It is with class assignments a bit of your learning and preparing for exams through creative ideas is done but if that friend is unable to do them means he is unable to do well even in his exams. 
You should be able to take out the feeling in your friend that the other students may tease him if he wears glasses. You should be able to convince him to wear a specs and that no one will tease him for wearing it.
studies are more important than the teasing. if you have education all people will be under your feet and then will never have the right to speak against you.