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View Full Version : Astigmatism? Distortion? Field Curvature?



chuckbuster
05-27-2019, 07:23 AM
Here's a new one for me (and it's something else to talk about besides how Selfie the Clown intends to put it to us dry).

I've had poor eyesight since I entered my teenage years. And as I've gotten older, I first found open sights (a la Winchester 94 etc) more and more difficult to use, then peeps as the range increased as well. So now, I'm at a point where magnified optics of some type are pretty much a given (although, I find the XS sights on my .45-70 still usable at the short ranges at which deer are normally shot in the Ontario bush). Anyhow, now, I've experienced something new. I put a Bushnell Elite 3500 4-12X with a DOA reticle on a rifle and much to my surprise, after looking through the scope for about 15s, the field of view and the reticle begin to distort. To get an idea of what I see happening, take a look at the Salvador dali painting of "melted" clocks. At the end of this moving distortion, I end up with a field of view that is oblong from upper left quadrant through to the lower right and the crosshairs tilted that way as well. At first I thought the scope must be defective, but now I'm not so sure.

I asked a friend and a few random guys at the range to look through the scope to see if they saw what I saw and not a one saw it. I looked through my friend's 3-9X 3500 and did not get the effect. I also did not get the effect when looking through another of my own scopes (although, I'm going to look through a few of them tonight, side by side, to check and make sure).

So, I'm not sure what to make of this. I've been told over the years that I have some astigmatism and I'm wondering if astigmatism can cause such a visual anomaly and if I'm seeing it for the first time. Anybody out there have any insights or perhaps a similar experience, or astigmatism...?

Stew
05-27-2019, 09:26 AM
I have astigmatism but haven't noticed ill effects when using scopes

JustBen
05-27-2019, 10:04 AM
I also have astigmatism, but I have not experienced what you describe. Does the scope have adjustable parallax? That’s my first thought...

chuckbuster
05-27-2019, 11:01 AM
The scope doesn't have a separate parallax adjustment. As I said, this is the first time I've ever experienced this; and of course it's a real head scratcher since everybody else who looks at it doesn't see it.

JustBen
05-27-2019, 11:07 AM
The oblong field of view makes me think bent tube.... but others should see that.

chuckbuster
05-27-2019, 11:17 AM
The oblong field of view makes me think bent tube.... but others should see that.

True...I just don't get it. A real head scratcher.

Stew
05-27-2019, 02:18 PM
next stop ophthalmologist

chuckbuster
05-27-2019, 07:55 PM
next stop ophthalmologist

Yeah...The Boss made a similar statement when she overheard me discussing it...

On a side note, I noticed it again tonight and possibly on a couple of other scopes, but whatever it is it is most pronounced on the 3500. However, I would have to say that it is probably something with my eyes/vision as opposed to the scope itself.

blacksmithden
05-27-2019, 08:48 PM
Welcome to getting older. It's like being forcibly entered into the daily "what's my body going to do to me today" lottery.

Justice
05-28-2019, 11:48 AM
Open sights a la Winchester 94 are crappy sights to start with for everybody. You're trying to focus on 3 things at once and that just isn't possible. Peeps are better, but you're still focusing on more than one thing.
"...field of view and the reticle begin to distort..." Bushnell's QC is reported as having gone down hill.
"...looked through my friend's 3-9X 3500 and did not get..." That pretty much proves it's the scope.
You should talk to your ophthalmologist anyway and tell him what happened. Got new specs this past January and was diagnosed with glaucoma in one eye. Wouldn't have known at all if I hadn't seen the ophthalmologist.

chuckbuster
05-29-2019, 07:20 AM
^I'm not so sure it's the scope anymore simply because nobody else who has looked through it sees any distortion at all.

Stew
05-29-2019, 01:38 PM
^I'm not so sure it's the scope anymore simply because nobody else who has looked through it sees any distortion at all.

go to ophthalmologist, nearly all eye problems can be solved

Bittereinder
05-29-2019, 03:17 PM
Perhaps there is something slightly "off" in the scope, maybe in or out of spec, that isn't noticeable by most people but for some reason it doesn't look right given your particular astigmatism?

JustBen
05-29-2019, 06:00 PM
Here is a thought - does what you see change on whether or not you have prescription eyewear on? Maybe you’re not quite getting the correct correction?

chuckbuster
05-29-2019, 07:20 PM
go to ophthalmologist, nearly all eye problems can be solved


Perhaps there is something slightly "off" in the scope, maybe in or out of spec, that isn't noticeable by most people but for some reason it doesn't look right given your particular astigmatism?

I'm thinking a visit to the optometrist is the first order of business to rule out any refractory errors with my eye. He would also be able to identify any pathology that would require a follow up visit with an ophthalmologist.


Here is a thought - does what you see change on whether or not you have prescription eyewear on? Maybe you’re not quite getting the correct correction?

I haven't thought of that...but then, I'm not sure if there is enough focus adjustment on the scope to accommodate for my terrible vision!

On a side note, while looking through it again tonight, I observed that the effect has diminished from my initial report. Playing with focus and position has been helpful. Still, it doesn't explain what happened originally.

Stew
05-30-2019, 11:24 AM
go directly to ophthalmologist, skip optometrist until you need glasses, that's what they're for