Applanation Tonometry in the Conscious Cynomolgus Monkey (Macaca Fascicularis)

Abstract

Four monkeys (Macaca fascicularis) were trained to tolerate applanation tonometry while fully conscious. The tonometer used was the Draeger tonometer with an applanation area of 3.06 diameter, but with a reduced application surface (4 mm instead of 6.8 mm diameter). The reduction did not change the calibration and is applicable in this monkey species without any correction factor. The mean intraocular pressure determined was 19.12 mmHg.

Effect of general anesthetics on IOP in elevated IOP mouse model

“…Because almost all agents for general anesthesia affect the IOP in both humans and animals (Almeida et al, 2004; Artru, 1995; Ausinsch et al, 1975; 1976; 1977; Adams and Barnett, 1966; Badrinath et al, 1986; Bito et al, 1979; Burke and Potter, 1986; Bunch et al, 2008; Camras et al, 2010; Erickson–Lamy et al, 1984; Gelatt et al, 1977; 1982; Hahneberger, 1976; Hahnenberger 1976a; 1976b; Hayreh et al, 1991; Hofmeister et al, 2006; 2008; Jia et al, 2000; Johnson et al, 2008; Komaromy et al, 1998; Krupin et al, 1980; Mirakhur et al, 1990; Mowafi et al, 2003; Murphy, 1985; Nagdeve et al, 2006; Sator-Katzenschlager et al, 2002; Schäfer et al, 2002; Schnell et al, 1996) and the repetitive use of anesthetics might cause either neuronal degeneration (Istaphanous and Loepke, 2009; Mellon et al, 2007) or neuroprotection (Hudetz and Pagel, 2010; Koerner and Brambrink, 2006; Mortier et al, 2000) in glaucomatous retina, measuring IOP from conscious animals would avoid the un-wanted effects of anesthetics on the IOP measurement and potential anesthesia-induced confounding of experimental results. Towards this end, measuring conscious IOP in rats after behavioral training seems to provide a reliable measurement of IOP.…”

“…Numerous reports have shown that various anesthetics could alter IOP in humans (Ausinsch et al, 1975; 1976; 1977; Adams and Barnett, 1966; Badrinath et al, 1986; Mirakhur et al, 1990; Mowafi et al, 2003; Murphy, 1985; Nagdeve et al, 2006; Sator-Katzenschlager et al, 2002; Schäfer et al, 2002), monkeys (Bito et al, 1979; Burke and Potter, 1986; Bunch et al, 2008; Erickson–Lamy et al, 1984; Hahneberger, 1976; Hahnenberger 1976a; Hayreh et al, 1991; Komaromy et al, 1998; Krupin et al, 1980), dogs (Almeida et al, 2004; Artru, 1995; Gelatt et al, 1977; 1982; Hofmeister et al, 2006; 2008), cats (Burke and Potter, 1986; Hahnenberger, 1976b), rabbits (Burke and Potter, 1986; Schnell et al, 1996), rats (Jia et al, 2000), and mice (Camras et al, 2010; Jia et al, 2000; Johnson et al, 2008). Most of the anesthetics have been reported to decrease IOP in human and other animals.…”

Influence of Cataleptoid Anaesthetic Agents on the Intraocular Pressure in Monkeys (Macaca Fascicularis)

“…Tonometer. The Draeger tonometer (Draeger 1966) used was a slightly modified version previously described (Hahnenberger 1976b).…”

“…This dose induced only a calming effect with obvious visual, auditory and pain perception and no anaesthesia. The animals did not adapt a supine position, but remained sitting in their cages without evident loss of muscular tone and thus in a perfect condition for tonoinetry in the way described previously (Hahnenberger 1976b).…”

“…It was therefore the aim of the present study to evaluate possible IOP effects of three cataleptoid drugs, Phencyclidine, Ketainine and CI-744 in conscious monkeys. A method of conditioning monkeys to allow an applanation tonometry while conscious was described in another paper (Hahnenberger 1976b). Such animals were used here and the IOP measurements in the undrugged state were regarded as the normal values.…”