title: Automated Detection and Quantification of Circadian Eye Blinks Using a Contact Lens Sensor.
abstract: OBJECTIVE
  To detect and quantify eye blinks during 24-hour intraocular pressure (IOP) monitoring with a contact lens sensor (CLS).
  
  
  METHODS
  A total of 249 recordings of 24-hour IOP patterns from 202 participants using a CLS were included. Software was developed to automatically detect eye blinks, and wake and sleep periods. The blink detection method was based on detection of CLS signal peaks greater than a threshold proportional to the signal amplitude. Three methods for automated detection of the sleep and wake periods were evaluated. These relied on blink detection and subsequent comparison of the local signal amplitude with a threshold proportional to the mean signal amplitude. These methods were compared to manual sleep/wake verification. In a pilot, simultaneous video recording of 10 subjects was performed to compare the software to observer-measured blink rates.
  
  
  RESULTS
  Mean (SD) age of participants was 57.4 ± 16.5 years (males, 49.5%). There was excellent agreement between software-detected number of blinks and visually measured blinks for both observers (intraclass correlation coefficient [ICC], 0.97 for observer 1; ICC, 0.98 for observer 2). The CLS measured a mean blink frequency of 29.8 ± 15.4 blinks/min, a blink duration of 0.26 ± 0.21 seconds and an interblink interval of 1.91 ± 2.03 seconds. The best method for identifying sleep periods had an accuracy of 95.2 ± 0.5%.
  
  
  CONCLUSIONS
  Automated analysis of CLS 24-hour IOP recordings can accurately quantify eye blinks, and identify sleep and wake periods.
  
  
  CONCLUSIONS
  This study sheds new light on the potential importance of eye blinks in glaucoma and may contribute to improved understanding of circadian IOP characteristics.
authors: ICT Institute, University of Applied Sciences Western Switzerland, Fribourg, Switzerland.
authors: Christophe
authors: C
authors: Gisler
authors: ICT Institute, University of Applied Sciences Western Switzerland, Fribourg, Switzerland.
authors: Antonio
authors: A
authors: Ridi
authors: ICT Institute, University of Applied Sciences Western Switzerland, Fribourg, Switzerland.
authors: Jean
authors: J
authors: Hennebert
authors: Hamilton Glaucoma Center, Department of Ophthalmology, University of California, San Diego, USA.
authors: Robert N
authors: RN
authors: Weinreb
authors: Glaucoma sector, Department of Ophthalmology, Geneva University Hospitals, Geneva, Switzerland ; Department of Ophthalmology, University of Colorado School of Medicine, Denver, USA.
authors: Kaweh
authors: K
authors: Mansouri
keywords: 24-hour; circadian; contact lens sensor; eye blinks; glaucoma
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