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Monocular vision


Geoff_H
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At present CASA does not appear to allow a Class 2 medical for monocular vision without correction.  I believe that it is possible to get a Class 2 without correction if a suitable medical professional approved it.  I have monocular vision, by choice. Upon replacement of lenses for cataract correction, I have a vision range from 150mm to infinity.  I do not have vision correction for all aspects of life.  Including 3D movies, the most surprising thing for me.  Distance measurement is 80% of normal vision, I can still thread a needle without correction.  Although not in focus in my left eye it is still used by my brain for distance use.  

My question is does anyone know of a way that I can get a medical exemption, similar to the USA exemption? I am starting to do aerobatics so I want the Class 2 med.  

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I was too chicken to go for " no more glasses" My understanding was that you make one eye for close-up and one for distance, and the brain learns how to cope. Is this correct?

I thought if there was a brain which couldn't cope, it would be mine and anyway I am used to using reading glasses, so I opted for 2 eyes of long sight.

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Near infinity but short of, is best you can see to about 6'' and just need  1.5 -2.0 magnifiers to read or close up stuff. Those that recommend different for each eye don't really understand what that will cause.  Nev

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My definition of monocular is one eye only and I know some one eyed pilots.Or are you talking about something else such as different focussing caused by cataract surgery?

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My comment is related to having different focal length fixed lenses in each eye with cataract surgery.  You can't focus after that unless you get special lenses which have a higher failure rate. Nev

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I think that the correct term is monocular as theoretically only one eye is being used at a time.  However the reality is that both are usually being used.  They are lenses the same as every person gets for cataract replacement.

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I think that the problem that I have with CASA is that it is perceived that i cannot judge distances with monocular vision.  However this is not absolutely true. When trying to judge distances at very short range, around 6 inches, yes I have difficulty, th thread a needle by holding the needle axially, then it's just a matter of up down sideways movement.  But catching a ball is no problem.  Although my left eye is not in focus it is still used by the brain.  The brain detects the the centre of the fuzzy ball and uses this and the infocus eye for distance perception.  I am around 90% of before eye operation effectiveness.  How I see 3D movies is still a wonder.

My optometrist, unhappy that I am not buying glasses anymore, said that I could not catch a ball with this vision.  It seems that this is a widely held misconception.  I expect that this is why CASA believe that I need eye correction when flying.  From what I read of USA situation is that if an eye specialist says that it is not restricting you you can get an exemption to needing eye correction.  How do I get thos exemption in Aus.  Do I go to politicians, eye specialists?  Any and all ideas welcome! Geoff

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No lenses supplied here....  anyway, I use the 1.5 magnifiers from the cheapo shop. They used to cost me 3.99 dollars. Probably gone up now.

BUT the cataracts were done by a good guy and now I can see the leaves in the trees and other planes in the sky. Best operation ever.

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the 2 ways the brain measures distance are 1: apparent size and 2: angle of cross-eyes.

The second one is what you use with really close things. Try playing table-tennis with one eye wearing a patch and you will get an education.

I reckon that you have both these things in operation Geoff, and that is why you can catch a ball, which would be similar to table-tennis.

Flying, even landing, uses the first method and you sure have that too.

Your CASA types need more education. Keep on with what you are doing.

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People who've only ever had one eye seem better at distance assessing than if it's a recent change. I had a student in my early days of Instructing who only had one eye and he would consistently fly into the ground with some disturbing results. I couldn't see how that would be overcome but these days they may have better means of testing depth perception... Nev

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Once, many years ago, I played table tennis ( B grade) for the kangaroo flat club. Gosh I was surprised at how I missed the ball when wearing an eye-patch.  Otherwise, it was hard  to tell the difference.

I reckon your student may have had an additional  problem  Nev,  not that there is anything you could have done about it. Landing does not use the cross-eye angle  as much as the "apparent size" method.

Mind you, I have never had a one-eyed student, only a passenger once who I tried ( unsuccessfully ) to get to join the club. I was mainly concerned if his field of vision was too small, you would need to move your head even more I thought. Sorry but I never thought to wonder if he could land ok.

 

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He was quite young and seemed to cope with most things in normal life. I like to think I don't scare easily, but he'd just not flare. We put in a fair bit of time and no improvement so the cost became a factor with no progress being evident. I know that people who  are long time with one eye do better. I certainly don't go around corners on a motorbike well with one eye closed. There should be some research available by now I would think.  Nev

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On 25/11/2022 at 7:51 PM, Bruce Tuncks said:

No lenses supplied here....  anyway, I use the 1.5 magnifiers from the cheapo shop. They used to cost me 3.99 dollars. Probably gone up now.

BUT the cataracts were done by a good guy and now I can see the leaves in the trees and other planes in the sky. Best operation ever.

this post makes me wonder if what is being discussed here could have been a factor in the glider collision a couple of weeks back.

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Once, I was taking a hang-glider guy for a passenger flight in  glider. On tow, I let him have a go on the controls cos he seemed so good. In my recollection, I only took my eyes off the tug for a second to look around for other gliders etc. When I looked back, NO TUG! in panic, I looked around to find we ( the glider and tug ) were formating wing-tip to wing-tip. ( about 1500 ft ).

I sure learned a hard lesson from that... you never assume too much I learned.

But was not that glider collision the result of them entering cloud?

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31 minutes ago, Bruce Tuncks said:

Once, I was taking a hang-glider guy for a passenger flight in  glider. On tow, I let him have a go on the controls cos he seemed so good. In my recollection, I only took my eyes off the tug for a second to look around for other gliders etc. When I looked back, NO TUG! in panic, I looked around to find we ( the glider and tug ) were formating wing-tip to wing-tip. ( about 1500 ft ).

I sure learned a hard lesson from that... you never assume too much I learned.

But was not that glider collision the result of them entering cloud?

it was just a thought, its hard enough to see another plane with perfect vision.

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