Ive had this happen.

Particularly when kneeling and working on something for a period of time. When you stand back up there is a rush of blood to the legs below the knees and this creates a temporary pressure drop to the brain like bird says.

Seems to coincide with smoking mj with me. Lasts about 20 seconds but can sometimes make vision look like static on a tv set and I have to grab something momentary. Not always, but know what your talking about.
Fairly common with mj smokers, called "head rush".

I smoked with a guy one time and he was kneeling down working on his truck, stood straight up. Fell backwards stiff as a board and bonked his head good on the concrete. After watching that always make sure to grab on to something.
Ganjasaurusrex Reviewed by Ganjasaurusrex on . Standing up fast-blindness hallucinations Since ive been smoking so much good chron, and alot of it, sometime if i stand up fast (even when im not high) i will go blind, and start having random hallucinations for a few seconds. Things like outlines of faces appearing in a light tracer format. Also it feel really overwhelming when it happends, i loose balance, and see shit, and cant see properly... Just wondering if anyone else has had this.. might be because i hold my breath as i stand up (a habit of mine since i have been Rating: 5