title: Ocular rigidity, outflow facility, ocular pulse amplitude, and pulsatile ocular blood flow in open-angle glaucoma: a manometric study.
abstract: OBJECTIVE
  To compare ocular rigidity (OR) and outflow facility (C) coefficients in medically treated open-angle glaucoma (OAG) patients and controls, and to investigate differences in ocular pulse amplitude (OPA) and pulsatile ocular blood flow (POBF) between the two groups.
  
  
  METHODS
  Twenty-one OAG patients and 21 controls undergoing cataract surgery were enrolled. Patients with early or moderate primary or pseudoexfoliative OAG participated in the glaucoma group. A computer-controlled system, consisting of a pressure transducer and a microstepping device was employed intraoperatively. After cannulation of the anterior chamber, IOP was increased by infusing the eye with microvolumes of saline solution. IOP was recorded after each infusion step. At an IOP of 40 mm Hg, an IOP decay curve was recorded for 4 minutes. OR coefficients, C, OPA, and POBF were estimated from IOP and volume recordings.
  
  
  RESULTS
  There were no differences in age or axial length in the two groups. The OR coefficient was 0.0220 ± 0.0053 μl(-1) in the OAG and 0.0222 ± 0.0039 μl(-1) in the control group (P = 0.868). C was 0.092 ± 0.082 μL/min/mm Hg in the glaucoma group compared with 0.149 ± 0.085 μL/min/mm Hg in the control group at an IOP of 35 mm Hg (P < 0.001) and 0.178 ± 0.133 μL/min/mm Hg vs. 0.292 ± 0.166 μL/min/mm Hg, respectively, at an IOP of 25 mm Hg (P < 0.001). There were no differences in OPA or POBF between the two groups in baseline and increased levels of IOP (P > 0.05).
  
  
  CONCLUSIONS
  Manometric data reveal lower C in OAG patients and increased C with increasing IOP. There were no differences in the OR coefficient, OPA, and POBF between medically treated OAG patients and controls, failing to provide evidence of altered scleral distensibility and choroidal blood flow in OAG.
authors.affiliation: Ophthalmology Department, University Hospital of Larissa, Larissa, Greece. anna.dastiridou@gmail.com
authors.forename: Anna I
authors.initials: AI
authors.lastname: Dastiridou
authors.forename: Evangelia E
authors.initials: EE
authors.lastname: Tsironi
authors.forename: Miltiadis K
authors.initials: MK
authors.lastname: Tsilimbaris
authors.forename: Harilaos
authors.initials: H
authors.lastname: Ginis
authors.forename: Nikos
authors.initials: N
authors.lastname: Karyotakis
authors.forename: Pierros
authors.initials: P
authors.lastname: Cholevas
authors.forename: Sofia
authors.initials: S
authors.lastname: Androudi
authors.forename: Ioannis G
authors.initials: IG
authors.lastname: Pallikaris
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure / Q000502:physiology*; D004547:Elastic Tissue / Q000502:physiology*; D005260:Female; D005902:Glaucoma, Open-Angle / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D008365:Manometry; D008875:Middle Aged; D011673:Pulsatile Flow / Q000502:physiology; D012039:Regional Blood Flow / Q000502:physiology
keywords: aqueous outflow; biomechanics; blood flow; glaucoma