A quick sight test answers one question: which lens makes the letters sharp. That is useful, and it is not the whole job.
An eye exam also asks how healthy the eye is. We measure pressure, look at the lens for early cataract, and examine the retina and the optic nerve, where diabetes and glaucoma first show.
We talk, too. How you use your eyes during the day changes which lens is right: a long drive, a day at a laptop and a day at a workbench need different things.
And we explain. If the numbers changed, you should know why, and what to watch for before next time.