Which of the following can be a cause of sudden ocular pain?

Sudden ocular pain can be strongly associated with a migraine, which is a type of headache that can present with visual disturbances and pain around the eyes. Migraines can lead to significant discomfort and are often accompanied by other symptoms such as sensitivity to light, nausea, and visual auras. The ocular pain experienced during a migraine may be intense and can sometimes affect only one eye, making it a relevant consideration for sudden onset pain.

In contrast, while allergic reactions, dry eye syndrome, and sinusitis can all cause ocular symptoms, they typically present differently and do not usually result in sudden, severe ocular pain. Allergic reactions often lead to itching, redness, and swelling rather than intense pain. Dry eye syndrome is characterized by a chronic sensation of dryness and irritation, rather than sharp or sudden pain. Sinusitis can cause sinus pressure and discomfort that may radiate to the eyes but is more likely to cause generalized discomfort rather than acute ocular pain. Thus, the association of sudden ocular pain and migraine is well-documented, making it the most appropriate choice in this context.