From the front of the eye to the back of the eye: Differential diagnosis of acute persistent vision loss by anatomy.

Cornea: Keratitis (Infectious or non-infectious) – Keratitis produces a sharp superficial pain,
Corneal edema: Acute glaucoma (primarily) – acute glaucoma produces a deep brow ache with n/v
Anterior chamber: Hyphema (i.e. blood in the anterior chamber). Spontaneous or traumatic.
Lens: Changes in the crystalline lens. Caused by thickening, clouding or dislocation of the lens.
Vitreous Hemorrhage. Spontaneous or traumatic.
Uveitis: Uveitis is the general term for inflammation inside the eye. “Biomicroscopic examination reveals WBCs in the anterior chamber, vitreous space, or both. A hypopyon (WBC accumulation) may form in the anterior chamber. Corneal edema and a decreased red reflex may also be present.”
Retinal problems: Retinal vascular occlusion (CRAO, CRVO); Retinal detachment; Acute maculopathy
Problems of the neural visual pathway.
-Optic neuropathy (from Ischemia, inflammation, or infectious process)
-Papilledema (from Elevated intracranial pressure)
-Chiasmal disorders (Pituitary apoplexy {primarily})
-Retrochiasmal disorders (Brain lesions in the visual pathway)
Other causes
Trauma can cause of any of the above disorders
Acute glaucoma: Vision loss due to corneal edema and/or optic nerve ischemia in the setting of severely elevated intraocular pressure
Functional visual loss

CRAO: central retinal artery occlusion; CRVO: central retinal vein occlusion.

Further reading
uptodate.com/contents/approach-to-the-adult-with-acute-persistent-visual-loss

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