Use of Water-Drinking Tonography in Mass Screening for Glaucoma*

The results of mass screening for glaucoma of workers in a factory in Chiba Prefecture, Japan, are reported. At the first-stage examination, tonometry was performed with standardized Schiøtz tonometers on 1,527 subjects (3,054 eyes) with no ocular symptoms. When the tension was 5.0/5.5 gm or higher, the patient was regarded as a preliminary suspect and a detailed ophthalmologic examination was recommended. The second-stage examination, in the University Clinic included campimetry, vision tests, water-drinking tonography, tonometry with applanation and Schiøtz tonometers, funduscopy and gonioscopy. Of the 239 (381 eyes) preliminary suspects, 79 came to the Clinic for the second-stage examination. Water-drinking tonography, done on 104 eyes with tension of greater than 5.0/5.5 gm, revealed that 48 had a Po/C ratio greater than 100, which strongly suggests the presence of glaucoma. In water-drinking tonography, a Po/C ratio greater than 100 was noted in about 34% of 58 eyes with a tension of 4.25/5.5-5.0/5.5 gm, suggesting that the index for separating glaucoma suspects from normals could be brought down to the level of 5.0/5.5 gm. The over-all percentage of glaucoma cases found was 1.3%. The efficacy of water-drinking tonography in mass screening for glaucoma has been discussed.