condition that affects normal binocular visual development. Most commonly from either a misalignment of a child’s eyes (turned or crossed eyes) or a difference in vision quality between them (one eye focusing better than the other).
Other causes may include congenital cataracts, droopy eyelids and anything that results in the child not using both eyes. In all these situations detailed information from one eye is ignored by the brain. If this persists, the vision centres in the brain never develop and learn to use this visual information properly.
If not treated early the child may never develop normal vision and may even be functionally blind in the amblyopic eye. Even though this eye is generally anatomically normal and healthy.
Common! Amblyopia is the most common cause of visual impairment in childhood. It affects approximately 2 or 3 out of every 100 children. And unless it is successfully treated in early childhood it persists into adulthood and for the rest of the person’s life. Amblyopia is the single most common cause of unilateral blindness.
Yes! With early diagnosis and treatment, the sight in the blurred eye can be improved. The extent of this improvement depends upon the initial cause, the age of diagnosis and quality treatment. Treatment generally involves balancing the optical correction in the two eyes, and may include patching the better eye.
The earlier the treatment is started the better! Ideally treatment is commenced before the child begins school. The earlier the visual imbalance is corrected and the visual system is properly balanced the better the outcome is. Younger children are often also easier to manage and are more amenable to the required treatment.
It is essential to treat the underlying cause. This may involve one or more of the following:
- Glasses are commonly prescribed to improve focusing and ocular alignment.
- Contact Lenses are sometimes a better way of correcting the visual error.
- Eye Patching is often used to stimulate the neurological pathways of vision in the non dominant eye.
- Eye Drops are occasionally used to after patching, or when it is not appropriate
- Eye Exercises and visual therapy may be recommended to teach comfortable use of the eyes together.
- Surgery may be required on the eye muscles to straighten the eyes, if non-surgical means are not successful. Our eyes need to be aligned for them to work together.
Treating amblyopia involves facilitating normal binocular function. This is done by encouraging the child to use the eye with reduced vision after removing the obstacles that caused the imbalance initially. Stimulating visual discrimination in the amblyopic eye helps stimulate and activate the vision centres that interpret and process visual information and so develop more completely.
Don’t hesitate to contact us if you have any questions or you think your child may have amblyopia