Choroidal expansion during the water drinking test.
OBJECTIVE
To evaluate the correlation between intraocular pressure (IOP) rise, ocular pulse amplitude (OPA), and choroidal thickness (ChT) during the water drinking test (WDT).


METHODS
Primary open-angle glaucoma (POAG) patients were submitted to the WDT followed by serial IOP measurements using dynamic contour tonometry (DCT), Goldman tonometry (GAT), and ChT measurements using ultrasonographic A and B-scan (USG). A control group not submitted to the test was also evaluated using DCT, GAT, and USG. Intraclass correlation coefficient (ICC) was calculated in the control group in order to assess the reproducibility of measurements. Spearman's coefficient (rho) was used to assess the correlation between the variables.


RESULTS
Thirty eyes were included in the study. There was a significant IOP rise during the WDT using both GAT and DCT (p < 0.001). The OPA and ChT measurements also increased significantly (p < 0.001). Spearman's correlation between the OPA values and ChT measurements was significant and moderate (rho = 0.40, p = 0.005). The average increase of OPA and ChT measurements occurred 15 min before the IOP rise.


CONCLUSIONS
There was a significant increase of OPA and ChT measurements followed by an IOP rise during the WDT. Increased choroidal volume due to hemodynamic forces may be enrolled in the mechanism of IOP elevation during this stress test.
De Moraes
Carlos Gustavo Vasconcelos
CG
Glaucoma Service, Department of Ophthalmology, University of Sao Paulo School of Medicine, Sao Paulo, SP, Brazil. gustavousp@gmail.com
Reis
Alexandre Soares Castro
AS
Cavalcante
Adhele Furlani de Sá
AF
Sano
Milena Eimi
ME
Susanna
Remo
R
D001794:Blood Pressure; D002829:Choroid / Q000000981:diagnostic imaging / Q000503:physiopathology*; D003941:Diagnostic Techniques, Ophthalmological; D004326:Drinking; D005260:Female; D005902:Glaucoma, Open-Angle / Q000503:physiopathology*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009798:Ocular Hypertension / Q000503:physiopathology; D014065:Tonometry, Ocular; D014463:Ultrasonography; D014867:Water
D014867:Water