How can i convince my parents that video games aren't causing my epilepsy to get worse?

i have talked to my doctor alone without my parents in the room before and he has told me i am not photosensitive ( flashing images on video game screens and tvs do not affect me) and yet they still are persistent in stopping me from playing, it would not be a problem to me, its not like there my whole life but i have spend a large sum of money investing in these such as buying the disc and buying play time cards. I know its not the games that cause it i have tested it myself by playing for a week, having a seizure and then not playing for a week and still have them so can someone please give me a good argument to say to my parents?