Forums: Community: Skydivers with Disabilities:
Varying depth perception


BlindBrick  (C 35382)

Nov 10, 2005, 3:54 PM
Post #1 of 4 (1011 views)
Varying depth perception Can't Post

Three years ago i had a corneal graft in my left eye, followed by the right eye 9 months later. I was back jumping within a few months of each surgery. Didn't have any major problems flying the low performance F-1-11 mains.

About a year aqgo I upgraded to a HP elliptical canopy and didn't have too much toruble. Seven months ago, my right cornea entered rejection. At the time, it wasn't majorly effecting my jumping. I've been on anti-rejection drugs since then and am progressing well.

The problem is that in the last month I've noticed that my flare is a split second off. I'm pretyy anal about analyizing things and nothing has changed about my canopy or technique. Yet i'm consistently flaring late. I thought it might have soemthing to do with my rejection so I went back to the Ophtamologist. My vision is now actually better than pre-rejection levels and my depth perception is way above average.

This is very confusing to me, because I'd think that if my vision was improving the tendancy would be to be flarign earlier rather than later sicne the sight picture I am used to would be occuring earlier.

Is my thinking right, or is there something related to vision that I am overlooking?


Premier faulknerwn  (D 17441)
Nov 11, 2005, 7:59 AM
Post #2 of 4 (984 views)
Re: [BlindBrick] Varying depth perception [In reply to] Can't Post

I can't say on your specific situation, but a few years ago I had LASIK. I had horrible vision before but it was correctable with contacts. After the LASIK, I consistantly was flaring about 5 feet higher than I ever had been before. It was very strange and hard to retrain from old habits!


Odin  (A 10613)

Nov 13, 2005, 11:33 AM
Post #3 of 4 (957 views)
Re: [faulknerwn] Varying depth perception [In reply to] Can't Post

Not sure if it helps, but as a one-eyed flyer, the tendency to flare early is really common with altered depth perception. I got really good at rolling in my landings until I figured out the correct picture. If your vision is now better than before, it sounds like you need to change your picture of when to flare. You were likely focusing in with a squint to see the big picture; now, you're seeing it for real and it is too late.

peregrinerose  (D 28983)

Nov 15, 2005, 8:27 AM
Post #4 of 4 (942 views)
Re: [BlindBrick] Varying depth perception [In reply to] Can't Post

Visual perception is a lot more than just depth perception. When you have any kind of corneal or lens surgery (including cataract surgery, refractive surgery, corneal grafts, even going from glasses to contact lenses) the image size on the retina is different. This takes a bit of time for your brain to figure out how to interpret, but is nothing you would notice consciously as it is very very minisculely (is this a word?) different.

The other issue is aberration. No eye is perfect, there are all kinds of aberrations in the lens, the cornea, etc. Your brain gets used to that too, so when those aberrations change slightly do to any of the above procedures, it's one more thing that your visual system needs to adapt to.

I don't know if you are wearing RGP contact lenses or not, but they can often improve your visual acuity and decrease aberrations beyond what glasses do in irregular corneas. That also may help a bit.

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