Exertion induced visual problem

Be very, VERY careful with this. I recommend a doctor visit at once. Here's why:

Two years ago I could have written this same post except substitute running for cycling and adda headache.

Hey, I'm tough, we're all endurance athletes, I'm going to brag on the forums about me going so hard it affected my vision... HTFU, Right?

I was having a stroke.

I permanently lost part of my visual field (uper left hand visual field in right eye, some in left eye) and suffered brain damage as a result. To this day remembering names of people is very difficult. No problems with anything else. Somewhat oddly, as is often the case with brain injuries, another area of my cognative ability (math) has become uncannily acute. The thing is, you don;t get to pick, and you may not survive- or worse. The BBC ran an interview conducted via a new technology with a "locked in" stroke survivor last week and it was chilling. Horrifying.

Moral: don't mess with this. Visual distortion is a very, very serious symptom. It may simply be mucus in your eye as you become dehydrated, but it may be the precursor of something much more serious. My stroke happened while I was running.

Get it checked out is my recommendation....

With anything in medicine, you want to make sure you are not having the "bad one". Rule it out first, and if it turns out it is just exercise related or an ocular migraine, then great.  When you call to make the appointment, they will triage you with a bunch of questions, and I would not be surprised if they have you come in much sooner than later.  I have sent patients to the ER immediately after seeing a small finding in the back of the eye.  Make the call! 

Somewhat parallel to Tom's experience, I started suffering ocular migraines as a symptom of a deteriorating aortic heart valve.  Eventually had open heart surgery to get a mechanical heart valve.

I hope it's nothing serious, but you definitely need to see your doctor.  Not something to ignore or take chances with.

Mark

Both, if it is something serious, your eye doc will refer you to your primary care/internist to get testing done. 

So what the doc say?

I went to the opthamologist who diagnosed me after a brief description only.  I'm thinking of going and having it checked out a little more closely now that I've established a pattern of it happening toward the end of hard workouts.

What was your nutrition like during or before these activities?

I can't say that I've experienced something exactly similar, but there has been a couple of instances where I was completing an long, intense workout and I didn't properly hydrate or bring along any nutrition/gels and towards the end my vision was "fuzzy" (I have always had good eye site). I wouldn't call it a loss of vision but more along the lines of light-headedness, low blood sugar type feeling you might get and associate with blacking out even though I didn't feel like I was blacking out (best way I can describe it). However, once I get some fluid and nutrition in me I was back to normal.

Just thought I'd share my experience, even if it's not similar. Hope everything checks out OK.

i vote for the ocular (sometimes called retinal or optical) migraine as well, although i certainly wouldn't hesitate to get checked out. i've had regular old nasty migraines for as long as i can remember, but about 3 weeks ago (after a particularly difficult workout) i was sitting in the parking lot at my son's school to pick him up and realized that my vision in one eye was "smeared". it was like someone had put a big thumbprint on my vision. took out my contact lens to make sure it didn't have something on it and that sort of thing, but nothing changed the blurriness. was worried about a retinal detachment so i called my eye doc and went in right away. nothing physically wrong with the eye at all, so based on my symptoms (blurriness, no pain, single sided) he told me it was probably an ocular migraine. turns out several folks that i know have had them as well. very disconcerting at first, but no permanent damage done. apparently the changes that cause the vision problems occur in the back part of the brain where vision is controlled, not in the eye itself. 

so that's my story. would still probably get it checked out or let someone know, but hopefully this is all you're dealing with. annoying but not dangerous. 

Better to do the tests and find nothing, then not to do the tests and miss something. 

Ten years ago I was having continuous headaches and some dizziness.  The GP chalked it up as a pinched nerve and gave me a script for a muscle relaxer.  I didn't use the muscle relaxer, but instead got an appointment with a neurologist.  Neuro sent me for an MRI and two days later I was having a brain tumor removed.  The tumor was benign, but due to the location (pressing up against the brain stem) the neurosurgeon said I would have likely died within a few weeks. 

Good luck and keep us posted.