I'm no doctor, but I don't think the nerves from the eye go through the spine. A disturbed blood flow seems more likely to me.

Anyway, I hope your first action was to make a appointment with a real doctor and then ask on ST.

It sounds like you have what is referred to as a V-pattern exotropia. Basically, when your head is down and your eyes are trying to look up, they have a difficult time staying straight and want to turn outwards. Add general fatigue in there and the symptoms will worsen. Your reference to double vision gives this away. As far as the blurred vision is concerned, any time you force your eyes to turn inwards, they focus. The prolonged focusing explains the blurred vision and the return to normalcy the next day.

Firstly, well done on staying upright despite your lack of vision!

As another ST'er commented, the nerves to the eye are cranial nerves as opposed to cervical nerves, so nothing going on in the neck will(shouldn't) influence your sight.

Whilst the above comment is the most likely cause, please do at least see your General Practitioner about this. I'm not saying you'll be whisked off to see a Neurologist but this is an incredibly unusual case, and I would hate for it to be an incredibly unusual trigger.

Good luck, and if you feel happy to, post the outcome on here so we can all learn!

Thanks.

Actually, this is not an unusual case at all. I am an optometrist and see a crap ton of binocular vision disorders. His explanation/case history fits perfectly with what I described.

Sure, if you want to go to a PCP (who will honestly have next to zero idea what is going on), go ahead. They will order a battery of unnecessary tests so they can bill your insurance and come up with a huge question mark as their final answer.

If you want the right answer, go see someone who specializes in eyes and binocular vision disorders.

https://www.outsideonline.com/...ody-during-100-miler

"Although very rare, according to a study in the journal Wilderness and Environmental Medicine, ultrarunners are susceptible to a “painless clouding of vision” that tends to occur beyond the 35-mile mark of some races. Researchers found that athletes who have had LASIK surgery are especially prone to in-competition optical irregularities. Fortunately, the authors note that these vision problems tend to resolve themselves within 3.5 hours of finishing.
While there is limited data on the causes of vision loss, Laye recommends wearing sunglasses, especially if you’ve had LASIK in the past. “The prevalence of these vision issues is far less in ultra-endurance athletes like cyclists or cross-country skiers who wear eye protection as a part of their sport.”
"

Can dizziness and an almost light headed feeling be a symptom of this also?

Absolutely. Have you ever seen double? It will definitely make someone dizzy and nauseated.

What treyedr is saying may be correct but I am also concerned about the other symptoms (along with the vision loss). As others have stated, the main nerve for the eye is the optic nerve, which is a cranial nerve. It connects directly from the brain to the back of the eye. The vertebrobasilar arterial system does run "up the neck" to the brain. Importantly, it helps supply bloodflow to the cerebellum and occipital lobe.

The cerebellum, having compromised blood flow, could lead to dizziness or light headed feeling. If blood flow is compromised to the occipital lobe (vision control center) then it can disturb the vision. Having your neck in this new position for a prolonged period of time could be causing a compression somewhere along that arterial chain, and that may be causing your current issues. As a young healthy athlete, I would not expect you to have stenosis of the vertebrobasilar system but I did know a heart surgeon (in his 40s) who did, so something to consider. Unfortunately, the only way to know is through an arteriogram. Now I am not a radiologist so there could be better ways to diagnose. Someone smarter than me would have to chime in.

Of course, I am simplifying this into layman's terms but you get the idea. Any time a patient presents with a problem, the doc's job is to come up with a list of possible causes. As treyedr advised, go see your eye doc first. Let that doc investigate but you may want to see if your PCP recommends further testing as well............as treyedr said, your PCP will know nothing about ocular disease so the purpose of that visit will be to figure out if it is a vascular issue or not

So you you had blurred vision and you were dizzy and cross-eyed yet continued your race.
Smart decision!

Not exactly the same but potentially similar: http://www.irunfar.com/...at-the-research.html

x2

Hindsight is 20/20.

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They constantly try to escape from the darkness outside and within
Dreaming of systems so perfect that no one will need to be good T.S. Eliot

I experienced similar results when i got 1) a more aggressive aero position, 2) a helmet with visor- i would train 5+ hr rides looking up thru my eyelids whilst wearing contacts would make my vision irregular at times if my eyes got dry. I changed my position slightly less aggressive and its been a non issue.

Look into ocular migraines. Yours seem to last longer then normal for one but its just an idea. I would follow up with your family doctor about it though.

Very astute feedback, everybody.
I really appreciate the thoughtful responses and intelligent context

I have had LASIK in the past.
The blurring was definitely emanating from the outer edges.
And it was starting to retreat before I feel asleep a few hours later.

