Objective To evaluate the correlation of oxygen saturation of retinal vessels and diabetic retinopathy (DR) stages or HbA1c level in patients with DR. Methods Cross sectional study. A total of 102 patients (102 eyes) with DR and 20 age-matched healthy controls (20 eyes) (normal control group) were enrolled in this study. DR patients were divided into mild and moderate non-proliferative DR (NPDR) group (55 patients), severe NPDR group (26 patients) and proliferative DR (PDR) group (21 patients). DR patients were also divided into 3 groups according to the HbA1c level including HbA1c>9%(8 patients), HbA1c 7%–9%(33 patients) and HbA1c<7% group (61 patients). The oxygen saturation of retinal vessel was measured by spectrophotometric oximetry unit in the retinal vessels with a diameter greater than 60μm in the area around the optic disc. Results The retinal artery oxygen saturation of patients in severe NPDR group was significantly higher than that in mild to moderate NPDR group and normal control group (F=13.670, P<0.05). The retinal vein oxygen saturation of patients in PDR group was significantly higher than that in mild to moderate NPDR group and normal control group (F=6.379, P<0.05). The difference between retinal artery and vein oxygen saturation of patients in severe NPDR group was significantly bigger than that in mild to moderate NPDR group and PDR group (F=5.536, P<0.05). The retinal artery and vein oxygen saturation in patients of HbA1c>9%group were significantly higher than that in HbA1c 7%–9%group and HbA1c<7%group (F=9.989, 10.208;P<0.05). The differences between retinal artery and vein oxygen saturation were same between patients in HbA1c>9%, HbA1c 7%<9%and HbA1c<7%group (F=1.836, P>0.05). Conclusions The retinal artery and vein oxygen saturation in DR patients are related to the DR stages. Severe NPDR patients show the highest retinal artery oxygen saturation as well as biggest difference between retinal artery and vein oxygen saturation. There is also a trend that retinal vein oxygen saturation increases with higher DR stages. In addition, there is a positive correlation between the levels of HbA1c and retinal vessel oxygen saturation.

Objective To observe the characteristics of optical coherence tomography (OCT) angiography (OCTA) in retinal vein occlusion (RVO).Methods Prospective and observational study.Clinical examination of 81 consecutive patients (86 eyes) diagnosed with RVO were included in the study,in which the branch retinal vein occlusion in 47 eyes,central retinal vein occlusion in 39 eyes.Forty-five patients were male and 36 patients were female.Aged from 28 to 76 years old,the mean age was (55.36±10.01) years old.Comprehensive optical and imaging examination were performed,including fundus photography,fundus fluorescein angiography (FFA),spectral domain OCT,en face OCT and OCTA.The retinal blood flow imaging scan mode and the optic disc blood flow imaging scan mode were performed,the scanning region in the macular area were 3 mm × 3 mm,6 mm × 6 mm,8 mm × 8 mm respectively,around the optic disc were 3 mm × 3 mm and 4.5 mm × 4.5 mm.Each region scans 2 times.The characteristics of foveal avascular zone change,macular edema,non-perfusion and optical disc edema in OCTA and their corresponding FFA and en face OCT were observed.Results By OCTA,67 eyes (77.9％) for foveal avascular zone change,23 eyes (26.7％) for macular edema,40 eyes (46.5％) for non-perfusion,and 33 eyes (38.4％) for optical disc edema can be detected.The foveal avascular zone change can be indentified as the tranformation,destruction and even vanish of the arch in superfacial layer of retinal macular area,acompanied with the dilatation and thickening of capillary vessels,the occlusion and expanding of capillary vessels arounded the foveal avascular zone in the deep layer of macular area.Those performances were more clear than FFA.The main expression of macular edema was low signal and was not as clear as en face OCT.The tortuosity and expansion of retinal vessels,density decreasing and even occlusion or abnormal traffic branch of capillary vessels can be observed in non-perfusion.These observations were similar to FFA.However,pieces of highly signal identical with non-perfusion area can b.e detected in chroid capillary.The representation of optical disc edema was the brush-like expanding of capillary vessels aroud optical disc.Conclusions OCTA can help for observing the abnormal changing of capillary vessels in foveal avascular zone and macular edema,non-perfusion and optical disc edema.Foveal avascular zone change showed occlusion and expanding of capillary vessels around the foveal avascular zone in the deep layer of macular area.Macular edema showed the weak signal.Non-perfusion showed tortuosity and expansion of retinal vessels,density decreasing and even occlusion or abnormal traffic branch of capillary vessels.Optical disc edema showed brush-like expanding of capillary vessels around optical disc.

