title: Twenty-four hour blood pressure pattern in patients with normal tension glaucoma in the habitual position.
abstract: OBJECTIVE
  To investigate the relationship between blood pressure (BP) parameters in the habitual position and glaucomatous damage at initial presentation in patients with untreated normal tension glaucoma (NTG).
  
  
  METHODS
  Fifty-four eyes from 54 subjects diagnosed with NTG were consecutively enrolled. BP was measured with an automated ambulatory monitoring device in the habitual position during 24-hour in-hospitalization. Patients were classified into three groups: non-dippers, dippers, and over-dippers. corresponded to the degree of reduction in their nocturnal mean arterial pressure (MAP) compared with their diurnal MAP. Regression models were used to evaluate potential risk factors, including: age, pre-admission office intraocular pressure (IOP), central corneal thickness (CCT), and BP parameters. Functional outcome variables for glaucomatous damage included mean deviation (MD) and pattern standard deviation (PSD) on a Humphrey field analyzer (HFA). Anatomic outcome variables were TSNIT score (temporal, superior, nasal, inferior, and temporal) average, superior average, inferior average, and nerve fiber indicator (NFI) score on scanning laser polarimetry with variable corneal compensation (SLP-VCC; GDx-VCC).
  
  
  RESULTS
  Marked systolic blood pressure (SBP), diastolic blood pressure (DBP), and MAP fluctuation were noted in the over-dipper group (p<0.05). A linear regression analysis model revealed that nocturnal trough DBP and MAP, average nocturnal SBP, and MAP were all significantly associated with a decreased average TSNIT score and an increased NFI score.
  
  
  CONCLUSIONS
  Nocturnal BP reduction estimated in the habitual position was associated with structural damage in eyes with NTG. This finding may suggest systemic vascular etiology of NTG development associated with nocturnal BP reduction.
authors.affiliation: Department of Ophthalmology, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Korea.
authors.forename: Soo Geun
authors.initials: SG
authors.lastname: Joe
authors.forename: Jaewan
authors.initials: J
authors.lastname: Choi
authors.forename: Kyung Rim
authors.initials: KR
authors.lastname: Sung
authors.forename: Seong Bae
authors.initials: SB
authors.lastname: Park
authors.forename: Michael S
authors.initials: MS
authors.lastname: Kook