It's you and not the red dot! Specifically your eyes and astigmatism

Red dot not looking right? 

Well...We hate to break it to you, but it could be that you have an astigmatism. 
a·stig·ma·tism is defined as:

"a defect in the eye or in a lens caused by a deviation from spherical curvature, which results in distorted images, as light rays are prevented from meeting at a common focus."

In layman's terms, anyone with an astigmatism that uses a red dot will get a distorted dot.  Ranging anywhere from a blurry dot, crescent, star burst, multiple dots, or anything that does not look like a perfect dot.  

So how do you get around astigmatism while looking through your red dot? 

We're not optometrists, but here are a few common ways to treat your astigmatism.   You can get corrective lenses "glasses", contact lenses, or the most expensive solution would be getting a corrective procedure like Lasik.  Please note that these solutions are not always guaranteed to work, as for myself, I got the Lasik procedure done and still struggle with astigmatism and red dots.  

How do you know if it's you or the red dot?

This is pretty simple and easy.  One method of testing to see if the red dot is defective or if your eye is playing tricks on you is to physically check the red dot.  This is a simple test that will definitively determine whether or not your optic has a mechanical defect or if it is your eye.  The first thing you will need to do is remove the optic from you firearm, please observe all firearms safety rules while handling firearms.  With the illumination engaged, hold the optic in front of your shooting eye like you are looking through the optic.  While holding the optic in front of your eye begin to rotate the optic around the dot, using the red dot as your axis.  While doing this you should observe one of two things, either the malformed dot will remain stationary or the malformed dot will rotate with the optic. If the dot remains stationary and does not rotate with the optic then, regretfully, the problem most likely lies with your eyesight.  If the malformed dot literally rotates with the optic as you rotate the optic then the issue is most likely mechanical and your optic is defective.  Another method of determination is where you take a picture of the dot through the optic with a camera.  Your camera lens will not have an astigmatism and it will show you if the dot is perfect or not.  A common mistake that people make can be having a friend take a look at the red dot.  Your friend may or may not know if they have an astigmatism and when they look through the red dot they may have the same outcome as you.  It's just easier to take a picture.

Red dot alternatives for astigmatism.

For me, I still run red dots and live with my astigmatism as I don't need precise shots at close quarters.  At distance, this is probably not a good option.  The best solution would be to use a 1x fixed prism like the upcoming Atibal SAP, which uses a laser etched reticle versus an illuminated dot.  The great thing about 1x prisms is that they will still maintain a small footprint like a red dot, but with a laser etched reticle that will not have the distortion/starburst effect.  The other option is to go with a low powered variable optic (LPVO).  Yes, this option is much larger than a red dot but will give you much more versatility.  Same as a prism, it also uses a laser etched reticle.  With the LPVO you can use it at 1x magnification, much like a red dot, for fast target acquisition in close quarters all while having the capabilities of increased magnification for longer distance and more precise shots. 

Here is a list of some Atibal LPVO's and prisms for your AR and astigmatism: 

Magnification: 1-4x
Objective Lens Diameter: 24mm
Eye Relief: 4 inches
Field of View: 22–83 feet / 100 meters
Tube Size: 30 mm
Magnification: 1-6x
Objective Lens Diameter: 24mm
Eye Relief: 4 inches
Field of View: 116.5-19.3 ft
Tube Size: 30 mm
Magnification: 1-8x
Objective Lens Diameter: 24mm
Eye Relief: 4 inches
Field of View: 105-12.45 ft
Tube Size: 30mm
Magnification: 1-10x
Objective Lens Diameter: 30mm
Eye Relief: 3.6 - 5.5 inches
Field of View: 101ft @ 1x - 10.1ft @ 10x
Tube Size: 35 mm

Magnification: 1x
Objective Lens Diameter: 11mm
Eye Relief: 4"