I have 20/25 vision with glasses or contacts. Without assistance, the reticle is blurry/pixelated. With assistance, it’s lots better. Still not a smooth circle but close. I like the setup, it works for me and will continue to use it.
They’ve always been kind of grainy to me, especially at the higher settings.
Astigmatism causes a starburst affect with red dots for a lot of people, but the EOTechs aren’t supposed to be as bad. I have 20/20 with astigmatism and I only notice the starburst on my Trijicons on extremely bright settings. Same with the Aimpoints, Vortexes, etc I’ve used.
What I've noticed is the Eotechs don't do well if you have any kind of astigmatism. If you do the AimPoints seem to do much better; at least in my case. Here is a decent video on detecting an astigmatism with your red dot sight.
I have a relative who is an eye surgeon (retired Navy eye surgeon, former President of the American Ophthalmological Society, and now head of the School of Ophthalmology at a major university medical school).
I posed this to him in an email in 2004:
I don't know if you have seen them, but many firearms, paint ball guns, and BB guns are now being equipped with something called "red dot" sights. They mount and look like a short, fat scope on a gun. The principle is simple, a little red LED shines towards the center of the front lens. The tiny little red dot reflection is seen by the shooter and covers the intended target.
The red dot is perfectly round. I know this because I took a photo of the image and enlarged it a bazillion times.
Now here is my question: When folks look through red dot sights, many of us see an irregularly (i.e., not circular) shaped red dot. Most everyone describes seeing a different shaped dot. And we see different shapes with our left and right eyes. And putting on eyeglasses changes the dot's apparent shape, too. A few actually see a perfectly circular dot.
I see something that looks more like a red "/" with my right eye. With my left eye, I see more of a "\" shaped red dot.
When I ask others to sketch what they see, folks sketch all kinds of different shapes.
Many people have bought red dot sights and returned them to the vendor with complaints that the sights are not displaying a round dot, thinking that the sight is defective.
I suspect the problem is astigmatism or something.
I think the problem is with our eyes because when we rotate the gun through 360 degrees, the irregularly shaped dot stays stationary---oriented the same way.
Do you have any thoughts on all this?
I am between patients; so will try to answer your question.
The red LED round image is the actual image of the dot generated within the sight.
Your perception depends on your own optical system--glasses, cornea and lens--the final image will be a result of low order (astigmatism and sphere) and higher order optical aberrations (coma, trefoil, etc).
The sight is like an optical aberrometer---the fewer (lower quantitatively) aberrations, the rounder it will appear.