Blepharitis or Conjunctivitis: These are common conditions that can cause discomfort or irritation in one eye, leading to touching or rubbing of that eye. The symptoms can include redness, itching, and discharge, which might prompt a person to touch their eye.

Dry Eye Syndrome: This condition can cause significant discomfort, including a sensation of grittiness or dryness in one eye, prompting the individual to touch or rub it.
Foreign Body Sensation: A small particle or foreign body in the eye can cause intense irritation and the urge to touch or rub the affected eye.
Allergic Conjunctivitis: Seasonal or perennial allergies can lead to itchy, watery eyes, and individuals might touch their eyes due to the discomfort.

Acute Angle-Closure Glaucoma: Although less common, this is a medical emergency that can present with severe eye pain, blurred vision, and redness, potentially causing the individual to touch their eye due to pain. Missing this diagnosis can lead to permanent vision loss.
Corneal Ulcer: A serious infection of the cornea that can cause severe pain, redness, and vision changes. Touching the eye could exacerbate the condition or introduce infection.
Orbital Cellulitis: An infection of the tissues surrounding the eye, which can cause pain, swelling, and vision changes. It requires prompt medical attention to prevent serious complications.

Keratoconus: A progressive eye disease in which the normally round cornea thins and begins to bulge into a cone-like shape, potentially causing discomfort and vision problems that might lead to touching the eye.
Trigeminal Neuralgia: A chronic pain condition that affects the trigeminal nerve, which can cause intense pain in parts of the face, including the eye area, leading to touching or rubbing.
Ocular Migraine: Some types of migraines can cause visual disturbances and pain around the eye, which might result in the individual touching their eye due to discomfort.