Equipment: iCare tonometer rebounds forward

Most readers will have come across the iCare rebound tonometer by now. Indeed, it has become the standard tonometer for domiciliary care and for some specialist clinics, such as when assessing people with severe learning or behavioural difficulties, such as autism. I first tried out the instrument five years ago and, somewhat to my surprise, found it easy to use and repeatable. (1)

The technique was developed in Finland and relies on electronic conversion of the speed of a metal rod as it passes through a solenoid after being bounced from a cornea at which it has been fired with a constant force. (2) The higher the intraocular pressure, the greater the force of the rebound. Many initial studies were based on animal assessment, and indeed a version for vets, the TonoVet, has been designed.(3)