Comparison of a new non-contact tonometer with Goldmann applanation

A comparison of a new non-contact tonometer (Keeler Pulsair: Keeler UK Ltd) with the Goldmann applanation tonometer is reported. Measurements of intraocular pressure were obtained from 182 eyes of 94 patients. At low pressures (less than 10 mmHg) the candidate tonometer tended to overestimate pressures obtained with the Goldmann tonometer whilst at high pressures (greater than 19 mmHg) those obtained by Goldmann applanation were underestimated. Between 10 and 19 mmHg there was no significant difference between readings obtained with either method. Up to 71% of averaged Pulsair measurements fell within +/- 3 mmHg of those obtained with the Goldmann tonometer increasing to 78% if pressures greater than or equal to 30 mmHg obtained with the Pulsair tonometer were excluded. Adopting a screening criterion of greater than or equal to 21 mmHg (Goldmann) resulted in a sensitivity of 85% and a specificity of 95%. Some evidence that serial Pulsair readings are influenced by the ocular pulse is presented. It is concluded that the Pulsair tonometer can provide clinically useful measurements of intraocular pressure.