Oxygen tension in the anterior chamber of the rabbit eye.

The oxygen tension in the aqueous humor in the anterior chamber of rabbit eyes was measured continuously with a polarographic electrode. The normal oxygen tension in the anterior chamber was 23 +/- 2 mm Hg (mean +/- SD, n = 4). A contact lens was then placed on the cornea for at least 10 min and the drop in oxygen tension recorded. A hard polymethylmethacrylate lens reduced the oxygen tension by 16 +/- 4 mm Hg, and a larger hydroxyethylmethacrylate soft lens (Soflens) decreased oxygen tension by 17 +/- 4 mm Hg (mean +/- SD, n = 4). Comparable statistically significant decreases were seen with the Permalens, Polycon II, and Silcon lenses. Only the elastofilcon A lens (Silsoft) did not decrease the oxygen tension in the anterior chamber significantly.