title: Enhanced pressure in the central retinal vein decreases the perfusion pressure in the prelaminar region of the optic nerve head.
abstract: OBJECTIVE
  The pressure in the central retinal vein (CRVP) has been shown to be higher in glaucoma patients than in controls. Until now, these measurements have been performed in arbitrary units or in units of ophthalmodynamometric force. In our study, a contact lens dynamometer, calibrated in mm Hg, was used to calculate the retinal perfusion pressure.
  
  
  METHODS
  A total of 27 patients with primary open angle glaucoma (POAG) and 27 healthy control subjects were included in the study. The IOP measurement included Goldmann applanation tonometry, whereas the pressure enhancement measurement consisted of contact lens dynamometry. results: the pressures are given in mm hg, and are expressed as the mean ± SD for the control subjects versus the POAG patients: IOP 14.4 ± 2.7 vs. 15.4 ± 2.9, systolic blood pressure 141 ± 20.1 vs. 153 ± 16.5 (P = 0.013), central retinal vein threshold pressure (CRVTP) 11.9 ± 3.8 vs. 16.8 ± 5.0, CRVP 15.0 ± 2.7 vs. 17.9 ± 4.2, and retinal perfusion pressure (PPret) standard 84 ± 12.2 vs. 94 ± 9.1 and new 83 ± 12.2 vs. 91 ± 9.6. The differences in PPret between using the new versus the standard method are 0.55 ± 1.33 vs. -2.5 ± 3.89 (P = 0.041 and P = 0.002, respectively). The PPret was at least 5.0 mm Hg lower in 5 of the 27 POAG patients when the new calculation method was used.
  
  
  CONCLUSIONS
  The perfusion pressure in the retina and prelaminar region of the optic nerve head (ONH) may be lower than expected because the CRVP may be higher. The pressure measurement in the central retinal vein may be a step toward a better understanding of ONH pathophysiology.
authors.affiliation: University Hospital Carl Gustav Carus Dresden, Technical University Dresden, Dresden, Germany. stodtmeister@t-online.de
authors.forename: Richard
authors.initials: R
authors.lastname: Stodtmeister
authors.forename: Sylvana
authors.initials: S
authors.lastname: Ventzke
authors.forename: Eberhard
authors.initials: E
authors.lastname: Spoerl
authors.forename: Andreas G
authors.initials: AG
authors.lastname: Boehm
authors.forename: Naim
authors.initials: N
authors.lastname: Terai
authors.forename: Michael
authors.initials: M
authors.lastname: Haustein
authors.forename: Lutz E
authors.initials: LE
authors.lastname: Pillunat
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure / Q000502:physiology*; D005260:Female; D005902:Glaucoma, Open-Angle / Q000503:physiopathology*; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009898:Optic Disk / Q000098:blood supply / Q000502:physiology*; D012169:Retinal Vein / Q000502:physiology*
keywords: central retinal vein; glaucoma; ophthalmodynamometry; optic nerve head; perfusion pressure