Abstract
Purpose: :
To investigate if patients with open-angle glaucoma and an intraocular pressure (IOP) below the target IOP during office hours exceeded the target IOP during a diurnal curve with the iCare ONE home tonometer. To compare the IOP fluctuations between glaucoma patients and normal controls.
Methods: :
In this prospective study, 34 subjects were included: 21 patients with open-angle glaucoma and an IOP below the target during office hours, and 13 age-matched normal controls with an IOP < 21 mmHg. Exclusion criteria were: age < 18, pathology of the cornea or impossibility/unwillingness to use the home tonometer. Only the right eye was included unless the left eye was the only one progressing. During the inclusion visit, the IOP was measured with the Goldmann applanation tonometer (GAT) in the glaucoma patients. Corneal thickness was measured with the Pachmate DGH 555 in all subjects. All subjects measured their IOP using the iCare ONE home tonometer during 7 days, 4 times per day (8-9 AM, 12-1 PM, 5-6 PM and 10-11 PM). After 7 days the home tonometry measurements were downloaded electronically for each subject. The accuracy of each iCare ONE home tonometer was tested before the study on a different group of patients: all measurements with the home tonometers were within the GAT measurements ±3 mmHg. Within-week and within-day fluctuations were expressed as within-subject standard deviations (SD), obtained with a linear mixed model. SDs were compared between patients and normal controls using a likelihood-ratio test.
Results: :
The mean ±SD GAT of the glaucoma patients at inclusion was 12.45 ±3.05 mmHg. The mean ±SD pachymetry of the glaucoma patients and the normal controls was 541.4 ±46.1 µm and 556.5 ±45.9 µm respectively (p = 0.53).Nineteen out of 21 glaucoma patients had a pre-determined target IOP. The mean target IOP was 14.5 mmHg (range 12-19 mmHg). Sixteen out of the 19 patients (84%) had at least one measurement above the target IOP. The target IOP was exceeded with > 3 mmHg (up to 12 mmHg) at least twice in 10/19 patients (53%), without specific time pattern.The long-term (within 7 days) IOP fluctuations for glaucoma patients and normal controls were 3.07 and 3.16 mmHg respectively (p = 0.58). This fluctuation was almost completely explained by the short-term (within 1 day) fluctuation (2.93 mmHg and 3.09 respectively, p = 0.39).The mean IOP was highest between 5-7 PM in the glaucoma group and between 8-9 AM in the normal group.
Conclusions: :
Diurnal curves with the iCare ONE home tonometer can be useful in patients with progressing glaucoma despite IOPs below the target during office hours.
Clinical Trial: :
http://www.clinicaltrials.gov B322201111826
Keywords: intraocular pressure • clinical (human) or epidemiologic studies: risk factor assessment • clinical (human) or epidemiologic studies: systems/equipment/techniques