Negative findings on the seven-minute coefficient of outflow

Gerald L. Portney, Francis Joseph Sousa

Research output: Contribution to journalArticlepeer-review


Efforts have been made to improve the capability of tonography in differentiating normal from glaucomatous eyes. Leydhecker proposed that the quotient P3 C(3-7), obtained from a seven-minute tonographic test, was more reliable for this purpose than any other mathematic value. To test this hypothesis, 152 normal, ocular hypertensive, and glaucomatous eyes were subjected to this seven-minute procedure. With the aid of computer processing, P0, P3, P0 C(0-4), P3 C(3-7), and P0 C(0-7) were obtained. Analysis of data indicated that P0 C(0-4) was significantly more sensitive than the other statistics. In addition, results of this study compared favorably with Becker's work on the distribution of C(0-4) and P0 C(0-4) between normal and glaucomatous populations.

Original languageEnglish (US)
Pages (from-to)848-851
Number of pages4
JournalAmerican Journal of Ophthalmology
Issue number5
StatePublished - 1974

ASJC Scopus subject areas

  • Ophthalmology


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