====== Visual Loss ======

**Visual loss** refers to a **partial or complete decrease in the ability to see**, affecting one or both eyes. It can occur **suddenly or progressively**, and may be **transient or permanent**, depending on the underlying cause.

===== Key Features =====
  * Can be **monocular** (one eye) or **binocular** (both eyes)
  * May involve **central**, **peripheral**, or **global** vision
  * Origin may be **ocular**, **retinal**, **optic nerve**, or **central (cortical)**

===== Common Causes =====
^ Level              ^ Example Conditions                          ^
| **Ocular**         | Cataract, glaucoma, corneal opacities       |
| **Retinal**        | Retinal detachment, diabetic retinopathy    |
| **Optic nerve**    | Optic neuritis, ischemic optic neuropathy   |
| **Central (brain)**| Stroke, occipital lobe tumors, trauma       |

===== Clinical Classification =====
  * **Sudden visual loss** → retinal artery occlusion, optic neuritis
  * **Progressive visual loss** → glaucoma, compressive optic neuropathy
  * **Transient visual loss (amaurosis fugax)** → may suggest vascular origin