Tonometry through the lid : The Diaton

It is some years since we reported on a tonometer from Russia which could measure IOP by the application of force to the upper eye lid. It was being marketed in Spain and Germany at the time but never made it to the UK. After some development and re-design, Weco is now lauching the Diaton in the UK. It is a novel design and I was lucky enough to use it at the City University clinic recently.

Indentation

In principle, the Diaton is more akin to an indentation tonometer than an applanation technique. A small piston is shot onto the closed eye and the resistance to the force offered by the closed lid to the piston is converted into a pressure reading. This clearly meets with some concerns which I shall mention later, but the way in which the instrument is operated is unique enough for a fuller description.