Hyperbaric and transcorneal delivery of oxygen to the rabbit and monkey anterior segment
L. M. Jampol, C. Orlin, S. B. Cohen, C. Zanetti, E. Lehman and M. F. Goldberg
Department of Ophthalmology, Northwestern University, Chicago, IL.
When delivered to the corneal surface of rabbits for 30 minutes, 100%
oxygen can significantly increase the mean (+/- SD) partial pressure of
oxygen (PO2) in the aqueous humor (from 63.5 +/- 12.3 mm Hg [n = 12] to
139.5 +/- 32.4 mm Hg [n = 8]). Similar elevations were seen in monkeys.
Under hyperbaric conditions (2 atm) for 30 minutes the aqueous PO2 in
rabbits breathing room air can be increased to 295.2 +/- 132.4 mm Hg (n =
7) by exposing the rabbit cornea to 100% oxygen for 30 minutes. The high
PO2 under these hyperbaric conditions is mediated by both vascular and
transcorneal delivery of oxygen. The increase of PO2 in the rabbit aqueous
can prevent or reverse sickling of intracameral human erythrocytes
containing sickle hemoglobin. The exposure of rabbit eyes to 100% oxygen at
the corneal surface is followed by autoregulation (constriction) of the
iris vasculature. Transcorneal or vascular delivery of oxygen to the eye
under normobaric or hyperbaric conditions may possibly benefit patients
with hypoxic diseases of the anterior segment such as anterior segment
necrosis, rubeosis iridis, or sickle cell hyphema.
