The dot in any red dot sight can appear distorted, but in the case of Aimpoint sights anyway, it's not usually a mechanical problem in the sight. Ususally, it's just that the shooter's eye can not resolve the dot (worse with smaller dots) under the conditions present.
First, determine if the image distortion that you see is caused by the sight or not. The best way to do this is to look through the sight and make a note of the way the distorted image is oriented. For example, if the dot appears to have a "tail", is it at 2 o'clock or 6 o'clock? Next, roll the sight on its optical axis while looking at the dot. If the shape that you see rolls with the sight (like the spokes of a wheel) the sight has a mechanical problem and should be sent to Aimpoint (or the manufacturer in the case of other brands). If the image remains stationary in relation to the rolling sight, the problem is not in the sight at all.
Another experiment you can do is to look at the dot through a small aperture (like the rear sight aperture of an AR15). In many cases, you'll see the dot as it actually is, nice and round and clear. I'm not an optometrist, so I can't explain it, I just know that it works that way for me.
This apparent distortion is why Aimpoint opted to increase the size of the dots in our sights to 4 MOA from the old standard 3MOA dots. The majority of shooters that had problems seeing the 3 MOA dots clearly can see the 4 MOA dots better, and many have remarked that the dots actually appear smaller.
I hope this helps. If you have furter questions, please call our customer service department at 877-AIMPOINT.
Mike.