I have SPD along with autism, and I don't have any problem seeing 3d movies. Occasionally, I get a little dizzy while adjusting to the glasses, and because I have a habit of pushing them up and down to see it change from 3d to blurry over and over again, but other than that, I don't have issues. I don't find 3d movies louder than 2d ones. Some theatres are louder than others, but it has nothing to do, IMO, with 3d or 2d. I take earplugs with me, and use them sometimes. I find 3d often looks realistic, and since I am used to seeing everything in 3d in my everyday life, it doesn't cause me problems to see it in the theatre.;
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Diagnosed with classic Autism
AQ score= 48
PDD assessment score= 170 (severe PDD)
EQ=8 SQ=93 (Extreme Systemizer)
Alexithymia Quiz=164/185 (high)