title: Correlation between water-drinking test outcomes and body mass index in primary open-angle glaucoma patients under clinical treatment.
abstract: OBJECTIVE
  The aim of this study was to evaluate the correlation between water-drinking test (WDT) outcomes and body mass index (BMI) in primary open-angle glaucoma (POAG) patients.
  
  
  METHODS
  This study enrolled 41 POAG patients (41 eyes) under glaucoma treatment. POAG was defined as any typical signs of glaucomatous optic neuropathy and/or visual-field finding, with open angle on gonioscopy. After inclusion, patients underwent weight and height measurements. The WDT was performed, consisting of a baseline intraocular pressure (IOP) measurement, followed by the ingestion of 1 L of tap water within 5 min. Then, IOP was measured four times, at 15-min intervals. IOP peak was considered the maximum value of the four measurements, and IOP fluctuation was defined as the difference between the peak and the baseline IOP.
  
  
  RESULTS
  The analysis of the IOP profile during the WDT revealed significant differences between groups with different BMIs. Patients with a higher BMI presented lower IOP peaks and fluctuation (P < 0.043; P < 0.001). There was also a significant correlation between the IOP fluctuation (both absolute [P < 0.024] and percentage [P < 0.021] values) and the following baseline parameters: BMI, weight, height, and cup-to-disc ratio.
  
  
  CONCLUSIONS
  These data suggest that patients' individual characteristics, including BMI and weight, may influence the results of the WDT. In addition, patients with a higher BMI presented lower IOP fluctuation in the WDT.
authors.affiliation: Department of Ophthalmology, Federal University of São Paulo, São Paulo, Brazil. vecastrolima@yahoo.com.br
authors.forename: Verônica C
authors.initials: VC
authors.lastname: Lima
authors.forename: Tiago S
authors.initials: TS
authors.lastname: Prata
authors.forename: Rodrigo A B
authors.initials: RA
authors.lastname: Lobo
authors.forename: Augusto
authors.initials: A
authors.lastname: Paranhos
mesh_terms: D000368:Aged; D000959:Antihypertensive Agents / Q000627:therapeutic use; D015992:Body Mass Index; D002940:Circadian Rhythm; D003941:Diagnostic Techniques, Ophthalmological; D004326:Drinking; D005260:Female; D005902:Glaucoma, Open-Angle / Q000175:diagnosis / Q000188:drug therapy / Q000503:physiopathology*; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects; D008297:Male; D014867:Water
chemical_list: D000959:Antihypertensive Agents; D014867:Water