By Adam H. Rogers, MD, and Jay S. Duker, MD (Auth.)
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Branch Retinal Vein Occlusion (continued) Fig. 4 Prominent capillary non-perfusion in the superior temporal quadrant that extends to the superior edge of the fovea in a BRVO that is more chronic in nature. The intraretinal hemorrhage has cleared, and capillary shunt vessels are present in the macula crossing the median raphe. 35 Central Retinal Vein Occlusion Key Facts • Common retinal vascular disorder • Occurs more often in persons over age 50 • Thrombosis of the central retinal vein at the level of the lamina cribrosa causes the central retinal vein occlusion (CRVO) • Venous occlusion elevates venous pressure, resulting in stagnation of arterial blood ﬂow and ultimate retinal hypoxia damaging the retina • Associated with hypertension and diabetes • Glaucoma is a common associated ocular disease • May be categorized as either ischemic or non-ischemic • Non-ischemic CRVO is more common, occurring in 75% of all cases • Bilateral in 10% of patients Clinical Findings SECTION 3 • Vascular Obstructions • Intraretinal hemorrhage with dilated and tortuous retinal veins in all four quadrants • Cotton wool spots • Optic disc swelling • Macular edema • Capillary non-perfusion • Neovascularization of retina or iris • Neovascular glaucoma • Vitreous hemorrhage • Relative afferent pupillary defect (RAPD) in ischemic CRVO • Venous collateral vessels at optic nerve (late ﬁnding) Ancillary Testing • Pupillary examination to evaluate for RAPD • Gonioscopy for evaluating the iris and angle for neovascularization • Fluorescein angiography is limited in early CRVO from blockage from retinal hemorrhage but can evaluate retinal circulation, non-perfusion, and retinal neovascularization • Electroretinogram may show a decreased b : a ratio Differential Diagnosis • Ocular ischemic syndrome • Diabetic retinopathy • Hypertensive retinopathy • Radiation retinopathy • Carotid cavernous or dural sinus ﬁstula Treatment • Medically treat any underlying diabetes and hypertension • Treat any underlying glaucoma • Panretinal photocoagulation (PRP) of the peripheral retina when neovascularization of the iris, angle, or retina is present • PRP before formation of neovascularization is not beneﬁcial and is advised only if there is considerable ischemia and close follow-up is not possible • Focal laser photocoagulation is beneﬁcial in reducing macular edema but has not been proven beneﬁcial in improving visual acuity • Intravitreal corticosteroids and intravitreal anti-VEGF injections have shown beneﬁt in limited case reports Prognosis 36 • About 34% of all eyes with perfused CRVO convert to non-perfused within 3 years • Iris or angle neovascularization is found in about 16% of eyes • Increasing retinal vascular non-perfusion and decreasing visual acuity are the strongest predictors • A natural history study published by the Central Vein Occlusion Study Group reported that initial visual acuity is the main predictor of ﬁnal visual outcome A B Fig.
Central Retinal Vein Occlusion B 37 Branch Retinal Artery Occlusion Key Facts • • • • • • • Rare event occurring less frequently than central retinal artery occlusion Men affected more commonly than women Most commonly occurs in sixth and seventh decades Right eye affected more commonly than the left eye Temporal retina more commonly affected than nasal retina Embolus is the most common cause Risk factors include: • diabetes • hypertension • hyperlipidemia • cardiac valvular disease • carotid artery disease • smoking • Giant cell arteritis may be the etiology in 1–2% of cases Clinical Findings • • • • SECTION 3 • Vascular Obstructions Central visual acuity may be diminished or normal Visual ﬁeld loss occurs in the area corresponding to the retinal ischemia Pupils may be normal or show a relative afferent defect Acute clinical ﬁndings: • retinal whitening and edema in area of ischemia • embolus • Chronic clinical ﬁndings: • retinal whitening will resolve even if recanalization of the obstructed artery does not occur • loss of nerve ﬁber layer in area of ischemia, which may not be evident on physical examination • sheathing of the arteriole in the area of previous obstruction • arteriolar collaterals Ancillary Testing • Visual ﬁeld test • Fluorescein angiography shows diminished ﬂow in the area of the obstructed arteriole, with delayed ﬁlling in the adjacent veins supplied • Late frames in the angiogram may show staining of the arteriole at the point of obstruction • Carotid ultrasound to evaluate for carotid stenosis • Cardiac echography to evaluate for cardiac and aortic source of emboli • Systemic medical evaluation of other etiologies should be considered in younger patients and includes: • giant cell arteritis • pancreatitis • sickle cell disease • amniotic ﬂuid embolus • systemic clotting disorders • homocystinuria • Kawasaki disease Differential Diagnosis • Central retinal artery occlusion • Cotton wool spot • Inﬂammatory or infectious chorioretinitis Treatment • No proven ocular therapy exists • Digital massage and anterior paracentesis may dislodge the embolus to a more distal arteriole, but each maneuver is rarely performed given the low success rate • Stroke work-up by the neurology service and prophylaxis with systemic anticoagulation should be instituted immediately, especially in elderly patients • Discontinue smoking and oral contraceptives • Intravenous or oral corticosteroids should be started if giant cell arteritis is suspected Prognosis • Visual ﬁeld defects are permanent • Most patients retain 20/40 or better visual acuity unless the fovea is affected • Neovascularization uncommon 38 Branch Retinal Artery Occlusion Fig.
