Bulbar pressure test in glaucoma.

THIS paper describes a relatively simple clinical test devised to estimate the facility of outflow of aqueous from an eye while external pressure is being applied to the globe; such a test is obviously of value in the investigation of cases of glaucoma. The fact that it is possible to reduce the tension in the eye by massage has been known for many years, and interest in the subject was revived during the latter part of the 19th century, when the invention of the tonometer enabled changes in the intra-ocular pressure to be measured with some degree of accuracy. Schiotz (1908) himself noted that if the tonometer were left too long on the eye the tension was reduced, and Polak-van Gelder (1911) stated that this fall in tension was due to the expression of aqueous from the eye, and that its magnitude depended on the ease with which the aqueous could escape. She also stated that a greater amount of massage was necessary to produce the same fall in tension in glaucomatous as in normal eyes, and she appears, in fact, to have been the first person to use massage with a tonometer as a diagnostic test. Since then numerous attempts have been made to develop the potentialities of this technique, but, though manyworkers agreed that in general the pressure did not fall so much in glaucomatous eyes, especially those which were already in a state of increased tension, they were unable to produce a standard minimal fall in tension below which limit an eye can be considered abnormal. Thomassen (1946) studied the effects of compressing the eye with various weights. Although he found that eyes with advanced glaucoma were not so easily compressed, he came to the conclusion that it was not possible by this method to detect any significant difference between the fall produced in normal eyes and that in glaucomatous eyes with normal tension. Consequently, most of his work was devoted to the study of the secondary rise in tension that occurs after compression. His monograph includes a very comprehensive review of all the previous work done on this subject. Moses and Bruno (1950) studied the fall in tension produced by leaving an electric tonometer on the eye for 2 minutes, and stated that the rate of