The clinical findings differentiating ophthalmic aery occlusion from central Retinal aery occlusion is
Sudden painless loss of vision
Box carring of vessels
Area of retinal whitening
Absence of cherry red spot
Within a few hours of CRAO the retina loses its transparency, becoming opaque and milky-white, especially in the neighbourhood of the disc and macula. At the fovea centralis, where the retina is extremely thin, the red reflex from the choroid is visible and appears as a round cherry-red spot, presenting a strong contrast to the cloudy white background. As choroid derives its blood supply from the ophthalmic aery, in ophthalmic aery occlusion even choroidal circulation is affected and hence a cherry-red spot is not clearly visible
Retina