SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Central retinal artery

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PURPOSE.: This study aimed to evaluate the changes in retrobulbar blood flow by using color Doppler sonography in patients who had undergone intravitreal ranibizumab injection for neovascular age-related macular degeneration (AMD). METHODS.: The study comprised 37 AMD patients who had undergone intravitreal 0.5 mg ranibizumab injection. The ophthalmic artery, central retinal artery, and short lateral posterior ciliary artery of both eyes of patients were evaluated by color Doppler sonography. Peak systolic velocity, end-diastolic velocity, and resistance index were calculated before injection, and after injection on day 7 and day 30. The pre- and postinjection values were compared using Wilcoxon signed rank test. RESULTS.: In a comparison with the preinjection values of peak systolic velocity, end-diastolic velocity, and resistance index, the postinjection values at both day 7 and day 30 showed no statistically significant difference in ophthalmic artery, lateral posterior ciliary artery, and central retinal artery (p > 0.05). Similarly, for the same parameters, pre- and postinjection values in the uninjected fellow eye showed no statistically significant difference (P > 0.05). CONCLUSIONS.: Intravitreal ranibizumab injection for neovascular AMD does not cause a significant change in the retrobulbar blood flow in either the injected eye or the fellow eye. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound 2013.

Concepts: Statistical significance, Retina, Eye, Medical ultrasonography, Macular degeneration, Arteries of the head and neck, Central retinal artery, Ophthalmic artery

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The rationale behind hyperacute fibrinolytic therapy for cerebral and retinal arterial occlusion is to rescue ischaemic cells from irreversible damage through timely restitution of tissue perfusion. In cerebral stroke, an anoxic tissue compartment (the “infarct core”) is surrounded by a hypoxic compartment (the “ischaemic penumbra”). The latter comprises electrically-silent neurons that undergo delayed apoptotic cell death within 1-6hrs unless salvaged by arterial recanalisation. Establishment of an equivalent hypoxic compartment within the inner retina following central retinal artery occlusion (CRAO) isn’t widely acknowledged. During experimental CRAO, electroretinography reveals 3 oxygenation-based tissue compartments (anoxic, hypoxic and normoxic) that contribute 32%, 27% and 41% respectively to the pre-occlusion b-wave amplitude. Thus, once the anoxia survival time (≈2hrs) expires, the contribution from the infarcted posterior retina is irreversibly extinguished, but electrical activity continues in the normoxic periphery. Imbetween these compartments, an annular hypoxic zone (the “penumbra obscura”) endures in a structurally-intact but functionally-impaired state until retinal reperfusion allows rapid recovery from electrical silence. Clinically, residual circulation of sufficient volume flow rate generates the heterogeneous fundus picture of “partial” CRAO. Persistent retinal venous hypoxaemia signifies maximal extraction of oxygen by an enduring “polar penumbra” that permeates or largely replaces the infarct core. On retinal reperfusion some days later, the retinal venous oxygen saturation reverts to normal and vision improves. Thus, penumbral inner retina, marginally oxygenated by the choroid or by residual circulation, isn’t at risk of delayed apoptotic infarction (unlike hypoxic cerebral cortex). Emergency fibrinolytic intervention is inappropriate, therefore, once the duration of CRAO exceeds 2hrs.

Concepts: Blood, Myocardial infarction, Atherosclerosis, Blood vessel, Stroke, Retina, Necrosis, Central retinal artery

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This case illustrates an oculoischaemic syndrome presenting with iris neovascularisation in a patient with established diabetic retinopathy. It highlights the importance of considering the differential diagnosis of rubeosis in all patients, including those with an underlying vascular pathology. Moreover, it urges clinicians to consider the sequelae of a compromised vascular system, such as the iatrogenic central retinal artery occlusion as a result of intravitreal injections. Early diagnosis not only informs correct ophthalmic treatment, but is crucial in preventing ischaemic stroke and, therefore, reducing the risk of systemic morbidity and mortality.

Concepts: Medical terms, Diabetes mellitus, Hospital, Stroke, Retina, Central retinal artery, Ophthalmic artery, Rubeosis iridis

2

IMPORTANCE Dermal injection of cosmetic fillers can lead to irreversible blindness when injected in the forehead, and this possible adverse effect is not typically mentioned to patients. OBSERVATIONS Vision loss from central retinal artery occlusion occurring, after cosmetic facial enhancement, was irreversible in 3 patients. However, 1 patient had a small amount of recovery with aggressive therapy. CONCLUSIONS AND RELEVANCE Cosmetic facial fillers are not approved for use in the forehead, but off-label use for enhancement in this region is common. To our knowledge, there have been no prior reports of blindness caused by filler injected into the forehead. We present findings of central retinal artery occlusion due to fillers in 3 patients shortly after their cosmetic procedures. The filler presumably enters the central retinal artery via the rich external-internal carotid anastomoses and becomes embedded in the retinal tissues, potentially leading to irreversible and severe vision loss. Physicians performing cosmetic enhancement procedures involving facial fillers need to be aware of this potential complication and should include significant vision loss as a possible rare complication.

Concepts: Retina, Arteries of the head and neck, Central retinal artery

1

Central retinal artery occlusion (CRAO) is an ophthalmologic emergency that can result in blindness. At present, no proven therapy for CRAO exists. Treatment with fibrinolytic agents has shown promise but remains of unproven benefit.

Concepts: Retina, Central retinal artery

0

The critical time from onset of complete occlusion of the central retinal artery (CRA) to functionally significant inner retinal infarction represents a window of opportunity for treatment and also has medical-legal implications, particularly when central retinal artery occlusion (CRAO) complicates therapeutic interventions. Here, we review the evidence for time to infarction from complete CRAO and discuss the implications of our findings.

Concepts: Retina, Central retinal artery

0

We report a case of central retinal artery occlusion (CRAO) with cilioretinal sparing following orbital biopsy, with a review of the literature regarding post-orbital surgery CRAO. The case highlights the importance of routine post-operative observations following orbital surgery, the significance of recognizing CRAO as a potential complication, and its management.

Concepts: Retina, Central retinal artery

0

To determine the incidence of ischemic cerebral stroke in the 6-month periods preceding and following acute central retinal artery occlusion (CRAO) among Medicare beneficiaries.

Concepts: Cohort study, Stroke, Retina, Central retinal artery

0

A 25-year-old male patient presented to the emergency department with the chief complaint of sudden blindness and was found to have suffered bilateral central retinal artery occlusion (CRAO). This process is most commonly the result of a thrombus or embolus that occludes the retinal artery, and normally presents in a single eye in patients older than 65 who are predisposed to vascular disease. Diagnosis relies most heavily upon funduscopic exam. Potential treatments involve ocular massage, acetazolamide, anterior chamber paracentesis and systemic or local fibrinolysis. Despite these interventions vision is often significantly and permanently impaired. This case underscores the importance of the emergency physician’s ability to promptly perform and interpret the funduscopic exam in order to diagnose and evaluate CRAO.

Concepts: Myocardial infarction, Medical terms, Hospital, Physician, Retina, Central retinal artery

0

To describe a case of transient, partial, central retinal artery occlusion with paracentral acute middle maculopathy optical coherence tomography presentation in a young healthy patient after ingestion of the synephrine-containing supplement, Havok.

Concepts: Retina, Central retinal artery