CRAO may be seen in

D i.e. Orbital mucormycosis - Most of central retinal aery obstruction (CRAO) are caused by atherosclerotic thrombus formation at or just proximal to the lamina cribrosaQ (-80%) followed by emboli (20%). Inflammation in form of vasculitis (eg varicella infection), optic neuritis or even orbital disease (eg mucormycosis)Q, local trauma and radiation may also cause CRAO. Vascular tropism/ invasion is the hallmark of orbital mucomycosis. This along with thrombosis b/o inflammatory process results in CRAO. In CRAOQ, when obstruction to blood flow is not complete, the flow may be paially restored in the course of a few days in which case gentle pressure upon the globe may break up the column of venous blood (in retinal veins)Q into red beads separated by clear interspaces. The beads move in jerky fashion sometimes in normal direction of blood flow & sometimes in the opposite direction - The "Cattle Truck Appearance". Central retinal aery occlusion characteristically presents with sudden (not gradual) painless loss of vision, cherry red spotQ and cattle truck appearanceQ of retinal veins (usually).