Lazy Eye Amblyopia Treatment
Lazy eye is a condition in which one or both eyes have decreased vision caused by visual deprivation or abnormal binocular fusion.
The lazy eye develops in early childhood; hence it is a disease of childhood. Once a lazy eye has developed it becomes almost impossible to reverse the condition in some cases, while timely recognition of the lazy eye by the parents of the child can give a good prognosis for the vision.
As no organic cause can be determined by the examination, that is the reason why lazy eye disease remains undetected until late. There are some therapeutic procedures when followed in children can result in the best visual results. However, compliance is a keep factor for the best results.
As the process of normalization is prolonged, many patients do not keep compliance which is a key factor in a poor outcome. Education of the parents is very important who is having a child with lazy eye or amblyopia.
CLASSIFICATION OF LAZY EYE:
The causes of amblyopia can be divided as followed
Stimulus deprivation amblyopia:
One of the most common causes of stimulus deprivation is congenital cataract, especially unilateral cataract is highly amblyogenic. Other common cause includes drooping of the upper lid up to the visual axis of the eye.
Constant occlusion of one eye (> 1 week per year of age) due to any cause is very likely to develop amblyopia.
This condition arises when the refractive power between the two eye is >1D. This is a highly amblyogenic stimulus.
When the symmetrical refractive error is >+5.0 DS or > -10.0 DS unilateral amblyopia may occur if correction is not done.
Astigmatic/ meridional amblyopia:
The relative risk of astigmatic amblyopic is increased if cylinder power is > 0.75 DC. Risk is more when there is a difference in axis or if the magnitude between two eyes is different.
Strabismic amblyopia is caused when one eye is preferred for fixation. If the process is alternating between the two eyes, then the risk is low.
Pathophysiology of Lazy Eye:
There is a reduction in the spatial resolving power of the retinal cells.
Lateral geniculate nucleus:
In lazy eye there is reduction number of cells of all the six layers of the lateral geniculate nucleus.
There is reduction in the number of cortical cells.
Clinical Features of Lazy eye:
- Decreased visual acuity of two more lines on the Snellen chart.
- Crowding phenomenon:
There is an abnormality of contour interaction between the point of fixation and the adjacent objects. Visual acuity is better for single optotypes than multiple optotypes.
- Normal ocular examination.
- Decreased contrast sensitivity.
- Binocular suppression of amblyopic eye.
MANAGEMENT OF LAZY EYE:
Exclude other causes:
Other causes of decreased vision such as refractive error, cataract, tumors should be excluded.
Remove obstacles to clear vision:
Remove refractive error and perform cataract surgery for cataracts.
How Long Does it Take to Fixing a Lazy Eye With an Eye Patch
Occlusion therapy (GOLD STANDARD):
The amount of occlusion therapy depends on the age, severity, and cause of lazy eye.
- Patching should be started as soon lazy eye is detected.
- For part-time occlusion, it depends on the age of the patient. 1 hour/day for each year of age.
- Full-time occlusion should not exceed 1 week per year of age.
- Patching should be continued for 3-6 months.
- If there is no progress for consecutive 3 months, patching should be considered as a failure.
- Patching should be maintained up to the age of 9 years, which is labelled as age of matured visual system.
This method is preserved for non-compliant or patients who show a failure to patching therapy
1% atropine drop is placed in the better eye to blur the vision for near.
Image degradation is made in the better eye so that amblyopic has a competitive advantage.
In this method under correction of the better eye is made with optical lenses.
ADDITIONAL MANAGEMENT PRINCIPLES:
- Strabismic amblyopia:
- Occlusion therapy should be started before strabismus surgery. It is done because the fixation behavior will be harder to determine once the strabismic correction is made.
- Parent motivation towards patching be increased by visual reminder of strabismus.
- Amblyopia due to refractive error.
- Refractive correction is made before patching therapy.
- Part-time occlusion is preferable if binocular interaction is present, amblyopia is mild and the child is in school.
- Stimulus deprivation amblyopia.
- Remove any barrier within first 6 weeks of life.
- Awareness and education of the primary care physician.
- Vision screening programs in all communities.
- Red reflex of every baby should be checked at birth.
Can a Lazy eye be reversed?
Amblyopia can be reversed up to the age of 7-8 years, after this age it is usually permanent. It is the average age for the development of normal vision in the human eye, after this, no therapy or treatment can reverse the vision.
What are the signs of amblyopia?
The signs of amblyopia include
- Trouble seeing near or distant target
- Inward or outward deviation of the eye
- Head tilting
What age does a lazy eye develop?
Up to 6 years of age children are vulnerable to develop amblyopia.
What if there is no response after 3 months of Patching therapy for children?
If there is no improvement after 3 months, then consider the following
- Wrong diagnosis
- Uncorrected refractive error
- Failure to prescribe specific treatment
- Irreversible amblyopia
How to fix a lazy eye: Treatment
In children below the age of 9 years, patching therapy is considered a gold standard. It will force the lazy eye to do it function more effectively while the patch is placed on the better eye.
Can lazy eye worsen?
If left untreated the lazy may get worsen over time. The brain gradually stops to pick signals from the lazy eye and it can render as a blind eye.
How to fix a lazy eye in adults
Until now there is no treatment option for the correction of lazy eye in adults. The only possibility that can be provided is the optical correction to the best of its level.