Comparison between the tonographic effects of pilocarpine and echothiophate iodide in glaucoma simplex.

Abstract

ACCORDING to Becker, Pyle, and Drews (1959) the instillation of miotics into glaucomatous eyes may be followed by an increase in the tonographically calculated coefficient of aqueous outflow, together with lowering of intra-ocular pressure. Although there is a well-accepted clinical grading of the various miotics by "strength" from pilocarpine at the lower end to the powerful cholinesterase inhibitors at the upper, our knowledge is still surprisingly scanty regarding exact dose-response relationships. The study here described was set up to discover whether pilocarpine 2 per cent. used three times a day or echothiophate iodide 0 12 per cent. used once at night, gave different tonographic and tonometric values on the same eyes. Materials and MethodThe clinical material consisted of 11 patients (18 eyes) suffering from open-angle (chronic simple) glaucoma. All had been under observation for a minimum period of three months and had been subjected to the usual investigations: general ophthalmological examination, gonioscopy, applanation tonometry, and visual field studies. Only wide-angle cases were admitted and none of the eyes studied had been subjected to any form of ocular surgery.The apparatus used in the study was the Haag Streit 900 slit-lamp with applanation tonometer and the Schwarzer electronic tonometer with recorder. Each patient was treated with pilocarpine 2 per cent. drops three times daily, and was instructed to instil one drop in each eye at 8.00 a.m., 4.00 p.m., and 10.00 p.m., and after a minimum period of one week on this therapy applanation tonometry and tonography were carried out. The time of day at which this examination was made varied from patient to patient.Pilocarpine therapy was then changed to echothiophate (Phospholine) iodide 0-12 per cent., one drop in each eye every night at 10.00 p.m. One week later applanation tonometry and tonography were again carried out in each case at the same time of day as upon the first occasion.Tonography results were recorded in the rigidity-corrected form by the graphic method of Moses and Becker (1958).