Landing with one eye

[billvon 2,384]

A few months ago I posted about how depth perception wasn't too affected by having two eyes (parallax is just one way we perceive depth, and doesn't work past 5-10 meters) and thus skydiving and landing with one eye shouldn't be that hard. A friend of mine called me on it, and last weekend I tested my theory. I taped over half my goggles and made a jump. I didn't have anyone to jump with so I just did a solo.

Freefall was no different. I opened around 3000. The first thing I noticed was that it was a lot harder to clear my airspace - I had to look around a lot more and I tended to want to turn left (since I could see that way better.) It was really distracting on final since I had to keep looking hard right to make sure I was clear over there. No problems flaring; I didn't notice any lack of cues of when to flare. I was jumping a Silhouette 170 loaded about 1.2 to 1.

So I had no problems with depth perception, but I did have problems just seeing enough, which I hadn't considered before the jump. I may try doing RW one of these days the same way to see if being closer (2-4 feet) makes the lack of parallax more noticeable.

[gus 1]

I met a guy once who was pretty much blind in one eye. He had alot of trouble flaring, had the odd biffed landing and eventually broke a leg (or maybe two). Do you think the ease with which you landed with one eye could be down to the number of times you've done it with two?

Gus

OutpatientsOnline.com

[skycat 0]

There is/was (not sure if he is still there) a guy in Houston that as a child was shot in the eye with a beebee gun. He said it doesn't affect him at all because it has always been like that, and he doesn't know any different.

He is a freeflier, swooper, TM-I, and BASE jumper.

Fly it like you stole it!

[lukepinion 0]

Isn't it true though that if you are blind in one eye you have know depth perception. I work as an Optician and when i give the depht perception test to patients with vision in only one eye, no one has ever been able to see even the easiest circle.

Luke

[skycat 0]

I have no idea, as I'm not blind in one eye. All I was saying is that there was one guy who didn't have any problems with being blind in one eye.

My mom was also blind in one eye or I think it was more like 90%, she didn't seem to have any issues with day to day stuff, she never tried skydiving, but driving and such wasn't an issue.

Now I doubt I could go from 100% vision in 2 eyes to 100% in 1 and 0% in the other. My brain hasn't learned how to compensate.

Fly it like you stole it!

[billvon 2,384]

>Isn't it true though that if you are blind in one eye you have know
>depth perception.

No. Both in theory and in practice, people with one working eye can judge depth.

The theory:

Parallax, or how much your eyes cross when you look at something, is what you gain from use of two eyes, but is only one of the mechanisms we use to judge distance. The other physiological distance cue is focal accomodation; you contract or expand your lens to focus on far vs near things, and that works with one eye or two. Both of these only work with very close objects, inside about 10 meters.

The other cues are perceptual. Perceived motion is a big one, and it's a problem all students have to get over (it looks like you accelerate when you get close to the ground because you're closer.) Other cues:

Occlusion (near things cover far things)
Relative motion (things behind your focus move one way, things in front move the other)
Relative size (far away things look smaller)
Visual parallax (parallel lines converge far away)
Atmospheric degradation (things far away are hazy)

In practice, people with one eye can fly airplanes, drive cars, play baseball, and skydive with little problem; they would have a lot of problems doing those things if they had no depth perception.

[lukepinion 0]

Thanks for clearing that up for me!

[JumpHog 0]

As someone who has very poor vision without corrective lenses, I can throw some insight on this. For most of last year, I wore contact lenses. On about 20 jumps throughout the season, I had a contact lens pop out in freefall. Although it was a minor inconvenience, I did notice that it was significantly tougher to judge distance. My videos would be farther from the subject than normal, and I would usually plane out too high form a front-riser dive. Down-low it didn't make as much as a differnece, as we usually use multiple cues to judge height, such as the objects around us. Even on my itty-bity canopy, I never 'biffed' a landing due to a lost lens, but it definately made landing a bit tougher. Now I've swicthed back to eyeglasses and plan on getting laser-correction sugery, so that I never have the problem again.