16 Angioid streaks delineated in an eye after indocyanine green administration. Fig. 17 Peau d’orange appearance is visible in the temporal aspect of the macula in this patient with angioid streaks and pseudoxanthoma elasticum. 29 Section 3 Vascular Obstructions Branch Retinal Vein Occlusion 32 Central Retinal Vein Occlusion 36 Branch Retinal Artery Occlusion 38 Cilioretinal Artery Occlusion 40 Central Retinal Artery Obstruction 42 Coats Disease 46 Idiopathic Juxtafoveal Telangiectasia 50 Radiation Retinopathy 52 Sickle Cell Retinopathy 54 Hypertensive Retinopathy 58 Ocular Ischemic Syndrome 62 Retinal Arterial Macroaneurysm 64 Purtscher Retinopathy 66 Terson Syndrome 68 HIV Retinopathy 70 Hematologic Disorders 72 Branch Retinal Vein Occlusion Key Facts • • • • • • Common cause of acute visual loss or visual ﬁeld deﬁcit Typically unilateral but may be bilateral in 5–10% of patients Men and women equally affected Most often occurs in elderly persons More common than central retinal vein occlusion Hypertension and arteriosclerosis are the major associations Clinical Findings SECTION 3 • Vascular Obstructions 32 • Decreased visual acuity • Visual ﬁeld defect corresponding to area of venous occlusion • Intraretinal hemorrhage in the distribution along the obstructed retinal vein, with the apex of the hemorrhage at an arteriovenous crossing • Macular edema • Capillary non-perfusion and macular ischemia • Retinal neovascularization • Vitreous hemorrhage • Collateral vessel formation in chronic disease Ancillary Testing • Fluorescein angiography (FA) to evaluate capillary non-perfusion and areas of retinal ischemia • Optical coherence tomography to evaluate and monitor macular edema Differential Diagnosis • • • • • Diabetic retinopathy Hypertensive retinopathy Idiopathic juxtafoveal telangiectasia Radiation retinopathy Ocular ischemic syndrome Treatment • Laser treatment is guided by the Branch Retinal Vein Occlusion Study Group • Grid laser for macular edema: • apply to eyes with 20/40 or worse vision for ≥3 months with intact foveal circulation • delay treatment if the macular hemorrhage is too dense to enable photocoagulation or evaluate retinal circulation on FA • withhold if decreased vision is due to capillary non-perfusion • Panretinal photocoagulation to the peripheral non-perfused retina as visualized on FA when retinal neovascularization is present • Intravitreal corticosteroids in eyes with macular edema, either as a primary treatment or in eyes refractory to grid laser photocoagulation • Intravitreal anti–vascular endothelial growth factor (VEGF) therapy for macular edema, either as a primary treatment or in eyes refractory to grid laser photocoagulation • Sheathotomy during pars plana vitrectomy to sever the common sheath shared by the arteriole and vein at the level of the obstruction to free the artery from compressing the vein B A Fig.