EFFECT OF A CARBONIC ANHYDRASE INHIBITOR (DIAMOX) ON INTRA-OCULAR PRESSURE OF RABBITS AND CATS* BY

THE observation by Becker (1954) that the oral administration of a car-bonic anhydrase inhibitor, 2-acetylamino-1, 3, 4-Lhiadiazole-5-sulphonamide (Diamox, Lederle), causes a reduction of ocular tension in many glaucoma patients has been fully confirmed by other investigators (Grant and Trotter, 1954; Breinin and Gortz, 1954; Kleinert, 1954; Perkins, 1955). The efficacy of this drug is independent of the aetiology of the glaucomatous condition, a fact which suggests that it interferes with a basic mechanism concerned with the maintenance of intra-ocular pressure, and which has prompted investigations of its action on the intra-ocular pressure in normal animals. Grant and Trotter (1954) stated that intravenous injection of the sodium salt of Diamox reduced the intra-ocular pressure in normal rabbits, and Becker (1955) reported similar findings in rabbits and dogs. Becker estimated the intra-ocular pressure in conscious animals by tonometry, a procedure which has certain disadvantages, among these being the uncertainty of the absolute value of the intra-ocular pressures and the limitation of the number of readings which can be made in a given time; moreover, a simul-taneous record of, the blood pressure could not be obtained and this is essential since variations in blood pressure may have a significant effect on the intra-ocular pressure of experimental animals. These disadvantages can be overcome by obtaining continuous manometric records of the intra-ocular and blood pressure. Using such methods the following experiments were performed