Abstract
Purpose:
To evaluate whether information from a contact lens sensor for 24-h monitoring of intraocular pressure (IOP) patterns can be used to distinguish sleep stages. We further hypothesized that IOP patterns may be higher in the rapid eye movement (REM) phase.
Methods:
12 healthy subjects underwent simultaneous ambulatory 24-h monitoring of IOP patterns using a contact lens sensor (CLS; Triggerfish, Sensimed AG, Switzerland) and sleep monitoring using a validated wireless system (WS; ZEO, Newton, MA, USA) that collects electrophysiological signals from the forehead with a single bi-polar channel. The CLS measures ocular dimensional changes at the corneo-scleral junction that are assumed to be related to IOP changes. The WS distinguishes 4 sleep stages: wake, light sleep, deep sleep, REM. Intraclass correlation coefficients (ICC) were calculated for comparison of CLS and WS-derived sleep stages.
Results:
Data on both IOP and sleep stages could be obtained in 10 subjects (mean age 42 ± 10.2 years; 60% women). Four different patterns of CLS-data could be distinguished during sleep: high-frequency sinusoidal pattern, low-frequency sinusoidal pattern, and irregular pattern. The irregular pattern correlated well with the WS-derived REM stage (ICC=0.91), while the other two CLS stages did not correlate well with WS sleep stages (ICC=0.47). IOP patterns during CLS-derived REM stages were higher than during non-REM sleep stages (128 ± 52 mV vs. 108 ± 42; p=0.044).
Conclusions:
Results show a good agreement between CLS and WS recordings of REM sleep. This work further supports a possible use of combined sleep and IOP pattern monitoring in glaucoma patients.
Keywords: 568 intraocular pressure •
522 eye movements