Every-one has a bit different facial set up. I have a pretty good sized skull with deep set eyes and find 19-20mm of eye relief necessary to get a relaxed full field of view. Less than that and it is not comfortable for me. Without glasses I have astigmatism and so will simply be magnifying distortion. Vortex Vipers in 8X42's work great for me. I cant find a 10x42 with enough eye relief though there are some 10x50's that can work. Also beware the eye relief measure from the company as some might measure differently. Best to try out the binos you want to try.
