There is no report in the literature on the relationship of the weight of the Schiotz tonometer footplate to scale reading. That there is a relationship is the subject of this report.
Eye Bank eyes were cannulated through the posterior chamber, the cannula tip then passing into the pupil. The cannula was connected to an open saline reservoir of large capacity. The head of a Mueller electronic tonometer was fixed to one arm of a balance. Variation of footplate weight was accomplished by weighting the pan on the other balance arm (Fig 1). The saline reservoir was set at 40 cm above the limbus. The 7.5 gm plunger load was employed in all experiments. Six eyes were used.
Open manometer scale reading increases with footplate weight at a rate of about 0.3 scale units per gram. The results are summarized in Fig 2.
Kronfeld1 noted that
MOSES RA. Tonometer Footplate Weight and Scale ReadingOpen Manometer Studies. Arch Ophthalmol. 1964;71(5):691-692. doi:10.1001/archopht.1964.00970010707017