Study finds, Changes in pulse waveforms in response to Intra
The influences of intraocular pressure (IOP) elevations on the pulse waveform in the optic nerve head (ONH) were evaluated using laser speckle flowgraphy (LSFG) in normal subjects.

An ophthalmodynamometer was pressed on the sclera to increase the IOP by 20mmHg or 30mmHg for 1min and by 30mmHg for 10min. The mean blur rate (MBR) and the 8 pulse waveform parameters determined using LSFG were measured before, immediately after and during an IOP elevation, and after the IOP returned to the baseline pressure.

--A significant elevation in the IOP and a significant reduction in the ocular perfusion pressure (OPP) were found after applying the ophthalmodynamometer.

--The blowout score (BOS) reduced significantly, and the flow acceleration index and resistivity index increased significantly immediately after increasing the IOP by 20 or 30mmHg.

--The BOS reduced significantly, and the FAI and RI increased significantly after the IOP elevation by 30mmHg in both experiment 2 and 1.

--However, the BOS and RI recovered significantly at time 10 compared to that in time 0 (immediately after IOP elevation) during the 10-min IOP elevation.

In conclusion, the BOS, FAI, and RI of the pulse waveforms changed significantly with an acute elevation in the IOP. The change should be related to the larger difference between the maximum and minimum MBRs during the IOP elevation.