RT Journal Article
SR Electronic
T1 Optic nerve oxygen tension: effects of intraocular pressure and dorzolamide
JF British Journal of Ophthalmology
JO Br J Ophthalmol
FD BMJ Publishing Group Ltd.
SP 1045
OP 1049
DO 10.1136/bjo.84.9.1045
VO 84
IS 9
A1 M la Cour
A1 J F Kiilgaard
A1 T Eysteinsson
A1 A K Wiencke
A1 K Bang
A1 J Dollerup
A1 P K Jensen
A1 E Stefánsson
YR 2000
UL http://bjo.bmj.com/content/84/9/1045.abstract
AB AIM To investigate the influence of acute changes in intraocular pressure on the oxygen tension in the vicinity of the optic nerve head under control conditions and after intravenous administration of 500 mg of the carbonic anhydrase inhibitor dorzolamide. METHODS Domestic pigs were used as experimental animals. Oxygen tension was measured by means of a polarographic electrode in the vitreous 0.5 mm anterior to the optic disc. This entity is called the optic nerve oxygen tension. Intraocular pressure was controlled by a hypodermic needle inserted into the anterior chamber and connected to a saline reservoir. RESULTS When the intraocular pressure was clamped at 20 cm H2O optic nerve oxygen tension was 20 (5) mm Hg (n=8). Intravenous administration of dorzolamide caused an increase in optic nerve oxygen tension of 43 (8)% (n=6). Both before and after administration of dorzolamide optic nerve oxygen tension was unaffected by changes in intraocular pressure, as long as this pressure remained below 60 cm H2O. At intraocular pressures of 60 cm H2O and below, dorzolamide significantly increased optic nerve oxygen tension. CONCLUSION Intravenous administration of 500 mg dorzolamide increases the oxygen tension at the optic nerve head during acute increases in intraocular pressure.