THE OCULAR BLOOD-FLOW TONOGRAPH - A NEW INSTRUMENT FOR THE MEASUREMENT OF INTRAOCULAR-PRESSURE IN RABBITS

The Ocular Blood Flow Tonograph (OBFT) and Digilab Pneumatonograph (PT G) were calibrated for use on New Zealand White rabbits using a pressu re manometer and performing tonometry at varying known pressures. The calibration experiments showed that a good correlation exists between OBFT measurements and manometric readings of IOP. Moreover, no differe nce between open and closed stopcock measurements were observed, Corre ctive equations for conversion of OBFT readings to mm Hg are documente d. The OBFT was compared with the PTG and the results showed there was no significant difference between the IOP measured by either instrume nt in a group of rabbits displaying a range of different IOPs. Regress ion analysis of the data gave a slope of 0.88 and a correlation co-eff icient of 0.78. The OBFT proved easier to use than the PTG under restr icted lighting conditions. The OBFT was also used to measure the circa dian variation in IOP and to measure the IOP after the topical applica tion of prostaglandin E(2) and various serotonergic agonists. The comb ined data demonstrated that the OBFT is an accurate and reliable tonom eter for the measurement of IOP in rabbits. (C) 1996 Academic Press Li mited