Any physical lengthening or shortening of the eyeball will invariably impede vision. When you change the focal length you change where the image is focused, either behind or in front of the retina.
This guy has never reproduced and will never reproduce. He has a great life but not every owner would be able to take care of such an animal, as he must be hand-fed (he always jumps short of the cricket if given the chance to chase it down). Feeding this guy by hand is definitely an art form and it is not something I could teach, it's based on 7 years of reading each other's movements and behaviour (to prevent me from getting bitten and to ensure he gets a good meal).
I actually really enjoy the way he looks, and since I know that he is no worse off because of it, I think it's okay to giggle at his googly eyes every so often, he has a sense of humour

Ryan