UNASSIGNED: Both hypertension and diabetes are known to increase the wall-to-lumen ratio (WLR) of retinal arterioles, but the differential effects are unknown. Here, we study the timing and relative impact of hypertension versus diabetes on the WLR in diabetic retinopathy (DR) to address this unresolved question.
UNASSIGNED: This prospective cross-sectional study compared the retinal arteriolar WLR in 17 healthy eyes, 15 with diabetes but no apparent DR (DM no DR), and 8 with diabetic macular edema (DME) and either nonproliferative or proliferative DR. We imaged each arteriole using adaptive optics scanning laser ophthalmoscopy and measured the WLR using ImageJ. Multiple linear regression (MLR) was performed to estimate the effects of hypertension, diabetes, and age on the WLR.
UNASSIGNED: Both subjects with DM no DR and subjects with DME had significantly higher WLR than healthy subjects (0.36 ± 0.08 and 0.42 ± 0.08 vs. 0.29 ± 0.07, 1-way ANOVA P = 0.0009). MLR in healthy subjects and subjects with DM no DR showed hypertension had the strongest effect (regression coefficient = 0.08, P = 0.009), whereas age and diabetes were not significantly correlated with WLR. MLR in all three groups together (healthy, DM no DR, and DME) showed diabetes had the strongest effect (regression coefficient = 0.05, P = 0.02), whereas age and hypertension were not significantly correlated with WLR.
UNASSIGNED: Hypertension may be an early driver of retinal arteriolar wall thickening in preclinical DR, independent of age or diabetes, whereas changes specific to DR may drive wall thickening in DME and later DR stages.
UNASSIGNED: We offer a framework for understanding the relative contributions of hypertension and diabetes on the vascular wall, and emphasize the importance of hypertension control early in diabetes even before DR onset.

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Central retinal artery occlusion (CRAO), like a stroke in the brain, is a critical eye condition that requiring urgent medical attention. Patients with CRAO present with acute loss of vision and the visual prognosis is poor with low chance of spontaneous visual recovery. Moreover, the risk of developing ischaemic heart disease and cerebral stroke is increased due to the presence of underlying atherosclerotic risk factors. Currently, there is no officially recommended treatment for CRAO. This review will describe the anatomy, pathophysiology, clinical features of CRAO, as well as exploring existing and potential future approaches for managing the condition.
摘要: 视网膜中央动脉阻塞 (CRAO) 与脑卒中一样, 是一种需要紧急救治的重要眼病。CRAO患者表现为急性视力丧失, 视力预后较差, 自发视力恢复的机率较低。此外, 由于潜在动脉粥样硬化危险因素的存在, 增加了患缺血性心脏病和脑卒中的风险。目前, 还没有官方推荐的CRAO治疗方法。这篇综述将描述CRAO的解剖、病理生理学、临床特征, 并探索现有和潜在的未来治疗方法。.

OBJECTIVE: A third of asymptomatic individuals with type 1 diabetes (T1D) show signs of cerebrovascular disease in brain MRI. These signs associate with advanced stages of diabetic retinal disease, but not in mild or moderate retinopathy. We aimed to evaluate a wider spectrum of retinal changes by exploring the relationship between quantitative measures of retinal vessel parameters (RVP) and cerebrovascular changes in T1D.
METHODS: We included 146 neurologically asymptomatic individuals with T1D [51% women, median age 40 (33.0-45.1) years] and 24 healthy, sex-matched and age-matched controls. All individuals underwent a clinical and biochemical work-up and brain MRI, which was evaluated for cerebral microbleeds (CMBs), white matter hyperintensities, and lacunar infarcts. RVPs, including central retinal arteriole (CRAE) and central retinal vein (CRVE) equivalents and the ratio of the two variables (arteriovenous ratio, AVR) were assessed quantitatively by a computer-assisted method (IVAN software, version 3.2.6) from fundus images.
RESULTS: Among T1D participants, those with CMBs had a lower arteriovenous ratio (AVR) compared with those without CMBs ( P  = 0.023). AVR was inversely associated with the amount of CMBs ( r  = -0.063, P  = 0.035). CMB prevalence was higher in those with AVR below the median (31%) compared with above the median (16%, P  < 0.001), and this difference was significant also after individuals with only no-to-mild retinopathy were included (28 vs. 16%, P  = 0.005). A correlation between blood pressure and CRAE ( r  = -0.19, P  = 0.025) appeared among those with T1D.
CONCLUSIONS: Regardless of the severity of diabetic retinopathy, AVR is associated with the existence of CMBs in T1D.

BACKGROUND: To evaluate the changes in retrobulbar circulation after strabismus surgery and to assess the relationship of these changes with choroidal thickness (CT).
METHODS: This prospective study included 26 eyes of 26 patients who underwent strabismus surgery and 15 eyes of 15 healthy individuals as control group. The patients who had single horizontal muscle surgery were included in Group 1 (n = 14); and those who had surgery on both horizontal muscles were included in Group 2 (n = 12). Peak systolic velocity (PSV), end-diastolic velocity (EDV), resistive index (RI) and pulsatility index (PI) of ophthalmic artery (OA), posterior ciliary artery (PCA), and central retinal artery (CRA) were measured using Color Doppler Ultrasonography. Subfoveal CT was measured via Optical Coherence Tomography. All measurements were obtained preoperatively, at 1st week and 1st month after surgery.
RESULTS: There were no differences regarding preoperative blood flow velocity parameters among the groups. OA RI increased significantly at 1st week and 1st month after surgery in Group 1 and 2 (P = 0.029 and P = 0.045, respectively). There was a significant increase in PCA PSV at 1st week in Group 1 (P = 0.002). There was no difference between the mean preoperative and postoperative CT among the 3 groups. A negative correlation between the percentage changes of CT and CRA EDV was found in Group 2 (P = 0.011).
CONCLUSIONS: Single and double horizontal rectus muscle surgery have a measurable effect on retrobulbar hemodynamics but these changes do not correlate with CT.

