Do you know where your blind spot is?

[Fred W]

No, I'm not talking about the one over your shoulder when you are riding.

We all have two giant blind spots right in front of us. Don't believe me?

Position your face about 2 feet from your monitor, directly in front of the below picture.

Now close your right eye and stare intently at the white circle. Move your head closer or further from the monitor and watch what happens to the plus sign.

Alternately close your left eye and stare at the plus sign, move in and out and watch what happens to the big circle.

The disappearing phenomenon is caused by the void in the retina's light receptors directly over where the optic nerve is located. Luckily we have binocular vision and only one eye needs to see something for your brain to appreciate its presence.

Puts a little fear into the idea of being a one eyed motorcyclist though, doesn't it?

 

[El Toro Joe]

So...what's supposed to happen?

 

[Fred W]

Stare (fixate) harder, or try different distances from the monitor depending on how large your monitor is.

The object that you aren't staring at disappears once your brain forgets it was there when it is in your blind spot.

 

[rushes]

So...what's supposed to happen?

Waiting also....

I've only got 2 brain cells to work with, but neither forgets anything... That I can remember....

 

[John d]

Both my brains cells work most of time, but I can't get one of those things to disappear. I'll try later after a few shots of Whiskey, maybe both will disappear.

 

[TomInPA]

Definitely had the + disappear, but not the circle. I'm aware of the optical nerve blind spot and keeping your head on a swivel is the way to overcome that hopefully.

 

[Bugnatr]

Worked for me but now I'm crossed eyed

Perhaps I can blame all the stuff I misplace on my blind spot.

.

 

[FJRay]

Worked for me but now I'm crossed eyed:uhoh: :uhoh:
Perhaps I can blame all the stuff I misplace on my blind spot.

.

Or maybe age!!

 

[Fred W]

Definitely had the + disappear, but not the circle. I'm aware of the optical nerve blind spot and keeping your head on a swivel is the way to overcome that hopefully.

+1 - Now if we could just convince those cage drivers to do the same...

I wonder how many of the times when after pulling out in front of a rider, and the driver claims "I just didn't see him", that they were glancing sideways for whatever reason only one eye was in play, and the bike was in that blind spot?

Something to think about...

 

[LCB]

According to my kids, it's about 3 inches past the end of my nose.

 

[Fred W]

Kids...

You can't live with 'em, and you can't eat 'em.

 

[ionbeam]

I wonder how many of the times when after pulling out in front of a rider, and the driver claims "I just didn't see him", that they were glancing sideways for whatever reason only one eye was in play, and the bike was in that blind spot?

To add to this a bit, a senior driver in our family was judged by everyone to have a driving problem so he was run through a Supplemental Driving Performance Evaluation. One thing he failed was something we didn't expect, it is a measure of refocusing. This is the time it takes the driver looking at one object to the next to cognitively refocus. They timed the driver from looking straight ahead, to looking to the left 90º, see an object placed there then timed him when he looked forward again and refocused. This cognitive refocus includes optical refocus. In the case of this senior driver the cognitive refocus time was 10-15 seconds. The driver could turn his head, glance to the left then back forward too quickly to refocus on what was coming from the left. This means that even though the driver looked to the left he probably wouldn't have seen anything unless he dwelled his attention for nearly 10 seconds.

His right to drive was revoked. He found a doctor that got his license reinstated. They are out there, protect yourself at all times.

 

[Fred W]

That is interesting (the part about re-focusing delays, not the reinstatement of driving privileges)

There is another completely normal vision phenomenon called "Saccadic Suppression". A saccades is when you quickly move your eyes from one point of focus to another. Our brains suppress the incoming visual stimulus that occurs during the saccades so the brain doesn't get bogged down processing what would just be blurriness.

By the way, when you are reading these words your eyes are doing a series of small saccades.

You can test the suppression by staring at yourself in a close mirror. First focus on one of your eyes and then quickly shift your focus to the other one. See if you can catch your eyes moving (you can't due to saccadic suppression). Someone else watching you in the mirror can see your eyes move, but you cannot. OTOH if you use a webcam on your PC and try the same thing you will be able to see your eyes move because of the slight time delay in processing the camera video to the monitor.

I wonder how losing saccadic suppression would impact your ability to quickly refocus?

 

[BigOgre]

Some time ago (damn it goes fast!) I watched the Rolex 24 which included Earnhardt Sr. racing. Of course that team got a ton of TV coverage and I listened to one commentator during the night speculate on how much longer he could go on racing. Spoke of how it was common knowledge that age robs not only your vision but your ability to recognize and react. I remember wondering if this guy could be speaking the truth. I mean this was Dale and no one could question his driving abilities. And besides, he had to be still in his 40's! I never researched it or anything but it has stayed with me and is something I think about regularly, especially while riding and especially since I'm older now than he was then.

 

[ionbeam]

....age robs not only your vision but your ability to recognize and react....I think about regularly, especially while riding and especially since I'm older now than he was then.

And I think about it, especially while riding because I'm significantly older than you

Since learning about some of the senior driving limitations I have been trying to assess how I'm doing. It scares me that I can see the beginning of sensory and cognitive decline in my riding, it's not much but enough that it is causing me to change some things I do. For some reason, at night my sensory and cognitive decline suddenly gets much worse.

 

[infrared]

....age robs not only your vision but your ability to recognize and react....I think about regularly, especially while riding and especially since I'm older now than he was then.

And I think about it, especially while riding because I'm significantly older than you

Since learning about some of the senior driving limitations I have been trying to assess how I'm doing. It scares me that I can see the beginning of sensory and cognitive decline in my riding, it's not much but enough that it is causing me to change some things I do. For some reason, at night my sensory and cognitive decline suddenly gets much worse.

Ionbeam,

Night drivers (especially riders) need to be aware of "night blindness." Like color blindness, it can be a fairly minor problem, or severe. This problem can be caused by a lack of Vitamin A in the diet, or by a medical condition that prevents a good uptake of Vitamin A by the body, even when there is enough Vitamin A available in the diet. This condition is not caused by "old age" and usually it responds well to corrective actions. A multivitamin per day can be enough to fix the problem, but if not, a doctor visit may be the right option.

Fatigue (mental and physical) may also be a factor in driving at night. "Getting there" (what a pilot might call "get-home-itis") is not the mission here; getting home in one piece should be the priority, even if that means a rest stop, until the morning. I've reached an age where I may fight my limitations, but only to a certain point, which is not "what I could do at age 20."

Cheers,

Infrared

 

[Fred W]

I think maybe ionbeam was slyly alluding to that scotch in his glass (in the picture) possibly being responsible for some of his night time cognitive decline.

MEM, on the other hand, is convinced it is the cigar's fault. Yamafitter (usually) has the good sense to stay seated in such conditions.

Say... Does Vitamin A help with hangovers too?

 

[HotRodZilla]

I think maybe ionbeam was slyly alluding to that scotch in his glass (in the picture) possibly being responsible for some of his night time cognitive decline.
MEM, on the other hand, is convinced it is the cigar's fault. Yamafitter (usually) has the good sense to stay seated in such conditions.

Say... Does Vitamin A help with hangovers too?

:tonguesmiley:

No, but a good Saline IV does.

All I gotta say about this is, getting old sucks. I'm not even there yet, but what I see concerns me a little.

 

[LCB]

Be afraid... be very afraid.