Invited persons who agree to participate in the study will be scheduled for a screening visit at the eye clinic, during which they will learn more about the study. On the day of the screening visit, they will be provided with detailed information about the study, after which they will decide whether or not to participate. If they agree, they will sign the consent form. The screening visit will then be conducted by the research personnel and will take place at the eye clinic in a designated closed office and will include measurement of visual acuity, assessment of the anterior and posterior segments of the eye, measurement of IOP by Goldmann applanation tonometry. If after the screening exam it is determined that they do not qualify for the study, they will be told why they are being excluded. Healthy controls as well as glaucomatous patients not on treatment will be fitted with the BP and IOP monitoring devices. Those who are on glaucoma medication will be asked to stop their medication starting the day following the screening visit for the duration detailed in the inclusion criteria, and be given an appointment for the for IOP and BP measurement. On the appointment day, they will be fitted the BP and IOP monitoring devices. The BP monitor will be set up to take the measurements automatically every 30 min during the day and every hour at night until the next morning. The IOP monitor will take measurements every 10 minutes during the 24-hour period. Both devices are computerized and record all the measurements and reading times. Patients will be required to return to the clinic the next morning for removal of the devices, after which there will be no further visits.