a BUNCH of things can cause bad night vision. yes, vitamin deficiency is certainly one of them...but that IMO is not the most common cause. also there are: inherited traits, systemic diseases, retinal problems (like you mentioned) and many more things.
one of the most common causes of night vision problems is HIGH ORDER ABERRATIONS like spherical aberration, trefoil, coma and others. to make a long story short, there are many more things that make the human eye blurry than just nearsightedness, farsightedness & astigmatism (the 3 of those being called "low order aberrations"). most of these other things (or "high order aberrations") are not correctable with today's technology. MOST people who have good vision during the day time and poor vision at night either have uncorrected low order aberrations (like wearing a glasses or contact rx that is not just right) or have a disproportionate amount of high order aberrations. a big culprit of this is people who have larger-than-average pupil size...they get a lot of spherical aberration (one of the high order aberrations).
so i guess what i'm telling you is that while vit-A deficiency certainly causes poor night vision, it is a rare cause. most people with poor night vision have it b/c of something else, and its usually an optical problem, not a disease or vit deficiency.
oh, i forgot to add that retinal surgeries definitely cause night vision problems and high order aberrations.
Thanks for the reply. Why do the retinal surgeries definitely cause night vision problem? Not all retinal detached folks have this problem, correct? Also, based on your previous explaination, the night vision problem caused by retinal surgeries is permanent?
Thanks again.