Every so often I see or hear a complaint about how someone just bought a new Red Dot optic(or similar reflex sight) and got a defective one with a screwed up reticle.
Now there are the occasional defective optic, but usually the answer is that the person has an astigmatism or other eye problem that they did not know about causing the dot to look like something other then a circle. I know a guy who bought an Aimpoint PRO and sent it back for being defective. He sent the replacement back also complaining how he was sent two defective optics in a row. It wasn’t the optics that had the problem.
So, how do we diagnose if the problem is the person or the optic? First option is to have someone else look through the optic. If that is not an option, simply rotate the optic when looking through it. Some people will see a J shape, or a figure eight(or similar infinity sign), multiple dots, etc. If these remain the same when the optic is rotated, it is the persons eye that is the problem. If this aberration rotates with the optic, the optic is at fault.
Most people will find that these issues go away when they wear their corrective lenses. Others learn to live with it, finding a point on the deformed reticle that they can use. For example the top of the J, or in between the circles of an figure 8. For some they can not deal with this so they do not use red dot type optics.