In what are the ways can I do to protect my vision if I have cataract?

Several. Quality sunglasses that will block uv-a and uv-b rays, stop smoking (if you smoke) and ocuvite (or equivalent) vitamins. Be wary of cheap sunglasses as they do not block the uv rays as effectively, yet the tint will dilate your pupils allowing more uv rays to enter your eyes.
S/p Cataract surgery. post Cataract Surgery protect eyes from UV exposure with sunglasses; most lens implants protect eye but check with eyeMD to be sure. Always eat green leafy veggies if ok with PCP to keep retina healthy.