Migraine: This condition is characterized by acute, severe head pain, often accompanied by visual disturbances such as blurry vision. The pain can sometimes radiate to the jaw, especially if the migraine involves the trigeminal nerve. The combination of head pain and blurry vision, along with jaw pain, makes migraine a plausible diagnosis.

Tension Headache: While typically less severe than migraines, tension headaches can cause significant discomfort and may be accompanied by jaw pain due to teeth clenching or grinding. Blurry vision can occur due to tension in the neck and scalp muscles.
Temporomandibular Joint (TMJ) Disorder: TMJ disorders can cause jaw pain and, due to referred pain patterns, may also lead to headaches. Blurry vision could be a secondary effect of pain or tension, though it's less directly related.
Sinusitis: Acute sinus infections can cause head pain, particularly in the facial area, and may lead to blurry vision if the sinuses around the eyes are affected. Jaw pain could be referred from the facial sinuses.

Stroke or Transient Ischemic Attack (TIA): Although less common, a stroke or TIA can present with sudden onset of head pain, visual disturbances (including blurry vision), and jaw pain. The potential for severe and permanent neurological damage makes this a critical diagnosis not to miss.
Giant Cell Arteritis: This condition can cause severe head pain, visual disturbances (including blurry vision), and jaw claudication (pain when chewing). Given its potential to lead to blindness if not promptly treated, it's a diagnosis that must be considered.
Acute Angle-Closure Glaucoma: Characterized by sudden, severe eye pain, blurry vision, and sometimes head pain, this is an ophthalmic emergency. Jaw pain might be less directly related but could occur due to the severe pain and associated muscle tension.

Trigeminal Neuralgia: A condition that affects the trigeminal nerve, causing intense pain in the face, which could be interpreted as head or jaw pain. Visual disturbances are less common but could occur due to the severe pain causing secondary effects.
Occipital Neuralgia: Involves the nerves that run from the base of the skull to the scalp and can cause head pain. While less likely to cause jaw pain directly, the severe head pain could lead to secondary muscle tension causing jaw discomfort. Blurry vision could be a result of the pain's severity.
Arteriovenous Malformation (AVM): A rare condition where there's an abnormal connection between arteries and veins, which can cause a variety of symptoms including head pain, visual disturbances, and potentially jaw pain if the AVM is located in a relevant area.