Lazy eye is also known as Amblyopia. Lazy eye is an early childhood condition where a child's eyesight in one eye does not develop as it should. The problem is usually in just one eye, but can sometimes affect both of them.
When a patient has amblyopia the brain focuses on one eye more than the other, virtually ignoring the weak eye. If that eye is not stimulated properly the visual brain cells do not mature normally.
The term lazy eye is inaccurate, because the eye is not lazy. In fact, it would probably be more accurate to say lazy brain, because it is a developmental problem in the brain, not an organic problem in the eye.
What are symptoms of Lazy Eye Syndrome ?
A child with a lazy eye wont be able to focus properly with one eye and as a result the brain starts ignoring weaker images.
The signs and symptoms are as follows:
- Blurred Vision
- Double Vision
- A squint
- Eyes do not appear to work together
- Poor depth perception (of vision)
It is important for a child to have a vision check. In most countries the first eye examination occurs at the age of 3 to 5 years. It is especially important to have an early eye check if there is a family history of crossed eyes, childhood cataracts or other eye conditions
How is it caused ?
An imbalance in the muscles that position the eye: The muscle imbalance undermines the two eyes' ability to track objects together (move in harmony with each other, in a synchronized way, to be aligned onto an object that may be stationery or in motion.)
Strabismus or squint may be inherited; it could be the result of long- or short-sightedness, a viral illness, or an injury.
Anisometropic amblyopia – unequal eye powers or unequal refractive errors between the two eyes result in the brain acknowledging images from the eye with lesser power this makes it overlook the impulses being sent to it from the weaker eye .Thereby causing blunting or lazy vision developing in the eye with higher powers.The more the difference between the powers of the two eyes the deeper or worse is the amblyopia.
Stimulus deprivation amblyopia – This happens when light from an object to be viewed is obstructed from reaching the retina of One eye or both eyes. Thus the eye that is not perceiving images gets blunted vision.
Conditions within the eye that can obstruct the light rays from reaching the retina are corneal scars,cataracts, droopy or floppy eyelids,childhood glaucomas and eye injuries.
Very often we find children with locks of their hair falling and covering one eye thereby obstructing light rays from entering the eye and causing ambylopia.
This is a very avoidable circumstance.
How is Lazy eye diagnosed ?
Routine examinations play a very important role in the diagnosis of lazy eye syndrome.Each eye is tested separately to determine whether there is any short- or long-sightedness(refractive errors) and how serious it is. The child will also be carefully tested to determine whether there is a squint.
Comprehensive vision evaluations are highly recommended for infants and pre-school children. Otherwise, many children go undiagnosed until they have their eyes examined at the eye doctor's office at a much later age.
What are treatment options for Lazy Eye Syndrome?
In practice a combination of both these methods give the best desired results.
1.Treating an underlying eye problem.
2.Getting the affected eye to work so that vision can develop.
- Treatment for underlying eye problems
Many children who have unequal vision - anisometropia - do not know they have an eye problem because the good eye and the brain compensate for the shortfall. Sadly, the bad eye progressively suffers and amblyopia (blindness) develops.
Glasses - a child with myopia (short-sightedness) or hypermetropia (long-sightedness) will be prescribed glasses. The child will have to wear them all the time so that the specialist can monitor how effective they are on improving amblyopia (vision problems on the lazy eye). Glasses may also get rid of a squint. Sometimes, glasses can solve the amblyopia and no more treatment is required. It is not uncommon for children to complain that their vision is better when they don't wear the glasses. They need to be encouraged to wear them for the treatment to be effective.
Cataracts - cataracts can be surgically removed with either local or general anaesthesia.
Ptosis (droopy eye lid) - the usual treatment for this is surgery.
- Getting the lazy eye to work
Occlusion (using a patch) - A patch is placed over the good eye so that the lazy eye has to work. As the brain is only getting data from that eye it won't ignore it. A patch won't get rid of a squint, but it will improve vision in the lazy eye.
The length of treatment depends on many factors, including the child's age, the severity of their problem, and how much they adhere to the specialist's instructions. The patch is usually worn for a few hours each day. A child should be encouraged to do close-up activities while wearing the patch, such as reading, coloring or schoolwork. A child with amblyopia does not have to wear a patch all day; three to four hours daily for a total of twelve weeks is all that is usually needed to improve vision.
Encouraging the child to wear the patch when they are told to is important. If the child is old enough, explaining why the patch is so important helps. For some children, having to wear a patch is unpleasant, irritating and embarrassing.
Atropine eye drops - These may be used to blur vision on the better or good eye.Atropine dilates the pupil, relaxing the eye muscles and resulting in blurring when looking at things close up - this makes the brain appreciate images from the lazy eye ,making it work more. Atropinised eye is usually less conspicuous and awkward for the child, compared to the patch, and can be just as effective. Children who cannot tolerate wearing a patch may be prescribed eye drops instead.
It needs to be used strictly under prescription as it can have harmful side effects.
Surgery: Realigns muscles in the eyes, a more expensive and risky option than other forms of treatment
1) VISION THERAPY
- Vision Therapy
These are computer based sets of exercises that give a multiprong therapy to counter ambylopia.
a)Antisuppression therapy: First vision therapy removes the suppression from the brain of the lazy eye enabling the brain to acknowledge the visual imputs from the lazy eye
b)Stimulation: Once the brain starts recognising the lazy eye ,sets of computerised therapies are given to stimulate the brain cells to learn to understand the visual impulses from the lazy eye thus bringing the brain to comprehend and analyze the impulses from both the eyes at power with each other.
c)Binocularity: Vision therapy further helps the neural adaptation of the brain to the concept of binocularity.
This allows binocular interaction between the two eye allowing them to align, move, track on stationery and moving objects and develop a 3 dimensional vision with depth perception.
To quote Dr. Leonard J. Press, FAAO, FCOVD :
"Treatment of amblyopia after the age of 17 is not dependent upon age, but requires more effort including vision therapy.
It's been proven that a motivated adult with strabismus and/or amblyopia who works diligently at vision therapy can obtain meaningful improvement in visual function. As my adult patients are fond of saying: "I'm not looking for perfection; I'm looking for you to help me make it better". It's important that eye doctors don't make sweeping value judgments for patients. Rather than saying "nothing can be done", the proper advice would be: "You won't have as much improvement as you would have had at a younger age; but I'll refer you to a vision specialist who can help you if you're motivated."
Some children require the stimulation of the visual cells in the brain by special medications that have been found safe for children.
The successful management of AMBYOPIA requires a synergistic approach with the use of several modalities available to the eye specialist.
It is a neural learning of the brain that is required. The therapy is time consuming and tedious for the parent and the individual but well worth and satisfying.