Migraine with Aura: This is a common condition that can present with visual auras, including blurry or smudged vision, and is often seen in older adults. The new onset of symptoms in an elder man could be due to a late onset of migraines or a change in migraine pattern.

Ocular Migraine: Similar to migraine with aura, but the visual symptoms are typically more pronounced and may not be accompanied by a headache. This could explain the blurry, smudged vision.
Transient Ischemic Attack (TIA) or Minor Stroke: Although less common, TIAs or minor strokes can present with sudden visual disturbances, including blurry vision, and are more likely in older adults due to increased risk of vascular disease.
Dry Age-related Macular Degeneration (AMD): While not typically associated with an aura, AMD can cause sudden changes in vision, including blurriness or smudged vision, especially if there's a sudden progression or involvement of the other eye.

Giant Cell Arteritis: This condition can cause sudden visual loss, including blurry vision, and is a medical emergency. It's crucial to consider this diagnosis in older adults, especially if there are accompanying symptoms like headache, jaw claudication, or scalp tenderness.
Retinal Detachment: Sudden onset of blurry or smudged vision, especially if accompanied by floaters or flashes of light, could indicate a retinal detachment, which requires immediate medical attention.
Posterior Circulation Stroke: Strokes in the posterior circulation can present with visual symptoms, including blurry vision, and are critical to diagnose promptly to initiate appropriate treatment.

Occipital Lobe Seizure: Rarely, seizures originating from the occipital lobe can cause visual auras or disturbances, including blurry or smudged vision, without other typical seizure symptoms.
Vitreous Detachment: While not as immediately dangerous as some other conditions, a vitreous detachment can cause sudden changes in vision, including floaters and blurry vision, and should be evaluated to rule out retinal detachment.
Charles Bonnet Syndrome: This condition involves visual hallucinations in individuals with significant visual loss and could potentially be confused with other causes of blurry or smudged vision, although it's less likely to present with an aura.