In any patient with visual loss it is imperative to ask 2 questions.

1. Is the visual loss in one of both eyes? This is because if the visual loss in monocular (one eye) it is likely related to an eye problem affecting the cornea, anterior chamber, vitreous, retina or optic nerve. If it is binocular, it likely affects the chiasm or the occipital lobe.
2. Is there pain associated with the visual loss? If there is pain, it is likely related to a problem in the front of the eye, including such problems as corneal abrasions and infections, inflammation in the eye and angle closure glaucoma.

In this particular patient a dilated examination showed that the patient had significant areas of “cloudy swelling” (this is what ophthalmologists call retinal whitening due to thickening of the superficial axons of the retina). Cloudy swelling is indicative of retinal artery ischemia. This patient was also noted to have some thinning of the retinal artery (the normal vein to artery ratio is 3:2). A chalky-white embolus was noted at the level of the central retinal artery as it exited the optic nerve. The patient was diagnosed with a retinal artery occlusion.