title: Diurnal variation in microcirculation of ocular fundus and visual field change in normal-tension glaucoma.
abstract: OBJECTIVE
  Diurnal variations in microcirculation of the ocular fundus in normal-tension glaucoma (NTG) were examined to compare with the normal control eyes. The correlation between progression of visual field impairment and diurnal variations in ocular circulation was also studied.
  
  
  METHODS
  The subjects were 12 patients with NTG and 12 normal controls. Blood pressure (BP), intraocular pressure (IOP), ocular perfusion pressure (OPP), and square blur rate (SBR), an index of microcirculation acquired by the laser speckle method, were measured at 9 a.m. (morning), 3 p.m. (afternoon), and 9 p.m. (night). Diurnal variations in SBR were tested using the Friedman test and Wilcoxon signed ranks test. On the other hand, diurnal variations in BP, IOP, and OPP were tested by the analysis of variance. The visual field was evaluated at the same time as determining diurnal variation and again about 9 months later to calculate the change. The correlation between variation ratio in SBR and the change in visual field was examined by simple regression.
  
  
  RESULTS
  A significant decrease (P=0.04) was found in SBR at night, as compared with the morning value, in the optic nerve head (ONH) of NTG, although no significant diurnal variations were found in SBR either in the choroid-retina or in normal control eyes. Other parameters showed no significant diurnal variations. The larger diurnal variation was in SBR of the ONH, and the more exacerbated visual field impairment was (r=0.59, P=0.04).
  
  
  CONCLUSIONS
  These findings suggest that diurnal variations in the microcirculation of the ONH may play a role in the progression of NTG.
authors.affiliation: Department of Ophthalmology, Osaka Medical College, Takatsuki, Osaka, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Okuno
authors.forename: T
authors.initials: T
authors.lastname: Sugiyama
authors.forename: S
authors.initials: S
authors.lastname: Kojima
authors.forename: M
authors.initials: M
authors.lastname: Nakajima
authors.forename: T
authors.initials: T
authors.lastname: Ikeda
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D001794:Blood Pressure; D002940:Circadian Rhythm; D018450:Disease Progression; D005260:Female; D005901:Glaucoma / Q000503:physiopathology*; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D009898:Optic Disk / Q000098:blood supply*; D014794:Visual Fields