So I will check with my local eye doctor and LASIK surgeon and follow up here if I learn anything that can benefit the forum.

Hello HankRearden and All,

I am hoping that you will learn more from your medical exams and doctor.

No fun getting weird stuff like that.

Playing Sherlock Holmes ....

Trying this experiment may shed light on your condition. (Should someone come in the room and ask what you are doing .... tell them to 'go away .... I am a triathlete' .... 'you would not understand' ...... and have some water bottles and Gu packets handy)

1. Sit up to a table (in a comfortable chair) and get adjusted so you are in your aero position (wear your helmet) .... rather than eyes looking forward as when riding .... relax your eyes and look at the table .... stay aero with neck stressed holding head position ..... perhaps a book to read and pass the time .... 5:27:32.

When the T2 time is reached .... observe and note any ill effects or Shermer's Neck Syndrome.

Allow a couple of days or more until completely recovered .... then ....

2. Same position and conditions as #1 except this time roll your eyeballs up to look forward as when riding .... maybe set up the TV so you can watch but plan in keeping your neck, head, and eyes as when riding in the aero position .... do this for 5:27:32.

Observe and note any ill effects or eye muscles twitching from constantly holding your eyeballs up to look forward.

If ill effects noted and eyeballs are twitching get one of these (below) for a cure ... to relax your neck muscles and your eye muscles when in the aero position.

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Cheers, Neal

+1 mph Faster

I had that happen to me at IMAZ ..double vision, blurry starting halfway through my he second loop of bike.
I'd never had it before nor have I had it since. I figured it was dehydration or whatever that stuff was coming out of the stacks along the bike route.

The one thing that oocurs to me is that the lower position causes you to rotate yours eyes further up into your skull than you have ever naturally done before. Make sure your doctor u derby ands the stupid lengths you have gone through to reduce CdA.

This is one component of the 7 steps to proper positioning for speed skating. The Long distance skaters in Belgium may have experienced these problems before, but they probably just stand up and reduce the eye stain issues.

Don't you fricken hate that about the IM distance? Despite all the prep, and doing the same distances of the individual sports essentially once every week for months, something unexpected and usually bad always happens on race day?

Anyway you finished and didn't crash or otherwise ended up in medical. Good job. The explanation provided by treyedr is probably what you were looking for.

Brilliantly said :) I would not go to my PCP for this (I am an ER doctor). If I went to anyone it would be an ophthalmologist/optometrist, with consideration for neuro eval too. Funny thing, I had crazy vision issues while doing Leadville 100 MTB this year. Attributed it to combination of high altitude, lots of bouncing on some of then descents, and repetitive transitioning of eye focus directly in front of me and then farther ahead, over and over. Resolved after all the bumpy parts. Definitely not a position issue there.

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Colorado Triathlon Company, CO2UT 2021, Crooked Gravel 2022, Steamboat Gravel 2022

You should check out the link above someone referenced for a discussion on irunfar.com. The discussion is more for ultrarunners but your case may be similar since you were doing a long endurance event at altitude. The short answer to the vision problems, during these events, is no one really knows what causes it. The purpose of the irunfar discussion is to put smart heads together and figure out the etiology

Hello, I am a Neuroradiologist. I very much doubt that your issue is vascular in etiology. You can pretty much turn your neck in any direction and you are not going to lose blood flow to the brain. We have two pathways to the brain, an anterior and posterior circulation, and they communicate with each other unless you have an anatomic variation. Even if you do have that anatomic variation, squeezing off your posterior circulation is essentially impossible to do simply by turning your neck. If you had a dissection and were throwing blood clots, you would almost certainly have permanent symptoms. I doubt this happened. It sounds to me like you bonked, and your bike position was unrelated. However, that is just an opinion and without doing a complete history and physical exam, internet medical opinions are close to worthless. If it happens again during a race, just stop and then go see a neurologist. More than likely this was just a one-off episode.

Glad you chimed in. As you said, I doubt it is an episode of throwing off blood clots. He mentioned he was "hyper-fueling" so that's why it seemed odd for this to be a case of bonking, unless he had been way behind on fueling and was cramming to catch up. It is just weird it happened with prolonged change in the neck flexion and/or extension (no way of knowing unless a pic or better description is provided) during the ride

I sometimes get blurry vision or basically lose useful sight from one eye or the other when I do long endurance events. Have spoken to various opthamologists about this for more than 5 years now. They first check for diabetes. No, I am not diabetes. The consensus seems to be that my corneas must swell sometimes after hours of exercise and that is what causes my vision to go. Would be difficult, if not impossible, for me to read or drive after most of my Ironmans.