CRVO & CRAO

CRVO(CENTRAL RETINAL VEINOUS OCCLUSION)

Classification
  • Central retinal vein occlusion
  1. Non ischemic CRVO (venous stasis retinopathy)
  2. Ischemic CRVO (hemorrhagic retinopathy)
Non-ischemic CRVO
  • Most common type
  • Mild to moderate visual loss
  • No RAPD
  • Fundus examination
  • Early stages
  1. Mild venous congestion & tortuosity
  2. Few superficial flame shaped hemorrhages,
  3. Mild papilledema
  4. Mild or no macular edema
  • Late stages (after 6-9 months)
  1. Sheathing around the main veins
  2. Cilioretinal collaterals around the disc
  3. Cystoid macular edema
  • 50% cases resolve spontaneously with normal vision
  • In the rest, visual loss is due to cystoid macular edema (CME)
  • Intravitreal triamcinolone acetonide is given for CME
Ischemic CRVO
  • Acute complete occlusion of central retinal vein
  • Marked sudden visual loss
  • Relative afferent pupillary defect (RAPD) — present
  • Visual field defects
  • Reduced amplitude of b-wave in ERG
  • Fundus examination
  • Early stages
  1. Massive engorgement, congestion and tortuosity of retinal veins
  2. Whole fundus is full of hemorrhages giving a tomato splash appearance or blood and thunder appearance
  3. Cotton wool spots
  4. Marked macular hemorrhage and edema
  • Late stages
  1. Marked sheathing around veins
  2. Collaterals around the disc
  3. Neovascularization at the disc (NVD) or at the periphery (NVE)
  4. Marked pigmentary changes in the macula & CME
COMPLICATIONS:
  1. Rubeosis iridis
  2. Neovascular glaucoma within 3 months (90 or 100 days glaucoma)
  3. Vitreous hemorrhage
  4. Proliferative retinopathy
TREATMENT:–
  • Panretinal photocoagulation (PRP)
CRAO( CENTRAL RETINAL ARTERIAL OCCLUSION)
ETIOLOGY

  • EMBOLI FROM CAROTID ARTERY
  • VALVULAR HEART DISEASES
  • THROMBUS FROM ARTERIO SCLEROSIS
  • HYPERTENSION
  • ARTERITIS.
  • ORBITAL MUCORMYCOSIS
SYMPTOMS:
  • PAINLESS SUDDEN UNILATERAL LOSS OF VISION.
  • AMAUROSIS FUGAX
SIGNS:
  • LARGER ARTERIES THREAD LIKE AND ARTERIOLES ARE INVISIBLE.
  • VEINS NORMAL .
  • FEW HOURS THE RETINAL LOSES ITS TRANSPARENCY AND BECOME MILKY WHITE.
  • NEOVASCULAR GLAUCOMA
  • CHERRY RED SPOT
  • CATTLE TRACK APPEARANCE.
  • AFTER A WK OR SO THE RETINA RESUMES NORMAL APPEARNECE AND ON BECOMES ATROPHIC AND APPEARS WHITE.
  • NO PL
TREATMENT:
  • DIGITAL MASSAGE.
  • IV ACETAZOLAMIDE.
  • 5% CO2 AND 95% O2 MIXTURE OF 10 MIN.
  • PARACENTSIS.
  • RETROBULBAR INJECTION OF ACETYLCHOLINE.
  • ANTI COAGULANTS. 
Exam Question
  • Cattle track appearance in fundoscopy is due to CRAO
  • Sudden loss of vision is seen in CRAO & CRVO
  • Central Retinal Venous Occlusion (CRVO) from Ocular Ischemic Syndrome can be differentiated on the basis of Tortuous Retinal Vein,Retinal Artery Pressure, Ophthalmodynamometry
  • Cherry red spot on the macula in Fundus examination of a patient presenting with loss of vision is seen in CRAO
  • Rubeosis iridis is seen in CRVO
  • CRAO may be seen in Orbital mucormycosis
  • Neovascular glaucoma can occur in both CRAO & CRVO
  • Vitreous haemorrhage is seen in CRVO
  • Hundred day glaucoma is associated with CRVO
  • CRVO & CRAO ' blood & thunder ' appearance of retina
  • Atherosclerosis in carotid arteries & emboli originating in heart are 2 most common cause

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