To the Editor.
—I read with interest the article by Gerald L. Portney and Marijane Krohn, "Tonography and Projection Perimetry," which appeared in the August 1977 issue of the Archives (95:1353-1356, 1977). The results were very similar to my observations when I compared the tonography values of glaucomatous eyes with the outflow coefficients of ocular hypertensives without glaucomatous optic nerve damage. The point of disagreement is the conclusion.Portney and Krohn state that tonography is useful in identifying those eyes that need close observation for the development of glaucomatous change. I cannot find in their report evidence that supports this view.I believe that the tonographic difference between the glaucomatous patients and the normotensive population has not much clinical value. The important result is that the distinction between glaucomatous eyes and hypertensive eyes without glaucoma cannot be made with tonography.When the intraocular pressure is measured several times, the additional
Pohjanpelto P. The Value of Tonography. Arch Ophthalmol. 1978;96(4):729. doi:10.1001/archopht.1978.03910050407025