A Comparison of Tonography and Suction

Abstract

The technique of perilimbal suction cup analysis has been employed primarily to assess aqueous flow.¹When the cup is applied to the eye, intraocular pressure rises if aqueous secretion continues and if there is little or no loss of this fluid from under the cup. The pressure increment is caused by the aqueous entering the eye and reflects the secretion rate for the study period. When the cup is removed after 15 minutes of suction, intraocular pressure will decay at a rate somewhat dependent on the outflow facility of the eye. Consequently, measuring the percentage pressure return to presuction levels for a given time interval affords a simple, qualitative estimate of outflow resistance.^2,3 To test the efficacy of percentage pressure decay as a measure of outflow resistance, the results of tonographic analysis and perilimbal suction cup analysis were compared in the same patients. Further, the influence of miotic