Dry eye or eye strain: This is a common condition that can cause sharp, transient pain behind the eye, especially if it occurred only once and lasted for seconds. Activities like prolonged reading, computer use, or other visually demanding tasks can lead to this condition.

Scleritis or episcleritis: Inflammation of the sclera or episclera can cause sharp pain, but it usually lasts longer than seconds and is accompanied by redness and tenderness to the touch.
Migraine or cluster headache: Although these conditions can cause severe pain, they typically have other associated symptoms like photophobia, nausea, or autonomic features, and the pain usually lasts longer than a few seconds.
Trigeminal neuralgia: This condition involves sudden, severe, shock-like pain around the eyes, lips, or nose, but it's more common in older adults and can be triggered by specific factors.

Acute angle-closure glaucoma: This is a medical emergency that can cause severe eye pain, but it's usually accompanied by blurred vision, redness, nausea, and vomiting. Missing this diagnosis can lead to permanent vision loss.
Cavernous sinus thrombosis: A rare but potentially life-threatening condition that can cause pain behind the eye, along with other symptoms like fever, ptosis, and cranial nerve palsies.
Temporal arteritis: This condition can cause severe headache and pain behind the eye, especially in older adults, and can lead to blindness if not treated promptly.

Ocular or orbital tumors: Although rare, tumors in or around the eye can cause pain, but this is usually a more chronic symptom accompanied by other signs like proptosis or vision changes.
Idiopathic stabbing headache: A rare condition characterized by brief, stabbing pains in the head or eye, but it's typically not as severe as other conditions listed here.
Optic neuritis: Inflammation of the optic nerve can cause pain behind the eye, especially with eye movement, but it's usually accompanied by vision loss or changes in color perception.