Help with sighting issue

Guys it looks like I have an eye problem.  I've been shooting a vernier tang sight on my Pedersoli Sharps rifle for a while and I noticed what I thought was a burr or fuzz in the aperture.  I thought the problem was because the sight was not perpendicular to the bore so I did some alterations to the sight and the burr disappeared.  
However, I received my new vernier sight yesterday and looked through it and saw another burr!  From what I could find out the aperture has a .050" hole and I could slip a needle into the hole but could not remove the burr. I contacted Pedersoli yesterday via email and asked for a new aperture or one with a larger hole.  
Then just by chance I looked through the aperture with my other eye and presto, the burr was gone!  I want to use this sight and not return it but those of you with more experience can you tell me "will a larger hole in the aperture help removing this optical illusion?"
If so, I can bore it out a little bit at a time until it disappears.  I have a full set of wire size bits and a drill press. I also have a set of needle files. Instead of drilling out I can use the round one and try reaming out the hole until I get a clear picture it you think that will help.

OK I think I solved my own question.  When looking through the .050: hole I get what looks like a burr running from about the 10 O'clock position about 3/4 across the hole toward about 4 O'clock position.
I duplicated the same thing by poking a similar size hole with a pin through a dark paper and looking through it.  Then I poked a .062" hole in the paper and the burr image has almost disappeared. Still visible but barely. Not enough I don't think to affect me lining up the globe sight.
My last eye appt my optomatrist said I was starting to get cataracts but they shouldn't be a problem right now. I guess he's not a shooter!