Intraocular oxygen tension measured with a fiber-optic sensor in normal and diabetic dogs.

A new fiber-optic O2 sensor was used to measure the O2 tension in the living dog eye, and the results were compared with simultaneous O2 tension measurements with polarographic electrodes. The fiber-optic sensor and the polarographic electrodes gave similar readings of anterior chamber O2 tension and gave an identical response to elevation of inspired O2 levels. In the preretinal vitreous, the fiber-optic probe measured the O2 tension 26 +/- 5 mmHg (means +/- SD, n = 5), whereas the polarographic electrode showed 23 +/- 7 mmHg (means +/- SD, n = 5) in the contralateral eyes. Breathing 100% O2 raised the preretinal O2 tension similarly with both systems. Preretinal O2 tension was measured with the fiber-optic sensor in seven alloxan diabetic dogs and was 26 +/- 7 mmHg, which is not significantly different from normal dogs. The fiber-optic sensor has some advantages over the polarographic electrodes. The fiber-optic sensor does not consume O2 and is not dependent on the diffusion characteristics of the medium or changes due to stirring or fluid currents.