What is Amblyopia?
Amblyopia (or lazy eye) is where the eyesight in one eye is worse than in the other and that correcting the eyesight (with spectacles or contact lenses) does not improve the vision.
The three most common causes of Amblyopia are:
1. A large refractive error in one or both eyes.
2. Congenital cataracts.
3. An eye turn.
Generally the patient experiences no symptoms apart from the possible awareness of poor eyesight in that eye when they cover up the good eye.
1. Remove the cause of the amblyopia.
- Correct any refractive error with spectacles/contact lenses, remove any cataract or treat the eye turn.
- This may restore the eyesight without any further treatment required.
2. Start visual therapy
- Most people with amblyopia need visual therapy as well as treating the underlying cause. This is because the drop in eyesight is not because the eye cannot see. Once any refractive error is compensated the amblyopic eye will be receiving a clear normal image.
- The eyesight however may still be poor because the brain is still ignoring or suppressing the image from the amblyopic eye just like it did prior to treatment.
- Visual therapy, including patching the good eye, is undertaken to stimulate the brain to pay attention to the amblyopic eye.
- In reality amblyopia is not so much about the ‘lazy eye’ but rather the brain (visual cortex) having learnt to turn off (supress) the blurry picture from the amblyopic eye so that it does not interfere with the picture from the good eye.
Duration of treatment
- Age should not be a deterrent at any attempt to improve visual acuity. Research has shown that the younger we treat amblyopia the more likely we are to restore normal eyesight.
- There is not critical period as such, but rather it becomes more and more difficult to improve visual acuity as the child gets older.
- In those cases where the amblyopia is due to an eye turn, the amblyopia has to be treated before the eye turn can be treated.
- It takes between 3-6 months of visual therapy to achieve the above goals in most cases of amblyopia.
- The visual therapy will need to be monitored, and the patient reassessed in office, every 2-4 weeks.
- In severe cases of amblyopia, normal eyesight may not be fully achieved or will take a longer length of time.
- Once cured the spectacle correction may still be required to ensure the amblyopia does not return.
- If patching is required it need to be done for a minimum of 2 hours per day.
- Patching is not done at school but rather at home while doing assigned visual therapy activities.