A tool, widely regarded as the "gold standard," but often deemed to be too expensive, cuts needless referrals for suspected glaucoma, indicates preliminary research published online in the British Journal of Ophthalmology.
Since the publication of new guidance from the National Institute for Health and Clinical Excellence (NICE), new referrals for suspected glaucoma have increased substantially. And this is likely to go on rising as the population ages, warn the authors. If left untreated, glaucoma causes blindness.
This sharp rise in referrals is putting a strain on hospital eye services, bumping up costs, and causing unnecessary distress for patients, say the authors.
But not all of these people would need to be referred if a more selective, but inevitably more expensive, piece of kit were used to test for glaucoma.
The researchers assessed how many referrals for suspected glaucoma - internal (intraocular) fluid eye pressure of over 21 - could be avoided if the Goldmann applanation tonometer (GAT) were used for all patients.
High intraocular pressure is a key sign of glaucoma, and is measured by the amount of pressure needed to flatten the surface of the eye (cornea).
NICE recommends GAT, but other options are frequently used instead by community optometrists, because they are cheaper and don't require the use of anaesthetic eye drops.
Over a period of five months, people with intraocular pressures of between 22 and 25, measured with other tonometers, and with no other symptoms of glaucoma, were assessed again using GAT.
Out of 3,295 people assessed at four community optometry services during this time, 73 (2.2%) had a high intraocular pressure. They would normally have been referred to the hospital eye service for further tests.
But when the assessment was repeated using GAT, almost two thirds of this group (46) had intraocular pressures of 21 or below and so did not need to be referred.
"The use of Goldmann applantion tonometry by optometrists, prior to instigating a referral to the [hospital eye service] has huge potential to reduce unnecessary referrals," conclude the authors.