Reflections can be a problem with eyeglass wearers in certain light. Trust me, it is very difficult to remove large spots of glare in Photoshop off of the eyes and make it seem natural. It is much easier to avoid the problem in the first place. The first step to fixing this problem is noticing it WHILE you are shooting. Don’t wait until you are home in front of a computer to check out your shots, check on the back of the camera, zoom in and look at the face or faces to see if something needs to be adjusted. With glasses, it is often as simple as lowering your studio lights or light source, or changing the angle of the lenses. One simple trick is to have the subject raise the arms of their glasses slightly behind the ears. This points the face of the glasses down and often cuts out the reflection altogether. This is easy to do when the subject has a lot of hair (most women for example) but perhaps not an option on people with close cropped hair where the angle of the glasses will be more noticeable.
Both of these images were shot with natural light using a large patio door as the main light source. Note the large glare on Katie’s glasses in the left image. In the right image I got her to tilt her glasses up off her ears. I bet you wouldn’t have noticed if I hadn’t pointed it out. The glare is gone!