Goldmann applanation tonometry (GAT) has been the gold standard for intraocular pressure (IOP) measurement since its appearance in clinical practice almost 50 years ago.¹ Despite being relatively unchallenged, the last few years have become a continuous search for a new standard method for IOP measurement, mainly for the following three reasons.

1. The demonstrated dependence of GAT accuracy on corneal biomechanics, curvature and thickness.^2–4

2. The advent of refractive surgery procedures has exponentially increased the number of postsurgical eyes on which GAT has been widely proved to be inaccurate.^3,5

3. The need for topical anaesthesia to take measurements, mainly in those practices where non-medical personnel are involved in IOP measurement.

Non-contact tonometry seemed to overcome the need for corneal anaesthesia, as well as facilitating the IOP measurement procedure. A series of devices have been marketed and are currently being used in several practices as the default screening test for IOP. Studies comparing the values obtained with pneumotonometry against GAT have shown that the results are comparable when measuring normal eyes⁶ versus those with glaucoma.⁷ New pneumotonometers even account for the cardiac pulse, detecting it and firing at the same point of the cycle, minimising the variability of the measurements^8,9 However, pneumotonometry readings are still affected …