What is Amblyopia?
Amblyopia is the medical term for an eye disorder more commonly known as “lazy eye.” Amblyopia is caused by reduced vision in an eye. Frequently that eye has not been adequately used during childhood. Amblyopia most often result from refractive error. In other cases, it is caused by two eyes producing a difference in image quality (i.e. one eye focuses better than the other).
If amblyopia is not treated, the weaker eye may eventually become useless. However, early diagnosis and treatment can help restore vision in the weaker eye. Although amblyopia usually only affects one eye, both eyes can be affected if they are both deprived of receiving clear visual images. Amblyopia treatment can be successful at any age.
Lazy eye may cause strabismus (i.e. crossed eyes), which involves a misalignment of the eyes. It is better to treat refractive error prior to treating strabismus or immediately after squint surgery. Otherwise the condition can recur.
Amblyopia or Lazy can cause…
Some of the most common symptoms of amblyopia are:
- Poor depth perception
- Eyes that turn in or out
- Eye strain
- Squinting or closing one eye while watching TV or reading
- Tilting the head while looking at an object
Amblyopia and Treatment Options
Correction of refractory error is the utmost importance. Glasses and contact lenses have been traditionally used. If the child cannot wear either than laser vision correction may be option. Removing cataracts which obstruct vision may be required.
The lazy eye may be stimulated by exercise. At the same time the other eye can be surprised by fogged glasses, dilating it with atropine or patching it.
Dr. Khanna has treated a 26-year-old patient with lazy eye. He performed lasik eye surgery to correct the high anisometropia. The young man was able to change his driver’s license from a one eyed to a two eyed driver. He also cured the boys mother with Pi in Eye procedure. She was in her fifties. There is no upper age limit for treatment. Even though books and some doctors preach an upper limit of 11 years of age. It is true the sooner intervention is done the better the results.
It is important to know the not all lazy eyes are treatable. If there is optic nerve damage than outcome may not be good. Also, if macula of the retina is affected the prognosis is not favorable. In such cases low vision therapy may be needed. That is why an expert need to examine you or your kid as early as possible.
If you suspect your child may have amblyopia, Dr. Khanna can diagnose and treat this visual impairment. There are a number of advanced tests to be performed. These may not be available at your local eye doctor at Walmart or Costco.
How to Fix a Lazy Eye is a question often posed by young parents. Lazy Eye is a term used to define an eye that cannot see to its full potential. You may be aware normally an eye should see 20/20. That means that a person standing at 20 feet should see what a normal person sees at 20 feet. If a normal person can see at 40 feet what you see at 20 feet than your vision is 20/40. If after correction with glasses or contact lenses the vision does not improve to 20/20 than the eye is termed as Lazy. The medical nomenclature is Amblyopia.
Let us understand why an eye becomes lazy. The role of eye is transfer information from the surrounding universe to the brain. The eye condenses the light reflected from various objects on the macula. Electric signals generated are transferred to the brain by optic nerve. A specialized area of the brain called the occipital lobe converts these neuroelectric signals into vision.
Any flaw in this process leads to an Amblyopic or Lazy Eye. There are three types of Lazy Eye.
The first kind is Neurological. This occurs when there is an obstruction in the neurological pathway or the brain. If the optic nerve is not developed, or the conduction pathways are malformed the light is not transmitted to the grey matter. Also, the brain may be underdeveloped due to infections or genetic causes. This is the most challenging kind; currently this is not amenable to treatment.
The second kind is deprivation amblyopia. If the light is prevented from reaching the macula, it fails to stimulate the brain. There are various causes for this. Cornea may be opaque. There may be cataract in the lens. The jelly behind the lens may be fibrotic and hazy. The good news is that treatment can be provided. The earlier it is instituted the better the chance of fixing the lazy eye. Cataract procedure may have to be performed even before the baby is one year of age.
The third kind is refractive Amblyopia. The cause is nearsightedness, farsightedness or astigmatism. When the eye is very small or very large or has astigmatism significantly higher than the corresponding eye it is at risk of developing Amblyopia. Here the light reaches the macula and messages are delivered to the brain. But the messages are distorted. Since the brain keeps receiving information it has the best potential to recover.
How to Fix a Lazy Eye caused by Refractive Error
The way to do this is to fix the refractory error. The correct procedure would be influenced by the age and the refractive power. If the numbers are in the range of Lasik eye surgery this may be the simplest procedure. In such instances Lasik may even be performed on kids as young as six years. Sometimes an artificial lens may need to be implanted over the natural lens. If the person is above fifty years of age a presbyopic implant may be the best option.
Curing Lazy eyes is possible in expert surgical hands. Education about lazy eyes is important as it can cause learning disabilities in children. Lazy eye is also technically referred as Amblyopia.
Recently a mother and her daughter came to our office. They both said they had lazy eyes and previous doctors had said nothing could be done for them. In fact, the mom said her optometrist cautioned her that nobody should ever touch her eye. Well we changed that unnecessary caution into sight!
Lazy eye is an eye which is not working to its full potential. This is caused when an eye has a higher degree of prescription compared to the other eye. This may be because the eye is smaller causing farsightedness or longer leading to nearsightedness or asymmetric resulting in astigmatism. The image from this eye is not sharp and therefore the brain suppresses it. You may ask “what if the patient wore glasses or contact lenses?” and that’s a great question. The refractive defect is usually so much that with correction the image shape and/or size is markedly different leading to dissimilar images which cannot be superimposed by the brain.
This is different than a sleeping eye. In such circumstances the vision nerve called optic nerve or other components of the neuro visual pathway are not developed. Current technology cannot fix these problems, but we hope that future generations will be able to cure these issues.
We will restrict our discussion to lazy eyes caused by refractory errors. Let’s turn our attention to what has been the treatment modality for the last hundred years followed by looking at application of modern technology to fix this ailment. Traditionally the most common intervention has been to prescribe glasses and patching the “good eye” so the weak eye is forced to see. Kids hate it and get scared when they cannot see well out of the lazy eye. It is illogical to resort to patching without fixing the underlying problem. It’s like forcing a person to walk on a broken leg to make it stronger. We don’t do this do we? Instead we set the fracture and then start the rehabilitation.
We first perform a very detailed eye exam to determine the refractive state of the eye. We do scans of the cornea, nerve and macula to confirm they are normal. The treatment varies based on age but kids as young as eleven can have laser vision correction in a normal laser suite. Younger kids may need an anesthetist. If the prescription is way higher for laser vision correction than an implantable collamer lens may be employed. In patients older than forty-five, PIE or presbyopia implant in eye is used.
The sooner the eye is corrected the better the chances of equalizing the both eyes. Interestingly what older textbooks taught there is no cut off age to restore lazy eyes, however patients in their seventies have had lazy eye improved by our interventions. Once in a while we are even amazed to see the lazy eye overtake the good eye and become the stronger one.
If we do not intervene, the lazy eye can deviate out or in leading to squinting or strabismus. Before any squinting surgery is undertaken, the lazy eye should be fixed. Otherwise the eye may again move away.
In summary Refractive Amblyopia has the best chance of improving. This is possible in kids, young adults and even older individuals.