The pressure phosphene tonometer--a clinical evaluation.

Abstract

Pressure phosphene tonometry is said to assess intraocular pressure by inducing a pressure phosphene. This study compared the results of this relatively new technique with Goldmann applanation tonometry. A total of 100 patients (196 readings) in a general ophthalmology clinic at Dunedin Hospital who consented to take part in this study were randomised to receive by different examiners either pressure phosphene tonometry by a Proview eye pressure monitor (Bausch & Lomb Inc., Tampa, FL, USA) or Goldmann tonometry first. There was no communication between the examiners regarding results. Of the 196 attempted readings, pressure phosphene tonometer readings were only able to be obtained for 136 eyes (69%) compared to all 196 (100%) eyes with the Goldmann tonometer. The mean IOPs were 18.5 mmHg using the pressure phosphene tonometer and 16.0 mmHg using the Goldmann tonometer. The mean difference was +2.43 mmHg (95% confidence interval: 10.37 mmHg below to 15.22 mmHg above Goldmann readings). This study found that 31% of patients could not perceive a pressure phosphene using the Proview eye pressure monitor. Data obtained from those who could perceive the phosphene indicated that large discrepancies between pressure phosphene tonometry and Goldmann tonometry were common.