What are the causes of sudden monocular painless vision loss?

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Last updated: May 24, 2025 • View editorial policy

Differential Diagnosis for Acute Monocular Painless Vision Loss

Single Most Likely Diagnosis

  • Non-arteritic anterior ischemic optic neuropathy (NAION): This condition is the most common cause of acute monocular painless vision loss in older adults, typically occurring in individuals over 50 years old. It results from ischemia of the optic nerve head, leading to sudden vision loss, often upon waking.

Other Likely Diagnoses

  • Central retinal artery occlusion: This is another common cause of acute monocular painless vision loss. It occurs when the central retinal artery becomes occluded, leading to ischemia of the retina and resulting in sudden, severe vision loss.
  • Retinal detachment: Although often associated with symptoms like flashes and floaters, a retinal detachment can cause acute monocular vision loss without pain. It is crucial to diagnose promptly to preserve vision.
  • Optic neuritis: Typically presents with painful vision loss, but in some cases, the pain may be mild or absent. It is an inflammatory condition of the optic nerve that can cause acute vision loss.

Do Not Miss Diagnoses

  • Giant cell arteritis: Although less common, this condition is critical to diagnose due to its potential for causing bilateral blindness if not treated promptly. It can present with acute monocular vision loss, often accompanied by systemic symptoms like headache and jaw claudication.
  • Carotid artery dissection or stenosis: These conditions can lead to embolic events causing vision loss. Identifying and treating them is crucial to prevent further complications, including stroke.

Rare Diagnoses

  • Ocular migraine: Some types of migraines can cause transient, painless monocular vision loss. However, this is less common and usually has a characteristic pattern of visual disturbance.
  • Intraocular tumors (e.g., melanoma): Rarely, an intraocular tumor can cause sudden vision loss by obstructing the visual pathway or causing retinal detachment.
  • Sarcoidosis: This systemic disease can affect the eyes in various ways, including causing optic neuropathy or uveitis, leading to vision loss. It is a rare cause of acute monocular painless vision loss.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.