title: Comparison between intraocular pressure spikes with water loading and postural change.
abstract: BACKGROUND
  To compare the agreement between peak intraocular pressures measured through the water drinking test and the supine test, in patients with primary open angle glaucoma.
  
  
  METHODS
  Consecutive, prospective, blinded.
  
  
  METHODS
  Twenty-one patients from the Glaucoma Unit, Prince of Wales Hospital, Sydney, Australia.
  
  
  METHODS
  For the supine test, intraocular pressure was recorded immediately after the patient had lain down and at 20 and 40 min. At the second evaluation, intraocular pressure was measured in each patient after drinking 10 mL/kg body weight of water for the water drinking test. Again, all patients had their intraocular pressure measured at 20 and 40 min (t = 20 and t = 40, respectively). Patients were excluded from the study if they had pre-existing cardiac, renal or pulmonary complications or had concurrent ocular disease or an anatomical abnormality (including angle recession, peripheral anterior synechiae and developmental anomalies of the angle) that may have influenced intraocular pressure.
  
  
  METHODS
  Bland-Altman analysis.
  
  
  RESULTS
  Bland-Altman analysis indicated an overall excellent agreement in terms of mean difference between methods (1.0, -1.0 and -0.90 mmHg, at 0, 20 and 40 min, respectively). Further, with the exception of t = 40, all measured time points had 95% confidence intervals within 6.5 mmHg of their mean difference on the Bland-Altman plot.
  
  
  CONCLUSIONS
  There was close agreement between the intraocular pressure values of the supine test and water drinking test. However, as the water drinking test may be uncomfortable and potentially hazardous, there is potential that the supine test may be a safer and more comfortable alternative.
authors.affiliation: The University of New South Wales, Kensington, New South Wales, Australia.|The Department of Ophthalmology, Prince of Wales Hospital, Randwick, New South Wales, Australia.
authors.forename: Calum Wk
authors.initials: CW
authors.lastname: Chong
authors.affiliation: The Department of Ophthalmology, Prince of Wales Hospital, Randwick, New South Wales, Australia.
authors.forename: Sarah B
authors.initials: SB
authors.lastname: Wang
authors.affiliation: The University of New South Wales, Kensington, New South Wales, Australia.
authors.forename: Neeranjali S
authors.initials: NS
authors.lastname: Jain
authors.affiliation: The University of Sydney, Camperdown, New South Wales, Australia.
authors.forename: Cassandra S
authors.initials: CS
authors.lastname: Bank
authors.affiliation: The University of New South Wales, Kensington, New South Wales, Australia.
authors.forename: Ravjit
authors.initials: R
authors.lastname: Singh
authors.affiliation: The University of New South Wales, Kensington, New South Wales, Australia.|The Department of Ophthalmology, Prince of Wales Hospital, Randwick, New South Wales, Australia.|Chatswood Grove Eye Clinic, Chatswood, New South Wales, Australia.
authors.forename: Allan
authors.initials: A
authors.lastname: Bank
authors.affiliation: The University of New South Wales, Kensington, New South Wales, Australia.|The Department of Ophthalmology, Prince of Wales Hospital, Randwick, New South Wales, Australia.|Chatswood Grove Eye Clinic, Chatswood, New South Wales, Australia.
authors.forename: Ian C
authors.initials: IC
authors.lastname: Francis
authors.affiliation: The Department of Ophthalmology, Prince of Wales Hospital, Randwick, New South Wales, Australia.
authors.forename: Ashish
authors.initials: A
authors.lastname: Agar
mesh_terms: D000368:Aged; D003941:Diagnostic Techniques, Ophthalmological; D004326:Drinking / Q000502:physiology*; D005260:Female; D005902:Glaucoma, Open-Angle / Q000175:diagnosis / Q000503:physiopathology*; D006068:Gonioscopy; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D011446:Prospective Studies; D013312:Stress, Physiological; D016683:Supine Position / Q000502:physiology*; D014065:Tonometry, Ocular; D014867:Water / Q000008:administration & dosage*
chemical_list: D014867:Water
keywords: glaucoma; intraocular pressure; postural change; supine test; water drinking test