Characterization of laser speckle flowgraphy pulse waveform parameters for the evaluation of the optic nerve head and retinal circulation

To characterize laser speckle flowgraphy (LSFG) pulse waveform parameters for ocular circulation evaluation, a multicenter, prospective, cross-sectional study was conducted in 111 eyes of 86 healthy Japanese individuals. Optic nerve head (ONH) tissue-area, vessel-area mean blur rate (MT and MV, respectively), and MT and MV pulse waveform parameters were obtained using LSFG and ONH structural parameters using planimetry. Multivariate linear mixed-effects modeled regression analysis identified factors contributing to MT- or MV-waveforms using age, gender, smoking history, body mass index, systolic and diastolic blood pressure, heart rate, intraocular pressure, axial length, disc, rim, and β-peripapillary atrophy areas, MT or MV, central retinal artery, and vein equivalents (CRAE and CRVE) as explanatory variables. MT- and MV-waveforms significantly correlated with one or more systemic factors, consistent with previous studies. Following confounding factor adjustment, MT-Skew significantly negatively correlated with β-PPA area (P = 0.026); MT- and MV-flow acceleration index positively correlated with CRAE, MT, and MV (P = 0.041–< 0.001), compatible with these parameters’ observed correlations to systemic factors. Significantly negative correlations of the blowout score and acceleration time index to CRAE partly conflicted with their correlations to systemic factors, and other waveform parameters showed little correlation to ocular factors. Thus, Skew and flow acceleration index assisted the in vivo ocular circulation characterization.

Endocannabinoid System and Ocular Vascularization

The focus of this review is the role of endocannabinoid system in ocular and systemic circulation. By critically examining preclinical and clinical research, we explore the cannabinoid receptors localization and vascular implications as well as their interaction with other anti-inflammatory drugs. The objective is to transfer knowledge on the use of cannabinoids, specifically their effect on ocular circulation and intraocular pressure, and provide a better understanding of the endocannabinoid system complexity in modulating local and systemic circulations in order to identify potential uses and limitations of cannabinoid-based therapeutics.

A Change in Ocular Circulation after Photocoagulation for Retinopathy of Prematurity in a Neonate

Background: The dilation of veins and tortuosity of arteries that occur in retinopathy of prematurity (ROP) are improved by therapy, and thus posttherapy changes in ocular circulation are also conceivable. We report a case of ROP in which we were able to measure the ocular circulation before and after photocoagulation therapy, using a laser speckle flowgraphy (LSFG) system that is modified for neonates. Case Report: A female infant was born at 25 weeks’ gestation with a birth weight of 808 g. We performed photocoagulation in both eyes at age 15 weeks, and we measured the ocular circulation with the “LSFG-baby” system before and at 12 weeks after the photocoagulation treatment. We also measured the mean blur rate (MBR) in the optic nerve head (ONH) and the relative flow volume (RFV) in the retinal vessels, and we examined the change rates from before to after treatment. The changing rate of the MBR-A (the mean of all values) in the ONH in the right and left eyes was 76.5 and 98.5%, respectively. The vascular RFV in the severe dilation and tortuosity quadrant also tended to decrease. Conclusions: Photocoagulation improved the dilation of veins and tortuosity of arteries and reduced the ocular blood flow in this neonate with ROP. The LSFG-baby system effectively and directly revealed the optic nerve and retinal blood vessels.

Abstract TP126: Ocular Circulation in Carotid Artery Stenosis Treated by CEA or CAS

Background: The authors evaluated the effect of carotid artery revascularization surgery for ocular circulation and chronic ocular ischemic syndrome (OIS). Methods: The authors examined ninety-3 patients with carotid artery stenosis (more than 50% stenosis) at its origin treated by carotid endarterectomy (N=58) or carotid artery stenting (N=34). Twenty-six patients (28%) complained of chronic OIS evaluated by the ophthalmic examination. Ocular circulation was examined before and after revascularization surgery using ophthalmic artery (OphAr) and central retinal artery (CRA) color Doppler flow imaging. Results: 1) Ocular circulation: Preoperatively, the average OphAr peak systolic flow velocity (Vs) was 0.05 m/sec, and the average CRA Vs was 0.07 m/sec. At 1 week after surgery, the average OphAr Vs significantly increased to 0.32 ( p < 0.05), and the average CRA Vs significantly increased to 0.11 m/sec ( p < 0.05). These significant improvements were sustained throughout the three months of the follow up.2) OIS: During the follow-up period (mean: 3.6 years), 16 patients (62%) showed visual acuity improvement, and no patients complained of amaurosis fugax or worsening of the chronic OIS. Conclusion: Carotid revascularization surgery was effective in improving the ocular circulation, and it was also useful for the chronic OIS due to the carotid artery stenosis.