Retinal vessel calibers share anatomic and physiologic characteristics with the cerebral vasculature and can be visualized noninvasively. In light of the known microvascular contributions to brain health and cognitive function, we aimed to determine if, in a community based-study, retinal vessel calibers and change in caliber over 8 years are associated with cognitive function or trajectory. Participants in the Multi-Ethnic Study of Atherosclerosis (MESA) cohort who completed cognitive testing at Exam 5 (2010-2012) and had retinal vascular caliber measurements (Central Retinal Artery and Vein Equivalents; CRAE and CRVE) at Exam 2 (2002-2004) and Exam 5 were included. Using multivariable linear regression, we evaluated the association of CRAE and CRVE from Exam 2 and Exam 5 and their change between the two exams with scores on tests of global cognitive function (Cognitive Abilities Screening Instrument; CASI), processing speed (Digit Symbol Coding; DSC) and working memory (Digit Span; DS) at Exam 5 and with subsequent change in cognitive scores between Exam 5 and Exam 6 (2016-2018).The main effects are reported as the difference in cognitive test score per SD increment in retinal vascular caliber with 95% confidence intervals (CI). A total of 4334 participants (aged 61.6 ± 9.2 years; 53% female; 41% White) completed cognitive testing and at least one retinal assessment. On multivariable analysis, a 1 SD larger CRAE at exam 5 was associated with a lower concomitant CASI score (- 0.24, 95% CI - 0.46, - 0.02). A 1 SD larger CRVE at exam 2 was associated with a lower subsequent CASI score (- 0.23, 95%CI - 0.45, - 0.01). A 1 SD larger CRVE at exam 2 or 5 was associated with a lower DSC score [(- 0.56, 95% CI - 1.02, - 0.09) and - 0.55 (95% CI - 1.03, - 0.07) respectively]. The magnitude of the associations was relatively small (2.8-3.1% of SD). No significant associations were found between retinal vessel calibers at Exam 2 and 5 with the subsequent score trajectory of cognitive tests performance over an average of 6 years. Wider retinal venular caliber was associated with concomitant and future measures of slower processing speed but not with later cognitive trajectory. Future studies should evaluate the utility of these measures in risk stratification models from a clinical perspective as well as for screening on a population level.

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OBJECTIVE: To investigate the impacts of angiotensin II (Ang II) on retinal artery changes in apolipoprotein E deficient (apoE-/-) mice.
METHODS: apoE-/- male mice were infused by minipumps with Ang II at 1000 ng/kg·min (Ang II group) or saline (control group) for 28d. They were underwent ophthalmic fundus examination on day 0, 14, and 28 of infusion. Histopathologic examination, ribonucleic acid (RNA) sequencing and local Ang II measurement of retinas were conducted.
RESULTS: Ophthalmic fundus examination showed Ang II infusion promoted the formation of retinal arterial aneurysm-like lesions on day 28. Optical coherence tomography revealed the ganglion cell and inner plexiform layer (GCIPL) thickness in the control group was significantly thinner than that in Ang II group (P<0.001). Hematoxylin-eosin staining demonstrated diffused swelling of GCIPL layer and its disordered structure in Ang II group. Transmission electron microscopy showed Ang II infusion caused aggravation of atherosclerotic lesions, including increased swelling, roughness, disorganization of the retinal vasculature, and vacuoles formation. RNA-sequencing and gene ontology enrichment analysis demonstrated that the structure and function of cellular membrane might be disturbed and visual function might be compromised by Ang II. The local level of Ang II was higher in Ang II infusion group but did not show significant differences compared to the control group (P=0.086).
CONCLUSIONS: Ang II infusion promotes the formation of retinal arterial aneurysm-like lesions in apoE-/- mice, causing aggravation of atherosclerotic lesions, more severe disorganization of the retinal vasculature and disturbance of the cellular membrane.

A major hurdle to therapeutic development in cerebral small vessel diseases is the lack of in-vivo method that can be used repeatedly for evaluating directly cerebral microvessels. We hypothesised that Adaptive Optics (AO), which allows resolution images up to 1-2 μm/pixel at retinal level, could provide a biomarker for monitoring vascular changes in CADASIL, a genetic form of such condition. In 98 patients and 35 healthy individuals, the wall to lumen ratio (WLR), outer and inner diameter, wall thickness and wall cross-sectional area were measured in a parapapillary and/or paramacular retinal artery. The ratio of vessel diameters before and after light flicker stimulations was also calculated to measure vasoreactivity (VR). Multivariate mixed-model analysis showed that WLR was increased and associated with a larger wall thickness and smaller internal diameter of retinal arteries in patients. The difference was maximal at the youngest age and gradually reduced with aging. Average VR in patients was less than half of that of controls since the youngest age. Any robust association was found with clinical or imaging manifestations of the disease. Thus, AO enables the detection of early functional or structural vascular alterations in CADASIL but with no obvious link to the clinical or imaging severity.