"20/20" means "perfect vision". Eye doctors measure people's vision using two numbers. If the first number is low, your vision is good. If it's high, you aren't able to see well. I have 200/20 vision, so I really need to wear my glasses. But 20/20 is the lowest score and means that you're able to see perfectly. "20/20" is pronounced "twenty twenty".
by Ruth CR February 23, 2018