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HomeminewsPatient Self-tonometry in Glaucoma Management

Patient Self-tonometry in Glaucoma Management

Patient involvement is increasingly being used in the management of systemic chronic, progressive disorders, such as diabetes. One of the advantages with the introduction of contemporary, patient-centred health care concepts is the increasing patient knowledge regarding their risks and conditions. Appropriate guidance by the consulting clinician can then direct the patient to contribute to their ongoing management, which, in turn, elicits better compliance with preventative or interventional actions.

Integration into eye health care, however, has been challenged by the large diversity in conditions and highly specialised instrumentation reserved for the appropriately trained clinician.

Monitoring intraocular pressure (IOP) is an integral part of routine glaucoma assessment and pivotal for glaucoma management. The introduction of the Icare HOME instrument in 2014 is providing an opportunity to involve patients in their ongoing IOP measurements and provide the overseeing clinician with adjunct clinical information relevant to optimise individualised eye health care.

IOP Phasing Through Self-Tonometry

elevated IOPs were identified outside office hours in approximately 50 per cent of patients phased with the Icare HOME over four to six weeks

Since the development of applanation tonometry, IOP measurement using the Goldmann tonometer has been considered the gold standard in ophthalmic practice. Clinicians actively involved in glaucoma management are well versed in the use of the instrument, but clinical acumen commonly must rely on a comparatively small number of measurements taken during patient visits.

By doing so, diurnal fluctuations, including peak IOPs outside office hours may go unnoticed for extended periods of time. Furthermore, standard clinical practices do not capture the long established individual variability with these fluctuations,1 or impact of daily activities (e.g. postural position, playing wind instruments etc).

Both routine 24-hour IOP monitoring, typically conducted within a hospital setting, or extensive daytime phasing in an outpatient setting, are time consuming and often impractical. In the face of sometimes significant day-to-day variability with IOP fluctuations, information obtained on a single day may still not provide a comprehensive picture of a patient’s true changes in IOP.

At the Centre for Eye Health (CFEH), elevated IOPs were identified outside office hours in approximately 50 per cent of patients phased with the Icare HOME over four to six weeks.2 Patients appropriately trained to use the instrument obtained multiple measurement each day over extended periods of time, alleviating the need for tedious in-practice phasing. More importantly, excessive IOP fluctuations, not otherwise indicated from clinical data, warranted changes to the management in up to 10 per cent of patients.

Patient Self-Tonometry in Clinical Practice

It has already been established that self-tonometry with the Icare HOME is well accepted by patients and approximately 75-80 per cent can successfully be trained. Several recent studies support the reliability and utility of rebound tonometry. Although not directly comparable, IOP measurement obtained with the Icare HOME show generally good correlation to Goldmann applanation tonometry.3 The resulting long-term data can therefore provide valuable complimentary information to standard in-clinic assessments.

The recent study by Huang et al.2 specifically highlights that a single week of Icare HOME self-monitoring is a good indicator of a patient’s predominant diurnal long-term pattern with as few as four daily measurements. The authors further demonstrate that self-monitoring can assist to establish the initial effect of treatment within a day. The potential to recognise unwarranted IOP fluctuations, despite seemingly effective treatment, may reduce the number of patients with otherwise clinically unexplained glaucoma progression.

Given these results, CFEH, associated with the University of New South Wales, in Sydney has now integrated one-week Icare HOME IOP phasing as part of its ongoing glaucoma management for appropriate patients with, or who are at risk of developing glaucoma, and is offering the service to referring clinicians.

While the long-term utility of IOP self-monitoring for glaucoma management remains to be evaluated, it can be expected that it will positively affect individual outcomes.

Dr. Barbara Zangerl DVM, PhD has developed an internationally recognised research career exploring the underlying causes and potential cure for blinding disorders. Dr. Zangerl works at the Centre for Eye Health focusing on clinical investigations of glaucoma.

1. David R, Zangwill L, Briscoe D, Dagan M, Yagev R, Yassur Y. Diurnal intraocular pressure variations: an analysis of 690 diurnal curves. British Journal of Ophthalmology 1992;76:280-283.
2. Huang J, Katalinic P, Kalloniatis M, Hennessy MP, Zangerl B. Diurnal intraocular pressure fluctuations with self-tonometry in glaucoma patients and suspects: a clinical trial. Optometry and Vision Science 2018;95(2):88-95.
3. Mudie LI, LaBarre S, Varadaraj V, Karakus S, Onnela J, Munoz B, Friedman DS. The iCare HOME (TA022) Study: Performance of an intraocular pressure mearusing device for self-tonometry by glaucoma patients. Ophthalmology 2016;123:1675-1684.