Teenager with sudden, periodic loss of vision.

My 15 year old son is experiencing lower eye blackouts (he describes it as the "bottom half of his eye goes black) when getting up from a sitting position or out of a car, and total eye blackouts occasionally for a few seconds when just walking along.  He does have very bad eyesight and has worn glasses since he was six years old.
I have taken him to the neurologist who took blood (he fainted) and he said he could find nothing wrong.  He has never fainted before when he had a shot of any kind, but the doctor said it's nothing to worry about.  He also fainted the other day for no apparent reason.
I am very worried.  We live outside of New York City and I think I should take him into one of the hospitals there, but I don't know where to start.
Can you help me?

[Forum-OD-MP]

this sounds like "postural hypotension".  it is likely not an eye problem at all, it is a bloo pressure problem (specifically low blood pressure).

postural hypotension is generally not treated.  in extreme cases he could be put on low-blood pressure medication.

i dont know where you should go.  probably to your general physician...make sure and tell them you think he may be experiencing "postural hypotension"

[dvm508]

My 20-year-old daughter has reported something similar.  She has temporary bouts of blindness at any given time.  She describes it as a curtain that begins blacking out her vision in both eyes from the periphery, gradually closing in and then her vision "snapping back" very quickly.  She is very slender, 5' 7" and 110 lbs.  There are no headaches involved.  She does not remember a time when this didn't happen.  It has not occurred when she is driving but can happen anytime when she is walking.  Is this likely a blood pressure problem as well or an ocular migraine or.....?

[Ag-i-doc]

likely a blood pressure (low) or blood sugar (also low) problem.

[mamabuterfly]

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