Additional Test: Diurnal IOPs
This patient had all IOP measurements taken in the afternoon. IOP is known to fluctuate throughout the day with the lowest in the morning and highest at night time when sleeping. The increase in IOP at night is particularly important for ocular perfusion pressure (OPP). Ocular perfusion pressure describes the blood flow to the optic nerve. OPP is described as the blood pressure minus the IOP. As IOP increases at night time, blood pressure decreases causing a decreased OPP. In patients who are taking medications for hypertension, taking medications at night time further decreases the blood pressure and OPP.
The patient’s next scheduled exam was in the morning to get a better understanding of the IOP fluctuation. Newer technologies are able to measure IOP throughout the day without the patient coming into the clinic, including the at home iCare.
Graph showing the daily fluctuation of IOP in glaucomatous and healthy eyes. The IOP
increased and was highest at night time when sleeping and lowest in the morning.19