If you wear glasses or contacts, you have a few options for diving.
Note that most of the interesting things diving are closer up. So if you're middle-aged (like I am), you may want to use an indoor prescription for your scuba mask - that is, one that focuses a little closer and doesn't reach out to infinity.
My favorite solution is a SeaVision full prescription mask (see below), since I have a lot of astigmatism in one eye and I need bifocals to see my camera LCD screen.
Wear contacts and hope
If you're good about keeping your eyes closed when you have water in your mask, you may be able to get away with a normal mask. If you open your eyes in the water, though, one of your contacts may wash out. So if you need them to function on the boat (or drive home), make sure you keep a spare pair of contacts or a pair of glasses in your save-a-dive kit.
Weighted contacts for astigmatism do not work very well underwater. They rely on gravity to pull the contact into the right orientation. But if you're diving looking down or sideways, they can rotate and things will be out of focus.
Premade prescription inserts in a normal mask
The lenses in some masks can be swapped out for ones with a fixed magnification. This works ok if you have a simple prescription without astigmatism. Each eye can have a different magnification.
Glue-in bifocal inserts
If you wear bifocals or reading glasses above water, you may need bifocals below water too. You can get bifocal inserts that glue inside of a normal mask. The glue softens in hot water, so you can remove or readjust them if you don't like how you positioned them the first time.
Full prescription mask
SeaVision USA makes full prescription masks in a few different shapes and colors. These can correct for astigmatism, and you can get bifocal spots built into them. The lenses are made from a strong plastic that in my experience will take a lot of abuse, so they're lightweight and they block UV light.
I've used their masks for years and love them. Good customer service, too. They made and shipped a replacement mask to me on a tight schedule, when I lost my prescription mask on the dive before I left for a big dive trip.
(They didn't give me anything to say this. I'm just really happy with them.)