Hi,
Thanks for writing in.
The chances are that your son has suffered a stroke which resulted in loss of vision in one eye along with headache.
It is very important that he takes adequate rest. If the test results confirm a stroke you will need to consult a neurologist for him.
He will be given medications to dissolve the clot in the brain. If there are any risk factors present like high BP, diabetes, high cholesterol, obesity, smoking etc they will have to be brought under control.
Hope this helps!
The liklihood is your son had a "stroke".
Essentially a clot that blocked a blood vessel leading to the optic nerve. The outlook for recovery is not good. It's possible, not a high probability event. In this case the window of opportunity to prevent loss of sight is very small.
Such strokes can be caused by simple dehydration.
It appears the hospital has been performing competently, doing tests and giving an MRI.
You need the advice of the neurologist who is treating him at the hospital.
Sometimes these are isolated events which will not happen again, and sometimes there is an underlying problem requiring life-long medication.
Keep his physician informed of his progress.
They seem to be paying attention and looking out for his interests.