title: Diurnal variation of intraocular pressure in suspected normal-tension glaucoma.
abstract: OBJECTIVE
  To assess diurnal variations of intraocular pressure (IOP) in suspected normal-tension glaucoma (NTG) patients with subsequent long-term observation to detect changes that may lead to a new diagnosis.
  
  
  METHODS
  Diurnal variation of IOP was measured in a sitting position at 2-h intervals for 24 h in a total of 569 subjects with suspected NTG.
  
  
  RESULTS
  Thirty of the 569 subjects (5.3%) showed IOP values exceeding 20 mmHg during the 24-h monitoring and were diagnosed as having primary open-angle glaucoma (POAG). In subjects in whom NTG was definitely diagnosed based on the results of the 24-h monitoring, the average maximum, minimum, and mean IOP was 16.1, 11.7, and 13.9 mmHg, respectively, and the mean diurnal variation in IOP was 4.4 mmHg. The peak time was observed outside clinic hours (1800-0800) in 41.4% of patients, and the trough time was observed during clinic hours (1000-1600) in 15.9%. In 2.9% of NTG subjects, the diagnosis was eventually changed to POAG during follow-up.
  
  
  CONCLUSIONS
  Assessment of diurnal variations of IOP in suspected NTG patients is useful for the differential diagnosis of POAG from NTG and for establishment of a baseline, which may affect the management plan.
authors.affiliation: Department of Ophthalmology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Kou
authors.initials: K
authors.lastname: Hasegawa
authors.affiliation: Department of Ophthalmology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Ishida
authors.affiliation: Department of Ophthalmology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Sawada
authors.affiliation: Department of Ophthalmology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Kazuhide
authors.initials: K
authors.lastname: Kawase
authors.affiliation: Department of Ophthalmology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Yamamoto
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D005902:Glaucoma, Open-Angle / Q000503:physiopathology*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D013997:Time Factors; D014065:Tonometry, Ocular / Q000379:methods