This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Ophthalmology
Gun barrel vision is seen in 
Select and explain. 
A. Closed angle glaucoma, B. Papillaedema, C. Nuclear cataract, D. All of the above
B: Papillaedema
Answer: B: Papillaedema 
Explanation: (B) Papillaedema# GUN BARREL VISION that appears as when looking through a Tunnel or Gun Barrel.> Common Causes:1. Glaucoma (Late)- Chronic open angle glaucoma2. Retinitis pigmentosa3. Post-papillaedema optic atrophy4. Hyaline bodies Drusen) of optic disc5. Bilateral occipital infarcts with macular sparing6. Malingering or Hysteria7. Blood loss8. Hallucinogens9. Extreme fear10. Pituitary stalk tumour11. Severe cataract12. Migraine aura13. Altitude sickness14. Hypoxia> Less common Causes:1. Panic attack2. Exposure to hydraulic fluids3. Intense anger