Double vision during excercise

AlliSport Andy
AlliSport Andy Posts: 2
edited March 2012 in Health, fitness & training
I have recently started cycling again, and as I live in the Forest of Dean enjoy a wide choice of trails in the area. I try to go out twice a week and we try to push quite hard to make sure we are getting some benefit, fitness and technique - wise but I have a problem with my eyes that is now beginning to impact on my enjoyment of the activity.
Basically I am fine for a while but after a period of reasonable excersion, I find that I suffer from double vision.
I have made an effort to eat correctly, keep hydrated, carry sweets and energy drinks but to no avail.
I am 40 years old and have suffered from this for over 10 years. I used to play squash but had to stop as it became rather dangerous...
I have been to the opticians for eye tests, been to the doctors, seen a specialist at the hospital but no one seems to know what it is..... I am now wondering about continuing with the cycling as last week I missed a corner on the Verderers trail and crashed.....
Any help gratefully received!