Can extra d improve my vision, been taking it cause my bones were brittle, and when i needed new glasses they said my eyes got better, i take 2000 iu'?

Not related at all: It is terrific that your eyes got better but it is not because of the vitamin d.

No: Vitamin d does not improve your vision, even if you had vitamin d deficiency. There are some recent claims that vitamin d deficiency might play a role in age related macular degeneration in mice. Even in that case, restoring vitamin d would not fix the damage. People your age often experience visual fluctuations from presbyopic eye strain and developing cataracts. Early cataract can sometimes offs.