Abstract
Purpose :
Diurnal IOP variation is well-known. The exact pattern of circadian IOP fluctuation in glaucomatous patients remains debatable. This prospective observational study is to evaluate the 24-hour pattern of IOP changes in patients with glaucoma measured with a contact lens sensor (CLS) and to compare the variation between CLS and tonometry.
Methods :
The eyes of 24 glaucomatous patients (9 females, 15 males) were examined for diurnal IOP fluctuations for 24 hours with Sensimed Triggerfish® CLS while they carry out their normal activities. The 24-hour period was divided into eight 3-hour time slots (0000-0259, 0300-0559, 0600-0859, 0900-1159, 1200-1459, 1500-1759, 1800-2059, 2100-2359) and the peak and trough values of IOP with their corresponding time slots were recorded. The coefficient variation of mean average of peak and trough value of CLS data and mean average of IOP measured using Goldmann applanation tonometry (GAT) in clinics were compared.
Results :
All patients successfully completed the 24-hour measurement of IOP with CLS safely with no adverse reactions.
The mean patient age was 69.83 (SD: 7.8) years. 15 (62.5%) were left eyes.
13 subjects (54.1%) showed early morning peak.
12 (50%) subjects have their peak IOP at 0600-0859 period, mean peak value was 319.6 mVeq (SD: 174.6). 18 (75%) subjects have their trough IOP at 2100-2359 period, mean trough value was -113.3 mVeq (SD: 123.1). The mean peak and trough average of CLS data was 216.4 mVeq (SD: 77.6) whilst the mean average of IOP value was 16.6 mmHg ( SD: 3.02). The coefficient of variation of CLS value was 35.9%. The coefficient of variation of IOP measured by GAT was 18.2%.
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Conclusions :
The most common circadian IOP pattern was early morning acrophase. Most glaucomatous patients had highest IOP in the morning which coincides with the circadian cortisol peak. These peaks can be missed by the contemporary practice of IOP measurement during daytime clinic hours. The coefficient variation of CLS value was higher than the IOP in daytime IOP clinic measurements. The impact of dimensional corneal curvature change and the standardisation of units of measurement by GAT & CLS needs evaluation. CLS has the potential of supplementing or replacing phasing, better study the therapeutic 24 hour response to medications, laser, surgery & analyse "low" or "normal" pressure glaucoma cases.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.