Hi Helen,
I think it was Discovery Channel about a lady who was blind after an illness and she went sky diving, and while dropping to the ground her sight returned enough to see colours while falling down ,and this improved for her to see out of both eyes again after a short period.As she said, if I never gone sky diving I would be walking with a white stick still, while now I can do most things, not sure if it was the UK or not ? Perhaps it was blood pressure during the drop forced a blood vessel to open, and feed the optic nerve perhaps, allowing the optic signals to enter the brain again in a normal/restricted fashion ? Might be a cause to allow people with eye problems/blindness to sit in a barometric chamber while they reduce the pressure or increase it to see if changes occur in the eyes, I dont know what pressure changes would happen with a sky dive, increased pressure I imagine, NEVER get me doing it.