If you have poor vision but want to dive, you can equip your mask with prescription lenses. If you think it is troublesome, you can wear contact lenses then with the mask. But personally, it is dangerous to wear contact lenses when you scuba dive. If you wear contact lenses, remember close your eyes if waters come in your eyes. But it will cause inconvenient. So, I suggest go to a eyeglasses shop and had your mask equipped with prescription lenses by an optician.
I am near sighted too. I still like you, having the habit of diving. I bought the diving glasses with prescription. It is very useful. I don' t have to worry about the vision. It is just like the common eyeglasses with prescription. It makes me see things under water. I just go to the amazon to buy one because the price there is more suitable. However if you have the astigmatism, the eyeglasses should be added with this function additionally. You need to tell the clients. The quality of the eyeglasses I bought is good. This summer I will still use it. Before you take the diving glasses, you need to put it in the water with clean agent to wash the lenses and then use your fingers to rub it on average. Then you should get rid of the water in the diving glasses. You could wear it then. This doing could help you not get the frosty symptom after you dive. You should remember this point which is very useful and important.