Retinal and optic nerve ischemia

Chronic ocular small vessel disease: An overview of diabetic retinopathy and its relationship with cardiovascular health

Diabetic retinopathy (DR) is a potentially blinding disease originating from small vessel damage in the retina in chronic hyperglycemic states. DR has a complex multi-pathway driven pathogenesis resulting in diabetic macular edema and retinal ischemia, the former being the most common cause of vision impairment in DR. Hypoxia induced cytokines stimulate vascular endothelial growth factor (VEGF) production and subsequent angiogenesis with resultant mechanical retinal damage over time. Anti-VEGF therapy is effective for the treatment of center-involving diabetic macular edema. There is evolving evidence showing the effectiveness of anti-VEGF as both adjuvant and monotherapy in the treatment of proliferative DR, however laser photocoagulation continues to remain the standard of care. DR in large cohort studies has been shown to be an independent risk factor for the development of cardiovascular disease and mortality. In addition, changes in retinal vascular caliber ratios may have implications for risk of macrovascular events with a gender discrepancy towards women.

Cerebral magnetic resonance imaging of coincidental infarction and small vessel disease in retinal artery occlusion

There are several reports in the literature on the association between non-arteritic retinal artery occlusion (NA-RAO) and acute ischemic stroke. We investigated the burden of small vessel disease (SVD) and cerebral coincident infarction observed on cerebral magnetic resonance imaging (MRI) in patients with newly diagnosed NA-RAO. In this retrospective, observational, case-series study, consecutive patients with NA-RAO who underwent cerebral MRI within one month of diagnosis between September 2003 and October 2018 were included. The classification of NA-RAO was based on ophthalmologic and systemic examinations. We also investigated the co-incident infarction and burden of underlying SVD, which were categorized as white matter hyperintensity lesion (WMH), cerebral microbleeds (CMB), and silent lacunar infarction (SLI). Among the 272 patients enrolled in the study, 18% presented co-incident infarction and 73% had SVD, which included WMH (70%), CMB (14%), and SLI (30%). Co-incident infarction, WMH, and SLI significantly increased with age: co-incident infarction was observed in 8% of young (< 50 years) patients and 30% of old (≥ 70 years) patients. The embolic etiology of RAO (large artery atherosclerosis, cardioembolism, and undetermined etiology) was significantly associated with the prevalence of SVD (82%: 70%: 64%, P = 0.002) and co-incident infarction (30%: 19%: 8%; P = 0.009). Therefore, high co-incidence of acute cerebral infarction and underlying SVD burden warrant careful neurologic examination and appropriate brain imaging, followed by management of NA-RAO. Urgent brain imaging is particularly pertinent in elderly patients with NA-RAO.

[Visualization of retinal blood flow disturbances in acute retinal ischemia syndrome]

Vascular disorders account for a significant proportion of acute loss of vision. In recent years, scientific and technical progress in ophthalmology has provided new opportunities in the study of vascular pathology, significantly expanding the understanding of their pathogenesis. The article presents a clinical case of a patient with acute retinal ischemia syndrome who had retinal blood flow disturbances studied using optical coherence tomography (OCT) imaging. It demonstrates extensive possibilities of diagnostics of ischemic retinal lesions using OCT angiography that make this method the most informative in terms of evaluating the blood flow at different levels, independently in each vascular plexus.

Oxidative Stress and Vascular Dysfunction in the Retina: Therapeutic Strategies

Many retinal diseases, such as diabetic retinopathy, glaucoma, and age-related macular (AMD) degeneration, are associated with elevated reactive oxygen species (ROS) levels. ROS are important intracellular signaling molecules that regulate numerous physiological actions, including vascular reactivity and neuron function. However, excessive ROS formation has been linked to vascular endothelial dysfunction, neuron degeneration, and inflammation in the retina. ROS can directly modify cellular molecules and impair their function. Moreover, ROS can stimulate the production of inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) causing inflammation and cell death. However, there are various compounds with direct or indirect antioxidant activity that have been used to reduce ROS accumulation in animal models and humans. In this review, we report on the physiological and pathophysiological role of ROS in the retina with a special focus on the vascular system. Moreover, we present therapeutic approaches for individual retinal diseases targeting retinal signaling pathways involving ROS.

