title: The Fluctuation of Intraocular Pressure Measured by a Contact Lens Sensor in Normal-Tension Glaucoma Patients and Nonglaucoma Subjects.
abstract: OBJECTIVE
  We compared the fluctuation of intraocular pressure (IOP) in normal-tension glaucoma (NTG) patients and individuals with nonglaucoma eyes. We obtained continuous IOP values using a SENSIMED Triggerfish contact lens sensor.
  
  
  METHODS
  The eyes of 12 nonglaucoma subjects and 14 NTG patients were examined. In all 26 subjects, the IOP fluctuation was measured continuously for 24 hours with a contact lens sensor. We evaluated the range of IOP fluctuations over the 24-hour period separately for diurnal IOP and nocturnal IOP and identified each subject's maximum value. The range of IOP fluctuation were analyzed, cutoff level of IOP fluctuation was calculated using receiver operating characteristic curve analyses.
  
  
  RESULTS
  The mean IOP in the NTG eyes was 11.5±2.4 mm Hg and that in the nonglaucoma eyes was 12.7±2.0 mm Hg, a nonsignificantly difference (P=0.175). The 24-hour range of IOP fluctuations in the NTG group was significantly larger than that of the nonglaucoma group (P=0.007). The percentage of NTG patients who had the peak time of IOP fluctuation during nocturnal sleep was 57.1%, whereas the corresponding rate for the nonglaucoma eyes was 91.7%. The cutoff level of IOP fluctuation for glaucoma was 442 mVeq (sensitivity=1.00; specificity=0.571).
  
  
  CONCLUSIONS
  The range of IOP fluctuation was larger in the eyes with NTG than in the nonglaucoma eyes. This larger fluctuation might be one of the reasons underlying the aggravation of the visual field by NTG. Measurements of 24-hour continuous IOP might be one of the useful methods to distinguish NTG from nonglaucoma eyes.
authors.affiliation: Department of Ophthalmology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Tojo
authors.forename: Shinya
authors.initials: S
authors.lastname: Abe
authors.forename: Masaaki
authors.initials: M
authors.lastname: Ishida
authors.forename: Takaaki
authors.initials: T
authors.lastname: Yagou
authors.forename: Atsushi
authors.initials: A
authors.lastname: Hayashi
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D002940:Circadian Rhythm / Q000502:physiology; D003261:Contact Lenses; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D057066:Low Tension Glaucoma / Q000175:diagnosis / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012890:Sleep / Q000502:physiology; D014065:Tonometry, Ocular / Q000295:instrumentation*; D014794:Visual Fields / Q000502:physiology