no peephole.... solid
If you want to get even more technical just cut a small patch of scotch tape and hold your gun out like you are shooting. Close your right eye and open up your left eye and aim the gun like you would normally shoot. Have another person stick the small patch where it obscures your vision of the sight with the left eye. ( Just don't let him stand in front of the gun
It will exercises your right eye to get it used to doing the work.
or just get some lip balm and put on the lens...However, the downside is if you have a pair of prescription lens$$$ or $$$$ sunglasses the dust might stick in the lip balm and when you wipe of your glasses it might get scratched.