Abstract
Purpose :
Diagnosis and monitoring of glaucoma, a progressive optic neuropathy, is guided by intraocular pressure (IOP). With current standards of practice, IOP is typically measured during office hours at single time points hence IOP fluctuations occurring outside these hours are not detected. We performed a controlled clinical trial to investigate the extent of diurnal intraocular pressure variations in glaucoma patients utilising a novel self-administered rebound tonometry instrument.
Methods :
40 patients were recruited following standard glaucoma-related examination at Centre For Eye Health in Sydney, Australia. Exclusion criteria included active ocular surface disease, significant ocular malformations or abnormalities that precluded use of the instrument. Participants underwent training and certification to use the Icare® HOME tonometer, as specified by the manufacturer which included obtaining 5 reliable baseline measurements. Upon successful completion, the tonometer was provided with instructions to perform IOP testing four times a day, over a six week period. Participants with newly diagnosed glaucoma initiated topical anti-glaucoma treatment within 24 hours of recruitment. Paired t-test was used to examine differences between groups.
Results :
35 participants have completed the trial to date. 8 failed certification and 3 did not complete data collection. Preliminary analysis of 24 patients, with a mean age of 60.2 years (SD 8.2) obtained a total 129 measurements each (equivalent to 4 measurements per day). Comparison of the glaucoma group (n=8) and the non-glaucoma group (n=16) showed significantly different IOP measurements at baseline, 26.7mmHg (SD 2.5) versus 17.3mmHg (SD 1.4) respectively (p<0.01). However, IOPs were not significantly different across the 6-week period at 14.4mmHg (SD 4.0) and 15.3mmHg (SD 1.5) following treatment initiation for the glaucoma group. Diurnal fluctuations in the patients showed a median range of 14mmHg (excluding the effect of treatment), with the peak IOP occurring at different times across individuals.
Conclusions :
Patient-administered tonometry may provide clinicians greater insight into IOP fluctuations particularly in patients who exhibit peak IOP outside normal office hours. Observation of IOP changes following commencement of treatment will allow further establishment of treatment-to-response time intervals.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.