The Keeler Pulsair air impulse tonometer. Comparison with the Perkins hand-held applanation tonometer for peri-operative measurement of intra-ocular pressure.

Abstract

The Keeler Pulsair is a noncontact tonometer which can be used by those without specialist ophthalmic training. The instrument was compared, in a series of 30 patients in whom a total of 150 readings were taken, in respect of accuracy, ease and speed of use, and acceptability to patients, with the Perkins hand-held applanation tonometer. There was good correlation between measurements obtained with the two instruments: r = 0.92, (p less than 0.001); the Pulsair was described as easy to use in 87% of subjects, and no patient found the procedure unpleasant. The median times taken for Pulsair measurements were 7 (range 4-14) seconds for a single reading in conscious patients, and 11 (range 4-29) seconds for four readings in anaesthetised patients. These times were significantly quicker than those recorded with the Perkins tonometer which were 83 (range 66-138) seconds and 20 (range 8-45) seconds respectively (p less than 0.001). We conclude that the Pulsair is suitable for use by those who are not ophthalmologists for the rapid measurement of intra-ocular pressure changes during anaesthesia.