Changes in Choroidal Circulation Hemodynamics Measured Using Laser Speckle Flowgraphy after a Cold Pressor Test in Young Healthy Participants.

Using laser speckle flowgraphy (LSFG), we investigated the time course of changes in choroidal circulation hemodynamics after a cold pressor test in healthy eyes. This prospective study included the right eye of 19 young healthy participants. The macular mean blur rate (MBR) was measured with LSFG. The MBR, intraocular pressure (IOP), systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), mean blood pressure (MBP), and ocular perfusion pressure (OPP) were evaluated at baseline; immediately after the test and 10, 20, and 30 min later. Immediately after the test (0 min), SBP, DBP, MBP, and OPP were significantly elevated compared with those at baseline. The macular MBR significantly increased by +10.3 ± 7.1% immediately after the test. However, there was no change after 10, 20, and 30 min in the above parameter. A significant positive correlation of the macular MBR with the SBP, MBP, and OPP was observed. In young healthy individuals, increased sympathetic activity induced by a cold pressor test increases choroidal hemodynamics in the macula along with an increase in systemic circulatory dynamics, which normalizes after 10 min. Therefore, LSFG may provide a novel approach for assessing sympathetic activity and intrinsic vascular responsiveness in the eye.