###Rationale: RETINAL AERY OCCLUSION Etiology Occlusive disorders of retinal vessels are more common in patients suffering from hypeension and other cardiovascular diseases. Common causes of retinal aery occlusion are:  Atherosclerosis-related thrombosis at the level of lamina cribrosa is the most common cause (75%) of CRAO.  Emboli from the carotid aery and those of cardiac origin account for about 20% cases of CRAO.  Retinal aeritis with obliteration (associated with giant cell aeritis) and periaeritis (associated with polyaeritis nodosa, systemic lupus erythema-tosus, Wegner's granulomatosis and scleroderma) are other causes of CRAO.  Angiospasm is a rare cause of retinal aery occlusion. It is commonly associated with amaurosis.  Raised intraocular pressure may occasionally beassociated with obstruction of retinal aeries for example due to tight encirclage in retinal detachment surgery.  Thrombophilic disorders such as inherited defects of anticoagulants may occasionally be associated with CRAO in young individuals. Clinical features Clinically retinal aery occlusion may present as central retinal aery occlusion or branch aery occlusion. It is more common in males than females. It is usually unilateral but rarely may be bilateral (1 to 2% cases). 1. Central retinal aery occlusion (CRAO).It occurs due to obstruction at the level of lamina cribrosa. Symptoms. Patient complains of sudden painless loss of vision. Signs. Direct pupillary light reflex is absent. On ophthalmoscopic examination retinal aeries are markedly narrowed but retinal veins look almost normal. Retina becomes milky white due to oedema. Central pa of the macular area shows cherry-red spot due to vascular choroid shining through the thin retina of this region. In eyes with a cilioretinal aery, pa of the macular will remain normal . Blood column within the retinal veins is segmented (cattle-trucking). After a few weeks the oedema subsides,and atrophic changes occur which include grossly attenuated thread-like aeries and consecutive optic atrophy . Ref:comprehensive ophthalmology-AK Khurana -4/E pageno:255.

###Answer: OPTION D IS CORRECT.
###Question: Central Retinal aery occlusion is known to be associated with -
###Options:
A. Panophthalmitis
B. Diabetic Retinopathy
C. CMV retinitis
D. Orbital mucormycosis
