What distortion? The only problem i get with such high FOV is some missing textures on Artyom's arms and that's it.
If I can remember this correct 83 FOV is quite nice, not sure how you would change the field of view in Metro 2033, I know there's no such default option.
In most games I would change FOV if it felt cramped, esp since playing more 3rd person games. I don't like to do that in horror games though because more peripheral means less suspense.