Hmm that's interesting, does he feel like the glasses are getting tilted at all while looking through the scope?Got some more info from my dad. He said the crosshairs in a scope lean to the left a little with glasses on (right eye astigmatism) and that contacts correct this. He says the contacts help his astigmatism better than the glasses, but everyday activities like watching tv, driving, or walking around the yard are good with both contacts and glasses.