Measurement of the blood pressure in the vessels of the retina of the eye. A small instrument is pressed against the eye until the vessels are seen (through an ophthalmoscope) to collapse. The pressure recorded by the instrument reflects the pressure within the vessels of the retina. In certain disorders of the blood circulation to the eye, the pressure in the vessels is reduced and the vessels can be made to collapse by a pressure that is lower than normal.
Determination of pressure in the ophthalmic artery by use of an instrument that produces pressure on the eyeball until pulsations in the ophthalmic artery are seen through the ophthalmoscope, indicating the diastolic pressure. As the pressure is increased, the vessel collapses and the systolic pressure is obtained.