Restoration of vision by endovascular revascularization in Takayasu arteritis: A case series

Takayasu arteritis (TA) is a rare, inflammatory vasculitis affecting aorta and its branches. Stenotic occlusive lesions of multiple arch arteries can cause severe cerebral ischemia leading to impaired vision. We present three consecutive young patients of TA with severe diminution of vision on upright posture, where we attempted restoration of sight by improving cerebral blood flow by percutaneous endovascular revascularization. All three patients could be successfully revascularized with substantial improvement in vision. There was no complication. On follow up, one patient developed recurrence of visual symptoms due to restenosis, which was successfully treated by cutting balloon angioplasty. The objective of this case series is to highlight the role of endovascular techniques in reversing visual loss in such situations. <Learning objective: Takayasu arteritis (TA) is an inflammatory vasculitis that can affect arch arteries leading to near complete obliteration and often disabling symptoms such as loss of vision. This case series (3 cases) shows that stent-supported angioplasty is a minimally invasive technique which is safe and effective in restoring impaired vision caused by severe cerebral hypoperfusion in TA.>.

Acute retinal arterial ischemia

Acute retinal arterial ischemia, which includes transient monocular vision loss (TMVL), branch retinal artery occlusion (BRAO), central retinal artery occlusion (CRAO) and ophthalmic artery occlusion (OAO), is most commonly the consequence of an embolic phenomenon from the ipsilateral carotid artery, heart or aortic arch, leading to partial or complete occlusion of the central retinal artery (CRA) or its branches. Acute retinal arterial ischemia is the ocular equivalent of acute cerebral ischemia and is an ophthalmic and medical emergency. Patients with acute retinal arterial ischemia are at a high risk of having further vascular events, such as subsequent strokes and myocardial infarctions (MIs). Therefore, prompt diagnosis and urgent referral to appropriate specialists and centers is necessary for further work-up (such as brain magnetic resonance imaging with diffusion weighted imaging, vascular imaging, and cardiac monitoring and imaging) and potential treatment of an urgent etiology (e.g., carotid dissection or critical carotid artery stenosis). Since there are no proven, effective treatments to improve visual outcome following permanent retinal arterial ischemia (central or branch retinal artery occlusion), treatment must focus on secondary prevention measures to decrease the likelihood of subsequent ischemic events.

Invasive Fungal Sinusitis Presenting as Acute Posterior Ischemic Optic Neuropathy

Invasive fungal sinusitis causes painful orbital apex syndrome with ophthalmoplegia and visual loss; the mechanism is unclear. We report an immunocompromised patient with invasive fungal sinusitis in whom the visual loss was due to posterior ischaemic optic neuropathy, shown on diffusion-weighted MRI, presumably from fungal invasion of small meningeal-based arteries at the orbital apex. After intensive antifungal drugs, orbital exenteration and immune reconstitution, the patient survived, but we were uncertain if the exenteration helped. We suggest that evidence of acute posterior ischaemic optic neuropathy should be a contra-indication to the need for orbital exenteration in invasive fungal sinusitis.

[Neurological manifestations of giant cell arteritis]

The article describes clinical, including neurological manifestations, of giant cell arteritis (GCA) - granulomatous vasculitis of large and medium-sized vessels, predominantly craniofacial, including precerebral and cerebral, arteries. Histopathological features of GCA are illustrated by the schemes of panarteritis and «postarteritis» (proliferative and fibrotic changes in the intima, underlying the development of cerebrovascular disorders). The main clinical manifestations of GCA are described as 3 groups of symptoms: general constitutional symptoms; manifestations of vasculitis of craniofacial, precerebral and cerebral arteries; polymyalgia rheumaticа. The authors present their own version of the taxonomy of visual disturbances in patients with GCA. Diagnostic steps in patients with suggestive signs of GCA are described. Therapeutic regimens of use of glucocorticoids for suggestion/diagnosis of GCA are presented.