HI, the reason for this and gurning I believe is a nerve misfiring when flooded with serotin. Pupil dialation happens on all stims it's just some don't get it as bad.
Even Ritalin, enough and my eyes are blown - Ethylphenadate I casn snrot and I don't get unless I IV. MMCAT I am not so sure as my tolerence is different now but a few lines and they were huge.
Don't wear sunglasses in the house unless the sun is out. If I was out raven I'd assume they were on summit with glasses - unless you get them toy ones they sell. Normal glasses will help as they make your pupils hard to see.
Now this IS NOT a good idea but I used to do this. As coming home my mum is up, she'd notice - before leaving I'd bang some heroins they shrink. However, smoking it would be instant or another opiate. If you've no histoey of abuse/add for opiates then you may get off.
btw if you go outsdie or on a light/computer they will shrink (they are meant to) however if you're peakin or they still aint then look away as in time this may cause vision issues. I remember a myth LSD in the n you go blind, I thinkit was based on that.
I used to video/record me INjecting a speedball of Heroin/Cocaine and i've mixed it abit - the last time was Heroin and MMCAT. They immedity blow up and shrink midsizee. LOL insane.
it's not your eyes really that give it away it's all the other stuff (been up all night, bad mood, not eating or being open and talking)