Superficial retinal blood flow density analysis and related factors in adolescents with different classification of high myopia / 中华眼底病杂志

Objective:To observe and analyze the superficial retinal blood flow density and its related influencing factors in the macular area of adolescents with different types of non-pathological high myopia (HM).Methods:A retrospective clinical study. From March to August 2022, 117 eyes of 117 adolescents who were admitted to Liaocheng Aier Eye Hospital due to myopia were included in the study. According to equivalent spherical degree (SE) and corneal curvature, subjects were divided into mild myopia or emmetropia group (control group), HM group, occult HM (OHM) group, and super HM (SHM) group, with 30 eyes, 28 eyes, 35 eyes, and 24 eyes, respectively. All subjects underwent medical optometry, intraocular pressure, optical coherence tomography (OCT), OCT angiography (OCTA), axial length (AL) and corneal curvature measurements. The diopter was SE. OCTA instrument was used to scan the macular region in the range of 6 mm×6 mm, and the software automatically divided it into three concentric circles centered on the fovea of the macular, namely, the central area with a diameter of 1 mm, the inner ring area with a diameter of 1-3 mm, and the outer ring area with a diameter of 3-6 mm. The superficial retinal vascular density (SRVD), vascular perfusion density (SBPD), the area, perimeter (PERIM), avascular index (AI) of foveal avascular area (FAZ) and retinal thickness were measured in the macular region as a whole and in different regions. One-way analysis of variance was used to compare the data among groups, and the least significant difference t-test was used to compare the data among groups. The correlation of AL, corneal curvature and intraocular pressure with SRVD and SBPD in macula was analyzed by Pearson correlation analysis. Results:There were significant differences in SRVD and SBPD in the central, inner and outer regions of macula in control group, HM group, OHM group and SHM group ( P<0.05). There were statistically significant differences in the thickness of the retina above, below and on the temporal side of the central and outer ring regions ( P<0.05). However, no statistically significant difference was in the thickness of the retina on the nasal side ( P>0.05). There was no significant difference in PERIM ( P>0.05). There were significant differences in FAZ area and AI ( P<0.05). Correlation analysis showed that AL was negatively correlated with SRVD and SBPD in macular whole and central, inner and outer ring regions ( P <0.05). Corneal curvature and SE were positively correlated with the SRVD and SBPD of macular whole, central area and outer ring area ( P<0.05). AL was negatively correlated with retinal thickness in the outer ring region ( P<0.05). SE was positively correlated with the thickness of the retina above, below and temporally in the outer ring region ( P<0.05). AL was negatively correlated with FAZ area and AI ( P<0.05). SE was positively correlated with FAZ area and PERIM ( P<0.05). Retinal thickness was positively correlated with SRVD and SBPD ( P<0.05). Conclusions:The SRVD and SBPD of different types of HM in adolescents decreases to different degrees. The thickness of the retina in the central region is thicker, and the retina in the outer ring region is thinner. With the decrease of SRVD, the retinal thickness gradually is thinner.

Application of retinal functional imager in retinal diseases / 眼科新进展

Newer retinal imaging technologies help us in understanding the pathogenesis of many retinal pathologies,such as diabetic retinopathy,age related macular degeneration,glaucoma and uveitis.Early detection of these retinal diseases can prevent the onset of progressive vision loss,and aid in the development of new treatment options.Retinal functional imager (RFI) is an unique and noninvasive functional imaging system.Unlike most of the available newer retinal imaging tools,the RFI not only shows retinal structural changes,but can directly monitor functional changes and measure hemodynamic parameters,such as retinal bloodflow velocity,oximetric state,etc.This article reviews the utility progress of RFI in various retinal diseases.

Effect of Pirenzepine Injected Intravitreously on Retinal Blood Flow in Cats / 上海第二医科大学学报

0.05). In the group of pirenzepine, the RBF, velocity and volume significantly increased at 0.5 h and 1 h after injection compared with that before injection (P0.05). Conclusion These results suggest that pirenzepine could increase RBF and oxygen in blood with the peak time at 0.5 h and 1 h after intravitreous injection.

