Just got home from doctor. she said i have cataract. looked it up online and now more confused that ever. can you explain what it means to have it?

Lens clouding: A cataract is anything in the lens which prevents clear transmission of images. Most commonly this is an age related change. But they can occur from certain drugs and radiation as well as some infants born with them. Also trauma can cause them. Cataracts lower the vision and when the point has been reached that you cannot see well, they generally can be removed with restoration of good vision.

With vision problems: You should have your cataracts operated on cataracts when they affect your activitities of daily living. "you have problems doing things you like, or need to do", or there is medical reasons that the cataracts should be taken care of (causing glaucoma!). There is no set vision (i.e. 20/40 or 20/50) that indicates you should have surgery. You should have symptoms, or need to pass drivers exam.