Differential Diagnosis

The patient's symptoms of a black spot with a grey film in one eye, which appeared a month after a normal eye exam, can be approached by considering the following categories:

• Single most likely diagnosis:
  • Vitreous detachment or floaters: This is a common condition where the vitreous gel in the eye separates from the retina, causing floaters or a grey film. The sudden onset of a black spot could be a floater that is particularly noticeable.
• Other Likely diagnoses:
  • Retinal tear or detachment: Although less common, a retinal tear or detachment could cause sudden vision changes, including a grey film or black spots. The patient's recent normal eye exam makes this less likely but still possible.
  • Migraine with aura: Some people experience visual auras during migraines, which can include grey films or black spots. However, these are usually accompanied by other migraine symptoms.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
  • Retinal vein or artery occlusion: These are medical emergencies that can cause sudden vision loss, sometimes described as a curtain or grey film descending over the eye. Prompt treatment is necessary to preserve vision.
  • Optic neuritis: Inflammation of the optic nerve can cause sudden vision loss, pain with eye movement, and changes in color perception. It's a condition that requires prompt medical attention.
• Rare diagnoses:
  • Ocular melanoma: Although rare, a melanoma in the eye could cause visual disturbances, including floaters or a grey film, especially if it affects the retina or vitreous.
  • Intraocular inflammation (uveitis): This can cause a variety of symptoms, including floaters, pain, and changes in vision. It's less common but should be considered in the differential diagnosis.

Given the acute onset of symptoms, it would be prudent for the patient to seek immediate medical attention, preferably at an emergency room or an urgent care facility that can provide ophthalmologic evaluation, to rule out serious conditions such as retinal detachment or occlusion.