Retinal Blood Flow Measurement in Patients with Unilateral Internal Carotid Artery Obstruction

PURPOSE: To evaluate the autoregulation of retinal blood flow, in patients with unilateral carotid artery obstruction. METHODS: In patients with unilateral carotid artery obstruction confirmed by carotid Doppler, magnetic resonance angiography, or transfemoral carotid angiography, retinal blood flow in both eyes was measured using Heidelberg retina flowmeter (HRF), and compared. Patients with other ocular disease such as ocular ischemic syndrome were excluded. RESULTS: There is no statistically significant difference in total mean blood flow of retina between each eyes of 5 patients with unilateral carotid artery obstruction (0.1) CONCLUSIONS: It was demonstrated that retinal blood flow autoregulation was maintained in case of chronically decreased blood flow such as internal carotid artery obstruction.

Effect of the Superior Cervical Sympathectomy on Experimental Retinal Branch Vein Occlusion in Rabbits

PURPOSE: Superior cervical sympathectomy was performed on argon laser induced experimental branched retinal vein occlusion in rabbits to evaluate its effect on retinal blood flow. METHODS: Branched retinal vein occlusion (BRVO) was induced by argon laser in 30 eyes (15 pigmented rabbits) divided into three groups. One and 3 weeks after inducing BRVO, superior cervical sympathectomy was performed in Group 1 (early) and 2 (late), respectively. Group 3 was left as a control group. Fundus photography, fluorescien angiography and Heidelberg Retinal Flowmetry (HRF) were performed prior to and after sympathectomy. Pathologic examination was done after enucleation. RESULTS: The sympathectomy groups, especially Group 1 (early), showed better recovery of retinal blood flow, volume, and velocity. CONCLUSIONS: Sympathetic block appears to produce dilatation of the retinal blood system, and we suggest stellate ganglion block technique as an effective treatment modality on human beings with BRVO.

The Effect of Superficial Temporal Artery Compression on Intraocular Microcirculation

To increase retinal blood flow, we attempted to increase blood flow of ophthalmic artery which in the major vascular supply to the eyeball. The authors evaluated changes in blood flow of ophthalmic artery and retinal capillary after compression of superficial temporal artery. In 5 normal healthy subjects, the superficial temporal artery was compressed for 10seconds and the blood flow was measured with color doppler imaging and Heidelberg Retinal Flowmeter(HRF). After compression, the mean volume of ophthalmic artery was increased by 59.3% and the mean change of diastolic velocity was significantly increased by 29.6%. Systolic velocity did not changing significantly. For evaluation of retinal microcirculation, we measured volume, flow, velocity in retina and optic nerve head. The relative ratio in changes of volume, flow, velocity were 87.9%, 91.5%, 92.6%, in retina respectively and 110.1%, 140.7%, 139.5%, respectively in optic nerve head. These significant changes were not statistically(P>0.05). In 5 diabetic patients with damaged autoregulatory mechanism, the relative ratio in changes of volume, flow, velocity were 114.25%, 118.30%, 117.6%, respectively. These changes were not statistically significant(P>0.05). Our results indicate that the increase of blood flow in ophthalmic artery by compressing superficial temporal artery did not increase retinal blood flow.

A Study on Measurements of Retinal Blood Flow Using a Fluorescent Leukocyte Angiography

This study was performed to develop a new method, fluorecent leukocyte angiography(FLAG), to measure retinal circulation. Fluorescein-stained leukocytes can be seen in all the retinal vessels during fluorescein angiography using Scanning Laser Ophthalmoscope(SLO FAG) and retinal blood flow can be measured by using leukocyte velocities in the retinal vessels. Methods were followings. Firstly, blood was withdrawn from vein, mixed with fluorescein(10%) and anticoagulant and then centrifuged. The yellowbrown coat layer containing fluorescin-stained leukocytes was selected and injected into the vein while performing SLO FAG. The image of FLAG displayed circulating hyperfluorescent leukocytes clearly in all retinal vessels, and allowed the measurement of leukocyte velocities. In conclusion, FLAG is a new method to measure blood flow in all the retinal vessels simultaneously and can be a useful tool for studying animal and human retinal circulation.