Water-Drinking Test

In the normal eye the response of ocular pressure to water drinking exhibits marked individual variation. It is, in general, an increase in pressure reaching maximum in 30 minutes and recovering fully in 60 minutes. The magnitude of pressure change varies markedly with the time after water drinking at which it is measured. It also varies with repetition of testing and with age. The effect of these factors confuses the predictive usefullness of the test and must, therefore, be rigidly controlled in the clinical situation. The C values of tonography performed 30 minutes after water drinking did not differ significantly from that of tonography performed 60 minutes after water drinking.