▁a ▁few ▁minutes . ▁ ▁This ▁is ▁significant ▁for ▁example ▁if ▁the ▁patient ▁requires ▁an a est hes ia ▁for ▁a ▁tra uma ▁and ▁has ▁sust ained ▁an ▁eye ▁( g lo be ) ▁per for ation . ▁ ▁The ▁mechanism ▁is ▁not ▁clear ▁but ▁it ▁is ▁thought ▁to ▁involve ▁contra ction ▁of ▁t onic ▁my of ibr ils ▁and ▁trans ient ▁d ilation ▁of ▁ch or oid al ▁blood ▁vessels . ▁ ▁K et am ine ▁also ▁increases ▁I OP . ▁ ▁Sign ific ance ▁O cular ▁hy pert ension ▁is ▁the ▁most ▁important ▁risk ▁factor ▁for ▁gla u com a . ▁ ▁In tra oc ular ▁pressure ▁has ▁been ▁measured ▁as ▁a ▁secondary ▁outcome ▁in ▁a ▁system atic ▁review ▁comparing ▁the ▁effect ▁of ▁ne uro prote ct ive ▁agents ▁in ▁slow ing ▁the ▁pro gression ▁of ▁open ▁angle ▁gla u com a . ▁ ▁D iffer ences ▁in ▁pressure ▁between ▁the ▁two ▁eyes ▁are ▁often ▁clin ically ▁significant , ▁and ▁potentially ▁associated ▁with ▁certain ▁types ▁of ▁gla u com a , ▁as ▁well ▁as ▁ ▁ir itis ▁or ▁ret inal ▁det achment . ▁ ▁In tra oc ular ▁pressure ▁may ▁become ▁elev ated ▁due ▁to ▁an atom ical ▁problems , ▁infl amm ation ▁of ▁the ▁eye , ▁gen etic ▁factors , ▁or ▁as ▁a ▁side - effect ▁from ▁medic ation . ▁In tra oc ular ▁pressure ▁laws ▁follow ▁fund ament ally ▁from ▁physics . ▁Any ▁kinds ▁of ▁int ra oc ular ▁surg ery ▁should ▁be ▁done ▁by ▁considering ▁the ▁int ra