Vitreous & Retina




























Retinal Vascular Diseases
Ischemic Central Retinal Vein Occlusion

  • CRVO is the second most common retinal vascular disorder.
  • Patients are usually 50 years or older, but it can occur in younger patients.
  • Two clinical types: perfused (nonischemic) - 75%, and nonperfused (ischemic) - 25%.
  • The second eye can develop vein occlusion in 6-17% of cases.
  • Clinical features:
  • Symptoms: sudden, unilateral, painless visual loss that can range from better than 20/400 in non-ischemic eyes to 20/400 or worse in ischemic eyes
  • Fundoscopic findings:
    • Widespread retinal hemorrhages in all four quadrants, which vary in appearance from a small-scattered retinal hemorrhages to marked confluent hemorrhages
    • Marked dilated and tortuous retinal vessels
    • Cotton-wool spots
    • Optic disc edema, macular edema, and retinal thickening
    • Vitreous hemorrhages may be present
    • A relative afferent pupillary defect (RAPD) can be present in ischemic CRVO
    • Collateral optociliary shunt vessels can develop
    • The fundoscopic findings in nonischemic CRVO are relatively milder than the changes seen in ischemic CRVO
  • Fluorescein angiography:
    • Delayed retinal vascular filling and marked increased retinal arteriovenous transit time
    • Marked hypofluorescence in all the four quadrants, consistent with the blocking effect of retinal hemorrhages
    • Capillary nonperfusion:
      • Ischemic CRVO is characterized by at least 10 disc areas of retinal capillary nonperfusion on the posterior pole
      • Nonischemic CRVO is characterized by less than 10 disc areas of retinal capillary nonperfusion
    • Late leakage
  • Associated conditions include: open-angle glaucoma or various systemic diseases such as diabetes mellitus, systemic hypertension or atherosclerotic cardiovascular diseases.
  • Prognosis:
    • Poor visual prognosis especially if involves a total area of at least 10 disc areas of retinal capillary nonperfusion and poor visual acuity at presentation.
    • Prognosis is better in the nonischemic CRVO especially when initial visual acuity is 20/40 or better or at least better than 20/200.
    • Two-thirds of eyes with ischemic CRVO may develop iris neovascularization or angle neovascularization and subsequent neovascular glaucoma. Retinal neovascularization is uncommon.
    • Nonischemic type may progress to ischemic CRVO in 5-22% of cases.
    • Permanent loss of central vision due to persistent macular edema.
  • Management:
    • Ocular work-up: best-corrected visual acuity, intraocular pressure, slit lamp biomicroscopy, gonioscopy and dilated fundus examination.
    • Monthly visits.
    • Treatment of associated systemic medical condition.
    • Panretinal laser photocoagulation is indicated if neovascularization develops.

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