Acute Angle-Closure Glaucoma: This condition is characterized by a sudden increase in intraocular pressure, which can cause pupil dilation and blurry vision. It is a medical emergency that requires prompt treatment to prevent permanent vision loss.

Ocular Migraine: Migraines can cause visual disturbances, including blurry vision and pupil dilation, due to the temporary alteration of blood flow to the brain and eyes.
Anticholinergic Toxicity: Medications or substances with anticholinergic properties can cause pupil dilation (mydriasis) and blurry vision by blocking the action of acetylcholine in the eye.
Traumatic Iris Damage: Injury to the iris can lead to pupil dilation and vision problems, including blurriness.

Stroke or Transient Ischemic Attack (TIA): Although less common, a stroke or TIA can present with sudden visual disturbances, including blurry vision and pupil changes. Early recognition is crucial for timely intervention.
Pituitary Apoplexy: A rare but potentially life-threatening condition where a pituitary tumor suddenly hemorrhages or infarcts, leading to acute symptoms that can include visual disturbances and pupil abnormalities.
Cavernous Sinus Thrombosis: A serious condition involving a blood clot in the cavernous sinus, which can cause a range of symptoms including visual disturbances, due to its proximity to several cranial nerves.

Adie Syndrome: A rare neurological disorder characterized by a tonic pupil (which can appear dilated) and reduced or absent deep tendon reflexes. It typically affects young women.
Sympathetic Ophthalmia: A rare, inflammatory condition that can occur after penetrating eye injury, leading to symptoms in the uninjured eye, including vision changes and pupil reactions.
Third Cranial Nerve (Oculomotor Nerve) Palsy: While not extremely rare, when it presents with pupil dilation, it often indicates a more serious underlying cause, such as an aneurysm, which makes it important to investigate thoroughly.