Lucky you! If I want to see a front blade crystal clear, I have to reduce the aperture to such a small size that other optical effects occur. And that is a clue to a possible cause: are you using a very small peephole? As a rough guide, 1/16" is small enough, below that wierd things may happen, depending on lighting conditions. I see spiderwebs, you see double... with my Luger I see 3 foresight blades (a shadow blade left and right, looks like a mountain range!)... it depends a bit on your personal eye geometry... so open up the aperture, and if the effect disappears, note the minimum size that does not produce the aberration. This is light-dependent - in dimmer light the hole must be enlarged.
Second test: When you get the double-hole effect, try moving your eye up and down relative to the peephole. If the doubling can be made to disappear in this manner, then you first need a real eye-doctor to make sure that the aberration is not a symptom of something serious, as already recommended, and (assuming an all-clear from the doc) an optometrist who understands what you need as a shooter. And that means spending some time getting it right. You will have problems if you simply march in to the opticians with a rifle - what I did was to take along a meter rule with the backsight aperture and foresight taped on at the correct distance.
You are likely to need shooting glasses with a lens specifically adjusted to suit the distances of the foresight/backsight from the eye. And accordingly a second lens if you also shoot handguns, because of the different focussing distance. But in the end, the lenses are cheaper than wasting a lot of ammo and range time.