[Iflyme 0]

Interesting ... I have very poor vision from my left eye, due to a head injury when I was a child. I have reduced depth perception, but as I have lived like this for 3 decades, I often forget about it for months at a time. I think you work with what you have. But now you've got me wondering how this affects me when I have to dive down to join a base falling below me ... hmmmm. Interesting topic!

[Brains 2]

I know that sometimes when i am driving home from the dz, i drive better with one eye closed

Never look down on someone, unless they are going down on you.

[sunshine 2]

As someone that only sees with one eye, i can tell you it does affect depth perception. There is no way someone who has thousands of jumps can just cover one eye and get the same effect.

___________________________________________
meow

I get a Mike hug! I get a Mike hug!

[rigging65 0]

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As someone that only sees with one eye, i can tell you it does affect depth perception. There is no way someone who has thousands of jumps can just cover one eye and get the same effect.

I think this makes alot of sense. I have sensitive eyes to the point that I don't wear anything on front of them when I land. I have excellent vision, but I really have troubles if I leave my glasses on during landing...and they're not cheap lenses, so it's not that.

Now, granting that I fly a fast moving HP canopy, perhaps the sensation of very rapid movement is more than my tiny brain can calculate if the data isn't coming in perfect. Also, I'm sure you'd get better with practice as the body would most likely adapt to the change over time. I'm not about to go and try this loaded at 2.1 though

"...and once you had tasted flight, you will walk the earth with your eyes turned skyward.
For there you have been, and there you long to return..."

[Jimbo 0]

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A friend of mine called me on it, and last weekend I tested my theory....

So I had no problems with depth perception, but I did have problems just seeing enough, which I hadn't considered before the jump.

Is it possible that you felt depth perception wasn't a problem because you were jumping a fairly big and docile canopy? Would you be willing to try the same experiment on your Safire?

-
Jim

"Like" - The modern day comma
Good bye, my friends. You are missed.

[billvon 2,384]

>Is it possible that you felt depth perception wasn't a problem
> because you were jumping a fairly big and docile canopy? Would you
> be willing to try the same experiment on your Safire?

Sure, under decent conditions (i.e. I don't want to repeat the downwinder at Elsinore last weekend under the 119 with one eye.) I will have to try to find someone to do a 2-way with as well.

[quade 3]

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I will have to try to find someone to do a 2-way with as well.

Come on up to Perris and do 2-way drills with Lori Thomas. She has been sight limited for quite awhile so it'd be interesting to see who would do better.

As for the test being fair with you jumping a canopy loaded at 1.2:1 -- it'll be interesting to see what Lori has to say about that as well. I -think- that's pretty close to what she's jumping.

About the only other test that I can think of would be to cover the other eye and see how well you do. Different parts of the brain get processed differently and you may have picked the "easy" side for you. Sight limited individuals almost never get to pick.

quade -
The World's Most Boring Skydiver

[voodew1 0]

I also find that driving home from the DZ with one eye covered helps me also!

The pimp hand is powdered up ... say something stupid

[hooked 0]

Interesting........I don't have correctable vision in my right eye and I rely on my left for most of my vision. I never even thought that it might pose a problem. Not having to land yet, on my own....I'm wondering if it will be a problem, or if I am so use to my vision the way it is, it won't matter.
J

--------------------------------------
Sometimes we're just being Humans.....But we're always Human Beings.

[drenaline 0]

Just a thought for a good investigation:

try everything again but with the other eye.

HISPA 21
www.panamafreefall.com

[quade 3]

Is there an echo in here?

quade -
The World's Most Boring Skydiver

[jbrasher 0]

I've been blind in on eye since birth and the only thing I have a problem with are the optical illusions that require you're brain to merge 2 pictures into one.

I've been jumping for more than 30 years and done many night demos without any problems from depth perception; (the problems are usually from other things , but that's another story.

I've heard that if our eyes were further apart are depth perception would be better but that once you get beyond about 6' you aren't using 'depth perception' so much as experience.
Hence your discomfort, Bill. Maybe you need to do about 6 months worth of jumps with one eye.

