tonography(redirected from carotid compression tonography)
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the recording of changes in intraocular pressure due to sustained pressure on the eyeball.
carotid compression tonography a test for occlusion of the carotid artery by measuring ocular pressure and pulse before, during, and after the proximal portion of the carotid artery is compressed by the fingers.
Continuous measurement of intraocular pressure by means of a recording tonometer to determine the facility of aqueous outflow.
Continuous measurement of intraocular pressure by means of a recording tonometer, to determine the facility of aqueous outflow.
Technique for measuring the facility of outflow of aqueous humour from the eye under the continuous pressure exerted by the weight of a tonometer over a given period of time. The instrument usually employed for tonography is an electronically recording Schiötz tonometer. In this technique, the pressure is continuously recorded over a four-minute period and the outflow is deduced by utilizing a specifically designed diagram, called a nomogram (which is a graphical representation of one, or more, mathematical relationships whereby the desired value may be found without calculation by placing a straight edge across the diagram). The results of tonography can indicate the presence of established glaucoma, although the technique is not very reliable for borderline cases.