Abstract
Purpose:
To investigate the relationship between 24-hour intraocular pressure (IOP) related pattern as measured by repeated tonometry and recording with a contact lens sensor (CLS) in patients with primary open angle glaucoma (POAG).
Methods:
A single center, prospective, randomized, controlled, open, crossover observational study was designed to investigate the relationship between the IOP-related pattern. IOP was as measured every 2 h for 24 h using Goldmann applanation tonometry in the sitting position and during the night in supine position using Perkins tonometry. A contact lens sensor (CLS), that measures spontaneous dimensional changes of the eye at the corneoscleral area (SENSIMED Triggerfish®, Sensimed, Switzerland), was used to record the IOP-related pattern for 24 h in the habitual position. Following baseline examination, patients with POAG were hospitalized for 48 hours. Eyes were randomized to tonometry and CLS for the first session (S1) and the reverse for S2 on the subsequent day. Relationships between TM and CLS were computed within each patient separately and summarized over all patients.
Results:
Eleven eligible patients were analyzed with a mean age of 70.3±7.8 years (33.3% female). Mean baseline GAT IOP was symmetric for both eyes for both sessions (S1: 14.9±3.4 and 14.5±2.4 mmHg; S2: 15.6±3.1 and 13.8±2.4). The Pearson correlations between eyes were significant, r=0.72 for the mean 24-hour tonometric IOP pattern and r=0.94 for the CLS IOP-related patterns. The mean 24-hour IOP in S1 (14.3±2.6 mmHg) was not significantly different from that in S2 (12.9±1.4 mmHg). The mean IOP ranged from 5-24 mmHg for S1 and 5-29 mmHg for S2. The amplitude of the cosine function of the CLS output was 63.9 mV with an acrophase at 05:20 am in S1 and was 75.3 mV with acrophase at 07:02 am in S2.
Conclusions:
The low number of tonometry sampling points, that were not always accurately on time, and the use of different tonometers during 24 hours may have impacted the results. The reliability of the CLS output may exceed that of tonometry given the moderate correlation for tonometry between eyes as compared to the high correlation for the CLS output.
Keywords: 568 intraocular pressure