Page 14 - 21st Century Perspective - Glaucoma Supplement

Assessing After-Hours IOP

It is well established that many, if not most, patients sustain their highest intraocular pressure
readings outside of office hours. Until April 2017, there was no instrument with which a patient could

check his or her own IOP in the comfort of home. Thankfully, the rebound Icare tonometer that has
gained widespread use in eye doctors’ offices has been reconfigured to allow patients to measure
their own eye pressures via the Icare HOME tonometer ​(Figure 8)​. Neither the in-office instrument
nor the Icare HOME tonometer requires anesthesia, as the testing/measurement procedure is
painless.

Figure 8.​ Icare HOME tonometer.

Many patients who develop glaucomatous optic neuropathy never show an IOP above 21 mm Hg

during office hours (this is often categorized as low-tension or normal-tension glaucoma), but how
many of these patients actually have IOPs above 21 mm Hg after office hours? We now have the
technology to determine more of the true nature of patients’ IOP behavior.

In some patients, glaucomatous atrophy progresses despite apparently controlled IOP, based on
in-office readings; however, it may well be that these patients experience higher (and as yet
undetected) IOPs outside of regular office hours. Now, with rebound tonometry for in-home use, we

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