This paper presents, first, some of the difficulties encountered by us while instituting Grant's method1 of electrical tonography for clinical use and, second, certain control studies done on normal eyes in an attempt to determine the accuracy of the method as employed by us for routine use. The difficulties described are both the technical ones involved in actually setting up our apparatus and those of technique which led to errors in tracings after our apparatus had been assembled. We are discussing some of these pitfalls with the intent of helping others, beginning in tonography, to avoid them.
Once these difficulties had been surmounted and our method of procedure seemed sufficiently reliable, we studied a series of normal eyes, to obtain data on the reliability of tonography as used by us. Recordings were made on the same eye at different times of the same day, and on different days. Likewise,