Central Retinal Artery Occlusion(CRAO)

Central retinal artery obstruction with diffuse superficial retinal whitening in the posterior pole. Note also the marked delay in arterial filling and incomplete venous laminar filling in the later phase of the study. 

  • Typically unilateral.
  • More commonly affect older people in their mid-sixties, but can also occur in younger patients.
  • Most common cause: systemic hypertension.
  • Other etiologies: diabetes mellitus, emboli from valvular heart diseases, carotid atherosclerosis and DVT, circulatory compromise, coagulopathies, collagen vascular diseases, other vasculitides and trauma.

Clinical features:

  • Symptoms:
    • Sudden, painless loss of vision
    • May have a history of amaurosis fugax
  • Signs:
    • Normal anterior segment in acute cases
    • Pale, whitening, swelling retina especially in the posterior pole
    • Cherry red spot as a presentation of orange reflex from the intact choroidal vasculature beneath the foveola surrounded by the retinal pallor
    • Afferent pupil defect is usually present
    • Emboli may be seen
    • After 4-6 weeks, the cloudy swelling retinal commonly resolves, leaving a pale optic disc, attenuated retinal vessels, segmentation or "boxcarring" of the blood column
    • In most cases, neovascularization of the iris usually present by this time
    • Final visual acuity is most often worse than 20/400
    • Visual acuity of better than 20/40 may be achieved with patent cilioretinal artery

Fluorescein angiography demonstrates:

  • Delay in retinal arterial filling and arteriovenous transit time
  • Segmentation of the blood column
  • Choroidal vascular filling is usually normal

Management:

  • Thorough evaluation of systemic etiology.
  • May consider the following treatment to lower the intraocular pressure: ocular massage, anterior chamber paracenthesis.
  • Other treatments may include: oral vasodilator and systemic anticoagulants.
  • Panretinal photocoagulation in the presence of iris neovascularization.