Is it hard to buy contact lens in Japan?

I'm going to study in Japan but I'm near-sighted. I wonder is it hard to buy contact lens at there. Do I have to make an appointment with doctor every time? Should I bring contact lens from my country? If my glasses is broken what should I do? I'm a little bit nervous because I have no idea about this thing. Any advice are welcome! Thank you very much.

PS. I'm appreciate if you can answer me about mobile phone also. Is it good to bring iphone from my country or buying new one in Japan is better?

Bring your own contacts, and glasses. Have your current doctor write out your prescription. You shouldn't have any problems.
You can rent a cell phone while you are there.

You don't need to go to a doctor every time you buy a lens. Just go to a doctor first, get prescription, then you can buy a contact lens or glass as many times as you like.

Hi
contact lens are easily available

Your foreign prescription will be useless in Japan. You need to have an eye test and obtain a Japanese prescription, but after that you will have no problem getting contact lenses or glasses.
You need to know hiragana to take the eye test.