Comparison Between the NCT and Mackay‐marg Tonometer

The Mackay‐Marg electronic tonometer is generally regarded as an applanation tonometer of high clinical accuracy and has been used for obtaining correlations with other tonometers on a number of occasions. Concerning the correlation between the Mackay‐Marg tonometer and the recently introduced Non‐Contact‐Tonometer (NCT) no results have yet been published. In this study 58 patients had their eyes measured by both NCT and Mackay‐Marg tonometry. All the measurements were performed without the use of anesthesia. A close relationship between the readings from the two tonometers was found. Pearson's coefficient of correlation is +0.87, which suggests that the NCT is accurately assessing the same function as the Mackay‐Marg tonometer, i.e. the IOP. The mean of the Mackay‐Marg readings was 18.48 and the standard deviation 3.52, and that of the NCT was 17.38 and the S.D. 3.84. The criteria for reference seem to be similar in NCT and Mackay‐Marg Tonometry.