A hypeensive patient was brought to the casualty complaining that he lost his vision suddenly at morning. He didn’t have any pain. Sudden painless loss of vision is seen in all of the following conditions, EXCEPT:
**Core Concept**
Sudden, painless loss of vision is a medical emergency that can be caused by various conditions affecting the eye, including vascular, inflammatory, and traumatic etiologies. In the context of hypertension, conditions like central retinal artery occlusion (CRAO) and central retinal vein occlusion (CRVO) can lead to sudden vision loss.
**Why the Correct Answer is Right**
Central retinal artery occlusion (CRAO) is a condition where the central retinal artery is blocked, leading to sudden vision loss in one eye. This occurs due to embolism or thrombosis in the central retinal artery, which supplies blood to the retina. The retinal ischemia causes sudden painless vision loss, often described as "sudden curtain coming down" or "sudden darkening of vision."
**Why Each Wrong Option is Incorrect**
**Option A:** Ischemic optic neuropathy (AION) is a condition where there is sudden loss of vision due to ischemia of the optic nerve, often seen in hypertensive patients. So, it's not the correct answer.
**Option B:** Central retinal vein occlusion (CRVO) is another condition where there is sudden vision loss, but it is more related to venous obstruction rather than arterial obstruction. However, it still can be associated with sudden painless vision loss.
**Option C:** Anterior ischemic optic neuropathy (AION) is a condition where there is sudden vision loss due to ischemia of the optic nerve head, often seen in hypertensive patients. So, it's not the correct answer.
**Clinical Pearl / High-Yield Fact**
AION and CRAO are both vascular emergencies that require prompt treatment to prevent permanent vision loss. AION often presents with a more gradual loss of vision, whereas CRAO presents with sudden, painless vision loss.
**Correct Answer:** D