Red, White and Blue Skies,

John T. Brasher D-5166

[drenaline 0]

echo and laziness to read all the posts. Sorry bro

HISPA 21
www.panamafreefall.com

[ltdiver 3]

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As someone that only sees with one eye, i can tell you it does affect depth perception. There is no way someone who has thousands of jumps can just cover one eye and get the same effect.

Thanks, sister! We should meet up sometime and jump! Are you coming to our Perris dz.com boogie in May?
ltdiver

Don't tell me the sky's the limit when there are footprints on the moon

[ltdiver 3]

You took up the challenge, Bill! You're da man! Interesting, huh!

Ahemm....(clears throat)...

However, I have to disagree with some of the posts here.
1) I load my canopy at 1.41:1. (sometimes more if I have a fast 4-way to film.)
2) Which eye did you cover? I don't see out of my left (thus the 'artistic-visual' side of the brain isn't in full mode).

You -are- correct about doing RW work in any form, however. It is different. 1/2 your visual field is gone. Plus, you really feel that you are closer than you are. And if you reach for a grip (and you are farther away) you will backslide away.

The visual thing on landing, however...if you are supposed to look at the horizon, not the ground (which is where you get your paralax and visual sharper focus from), then 'depth' in this fashion is lost.

I -know- that a canopy that glides over the ground, as you land (i.e. more often a 9-cell, tapered canopy), makes landing a heck of a lot easier. A canopy that dives more than planes out gives me heck. The time to judge 'depth' is lost.

We've done a couple of skydives, you, Amy, and I. Notice anything different from those? I'd love to take you up for a few trial runs with your left eye covered, then your right one. It -is- interesting.

And like driving a car, you have your head on a swivel the entire time. I really judge my timing when changing lanes, et al. I watch the traffic pattern in my rear view mirror to see when a lane is clear, check my side mirror, then turn my entire body to look and check the lane as well before I change lanes.

Do a little experiment for me. On a day you can, tape over one of your eyes (you can choose), go through about 4 hours of life.
1) Try pouring a drink in a glass. How far up to the rim do you go before stopping (the first time)?
2) Pick something up from a table, walk away with it, and set it down somewhere else.
3) Drive your car around the block and see (or not) what view you're missing. Parallel park!
4) Have Amy take a picture of you and what posture your head tends to be when looking at her.
5) Play ball (tennis, catch -and- throw a ball, hit a baseball with a bat, etc). You'll see exactly what depth perception is like. I mean, try something that you're not as familiar with as landing. These were all very interesting discoveries when I tried to return to the sports I loved. (however, in Archery, I just got better! :^) )

Your scientific quotes on depth perception are right on, Bill. However, in practical use they fall a bit short in some endevours.

btw, what's the most expensive skydive you've ever had? Mine racked up to be over $1,000 one jump. I'm still waiting for the wuffo to come up to my eye somewhere in the dirt and scream!

ltdiver

Don't tell me the sky's the limit when there are footprints on the moon

[Iflyme 0]

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the only thing I have a problem with are the optical illusions that require you're brain to merge 2 pictures into one.

At first I wondered why I couldn't see those darn things ... then I remembered the old' bad eye ... it's the same with 3D photos when you wear the funky blue/red glasses -- never works for me. But in general, I actually above average vision. Guess the good eye compesates for the bad one.

[ltdiver 3]

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As for the test being fair with you jumping a canopy loaded at 1.2:1 -- it'll be interesting to see what Lori has to say about that as well. I -think- that's pretty close to what she's jumping.

Nope. Loading my canopy at 1.41:1 now. Thanksgiving, Christmas, and New Years agreed with me. My patients (and vendors) love me! They keep bringing gifts of food and goodies!

Man, I love my job!
ltdiver
PS Yeah, wish I got to pick and change eyes once in awhile. You know, the interesting 3D picture craze came about -just- after I lost my eye....so I never got to enjoy staring at and eventually seeing what others discovered. I tried! I stared at the picture until my eyes watered, but no....3D pictures on the wall are not for monocular ppl. (sigh)...

Don't tell me the sky's the limit when there are footprints on the moon