I recently got a 1-5x and trying out LPVO again (sweet deal on a Burris xtrii 1-5). I have a very mild astigmatism that only shows up when my eyes are tired and makes my aimpoints / rmrs look a little more of an oval than crisp dot. No big deal.

Anyways - last night, trying to set the diopter on this LPVO was a huge pain.

- If I set it to look crisp at 1x without illumination and both eyes opened, the reticle and edges looked great.
- I turn on illumination and use both eyes, the reticle loses focus when I open my left eye and try to use like aimpoint.
- set diopter so the reticle with illumination looks good, I get a ton of edge distortion (large area of image perimeter is out of focus but center looks good)

It seems I couldn't find a setting where all scenarios looked good (1x, 5x, illumination, no illumination, one eye, both eyes).

I will try again today with rested eyes (long week with lots of time at computer) ... but anyone got tips on this?

ETA:  I briefly had a P4xi and recall similar issues getting diopter set in a way I was happy with.

- is this a common issue?
- is this an issue with my eyes/brain or are some scopes more susceptible to this?

My method

Big blank sheet of white paper
take a quick look at reticle....make diopter adjustment...don't spend more then 10-15 seconds...then look away.

I repeat that until I can mount the gun...look at the reticle and its sharp and in focus.

Sort of how you're ophthalmologist switches lens out and asks which one is better.

One eye or both eyes?
1x or 5x?
illum or no illum?

Set diopter at max mag

I go both eyes open on 1x with non illumination.

I believe your scope is second focal plane, so any magnification should be ok as the reticle is always the same size. If it was first focal plane, you should set it while at max magnification.

I don't use illumination when adjusting the diopter, but if you want to, turn down the illumination. The highest setting will only exacerbate your astigmatism as you've experienced.

Look at your target and then bring the scope into your line of sight quickly a couple times. The reticle should be crisp immediately, not after a couple seconds of your eye adjusting to it.