Retina and cataract problem. Of oct?

My mother has some problem related to cataract and eye swelling in retina...so once the doctor asked us that he will do operation for eye for cataract but then he did not take any gurranty for eye sight. But when we met second doctor he did the first laser operation in eye to fill the holes in retina and then second doctor did the cataract operation successfully.and my mother has now good eye sight. But when we met with retina doctor he was saying that still there is some swelling in eye and he has to do OCT in eye but last time,when my mother did OCT from.first doctor,she faced the problem and she could not see properly and now she is afraid of doing OCT so should we go for it again??? I am also going for another doctor appointment but is it any side effects of OCT??? Please advise so that I can choose proper way for my mother...