Help asap please 10 easy points?

Well I have astigmatism I'n both eyes and for some reason only my left eye sees good with the glasses on but my right eye still sees double even with the best lens he tried but he says he those not see anything wrong with my eye but is referring me to a specialist to see why my right eye is still seeing double anyways he said it's not neurological but I'm scared it might be ALS or something worse I'm a healthy 18 year old male and my legs twitch occasionally that's a sign of ALS so could it be ALS or keratoconus the doctor checked my eyes real good he took like 40 minutes looking in them with a whole bunch of stuff also why when i look at black background's with white letters with my glasses on do i see double