Objective To quantitatively analyze the changes ofchoroidal capillaries in chronic central serous chorioretinopathy (CCSC) before and after half-dose photodynamic therapy (PDT).Methods A retrospective cohort study.Nineteen patients (21 eyes) with CCSC were enrolled in this study from November 2017 to September 2018 in People's Hospital of Wuhan University.Among them,there were 14 males (15 eyes) and 5 females (6 eyes),with diseases course over than 6 months.All patients underwent half-dose PDT.Twenty normal subjects (40 eyes) matched with age and sex in CCSC group were taken as controls.The subfoveal choroidal thickness (SFCT) was measured by Heidelberg depth enhanced imaging-OCT before and after PDT treatment in CCSC patients and in normal subjects.Spectral-domain OCT (Retina map) and Angio-OCT angiography (3 mm × 3 mm) were arranged for all subjects at the same time.Macular fovea retinal thickness (CMT) was recorded under OCT-Retina map mode,and Angio-OCT 3 mm × 3 mm choroidal capillary images were binarized using Image J software,and calculating the area ratio of low pixel area as flow signal void (FSV).BCVA,spectral-domain OCT and Angio-OCT were performed 1 week and 1,3 months after PDT with the same equipment and methods before PDT.The changes of CMT,SFCT,FSV and BCVA in CCSC patients before and after PDT treatment were compared.Pearson correlation analysis was used to analyze the correlation between FSV and SFCT,age.Results The average CMT,SFCT and FSV in CCSC patients increased significantly compared with the controls (P＜0.05).The average SFCT and FSV in CCSC patients 3 months after treatment were higher and the average CMT decreased compared with the controls (P=0.000,0.000,0.000).Comparison before and after PDT in CCSC patients:there were significant differences in average CMT,SFCT and FSV before and after PDT (P=0.000,0.000,0.000).Post Hoc multiple comparisons showed that the average CMT (P=0.000,0.000,0.000,0.000,0.000) and FSV (P=0.010,0.000,0.000,0.001,0.000) decreased significantly in all time points except for 1 month and 3 months after treatment,so as the average FSV (P=0.788,0.702).The average SFCT decreased 1 month and 3 months after treatment compared with the baseline (P=0.024,0.008),and there was no significant difference between before treatment and 1 week after treatment (P=0.162),and between 1 month and 3 months after treatment (P=0.687).The correlation analysis showed that there was no correlation between FSV and age in CCSC patients (r=0.052,P=0.822),but there was a correlation between FSV and age in controls (r=0.716,P=0.000).Conclusion Quantitative analysis of OCTA showes the degree of choriocapillary ischemia in the form of FSV in CCSC patients decreased after PDT treatment,however,which is still higher than normal controls.

The separation of outer retinal photoreceptors in patients with toxoplasmosis chorioretinitis was first named bacillary layer detachment (BALAD), which was manifested as a split at the level of the photoreceptor inner segment myoid creating a distinctive intraretinal cavity in optical coherence tomography.Subsequently BALAD has been reported by many researchers in different diseases.In the outer retina, the myoid is a relatively weak structure in photoreceptor inner segment.When the outward force that promotes the attachment of the photoreceptor outer segment to the retinal pigment epithelium exceeds the tensile strength of the photoreceptor inner segment myoid, the myoid zone splits and BALAD occurs.BALAD has its unique multimodal imaging characteristics, and the identification of it can provide a new idea for the diagnosis, detection and treatment of ocular diseases.This paper reviewed the development of BALAD nomenclature, its anatomical structure, pathophysiological mechanism and multimodal image features.