Comparison of Optic Nerve Head Blood Flow Autoregulation among Quadrants Induced by Decreased Ocular Perfusion Pressure during Vitrectomy

Abstract

Purpose The present study aimed to examine changes in optic nerve head (ONH) blood flow autoregulation in 4 quadrants (superior, nasal, inferior, and temporal) with decreased ocular perfusion pressure (OPP) during vitrectomy in order to determine whether there is a significant difference of autoregulatory capacity in response to OPP decrease at each ONH quadrant. Methods This study included 24 eyes with an epiretinal membrane or macular hole that underwent vitrectomy at Toho University Sakura Medical Center. Following vitrectomy, the tissue mean blur rate (MBR), which reflects ONH blood flow, was measured. Mean tissue MBRs in the four quadrants were generated automatically in the software analysis report. Measurements were conducted before and 5 and 10 min after intraocular pressure (IOP) elevation of approximately 15 mmHg in the subjects without systemic disorders. Results The baseline tissue MBR of the temporal quadrant was significantly lower than that of the other 3 quadrants (all P < 0.05). However, the time courses of tissue MBR in response to OPP decrease were not significantly different among the four quadrants during vitrectomy (P = 0.23). Conclusions There is no significant difference in the autoregulatory capacity of the four ONH quadrants in patients without systemic disorders during vitrectomy.

Silicon Photomultiplier Current and Prospective Applications in Biological and Radiological Photonics

“…A phenomenon supporting our expectation that SiPM will excel in biosensing applications is laser speckle [58]. Laser speckle contrast imaging (LASCA) is a very useful medical imaging technique [59][60][61][62] utilizing a coherent light source to irradiate a sample, usually some biological tissue. Light interactions will result in backscattered radiation, which can be imaged on a screen in order to detect variations of interference patterns over time due to movements in the object.…”

Colorimetric Analyses of the Optic Nerve Head and Retina Indicate Increased Blood Flow After Vitrectomy

“…Indeed, intraoperative manipulations, such as increased IOP, were shown to reduce retinal perfusion. 39 , 40 Thus, the observed improvement in blood flow after vitrectomy may bring a new perspective to explain the impact of vitrectomy and PH peeling in diabetic macular edema cases that remained unresponsive to anti-VEGF treatment 41 or in retinal vein occlusion. 42 …”