title: Circadian pattern of intraocular pressure fluctuations in young myopic eyes with open-angle glaucoma.
abstract: OBJECTIVE
  To characterize the circadian pattern of habitual-position intraocular pressure (IOP) and its association with ocular dimension in young myopic patients with open-angle glaucoma (OAG).
  
  
  METHODS
  A total of 108 young OAG patients with moderate to severe myopia (myopia group) and 67 age-matched OAG patients with emmetropia or mild myopia (control group) were recruited prospectively over 3 years. IOP was recorded 11 times over a 24-hour period by a single, well-trained ophthalmology resident using a handheld tonometer.
  
  
  RESULTS
  A total of 87 men and 88 women were included in this study. Analysis of the entire myopia group indicated no acrophase in habitual-position IOP over 24 hours. Subgroup analysis indicated that 44 patients (40.7%) had a diurnal acrophase, 17 patients (15.7%) had a nocturnal acrophase, and 47 patients (43.6%) had no evident acrophase. By contrast, the control group showed an overall nocturnal acrophase in habitual-position IOP, with 14 patients (20.8%) having a diurnal acrophase, 30 patients (44.8%) having a nocturnal acrophase, and 23 patients (34.4%) having no evident acrophase in subgroup analysis. There was a negative correlation between nocturnal habitual-position IOP elevation and axial length in the overall population.
  
  
  CONCLUSIONS
  In young myopic OAG eyes, there is no significant nocturnal elevation in habitual-position IOP, while IOP increases at night-time in age-matched control eyes. The overall 24-hour IOP pattern in the myopia group did not show an acrophase. Finally, data showed a negative relationship between nocturnal habitual-position IOP elevation and axial length.
authors.affiliation: Department of Ophthalmology, Asan Medical Center, Division of Biostatistics, Center for Medical Research and Information, University of Ulsan, College of Medicine, Seoul, Korea.
authors.forename: Da Woon
authors.initials: DW
authors.lastname: Jeong
authors.forename: Michael S
authors.initials: MS
authors.lastname: Kook
authors.forename: Kyoung Sub
authors.initials: KS
authors.lastname: Lee
authors.forename: Jong Rak
authors.initials: JR
authors.lastname: Lee
authors.forename: Seungbong
authors.initials: S
authors.lastname: Han
mesh_terms: D000293:Adolescent; D000328:Adult; D002940:Circadian Rhythm; D005260:Female; D005500:Follow-Up Studies; D005902:Glaucoma, Open-Angle / Q000150:complications / Q000503:physiopathology*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000150:complications / Q000503:physiopathology*; D011446:Prospective Studies; D014065:Tonometry, Ocular; D055815:Young Adult
keywords: circadian pattern; glaucoma; intraocular pressure; myopia