For us shooters who wear prescription glasses there is an extra item on our checklist of things that need to work and align with our rifle or pistol. Most of us have been using special shooting glasses that can be adjusted to our position and hold of our firearm.
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If you are a rifle shooter you should also consider the glass holder that are now ISSF approved and available from various manufacturers.
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One example is the MEC Monocle which is easy to attach between your eye piece and body of your rear sight.
It lines up nicely with the line of sight and replaces a set of shooting glasses and is ISSF approved.
The AHG mono frame has a similar concept but caters to a wider variety of rear sights and shooting disciplines.
(Note: Not for ISSF)