What causes the eye to hurt when it blinks?

Several conditions can cause eye pain when blinking. Here are some common causes:

Corneal Abrasion: A corneal abrasion is a scratch on the clear, front surface of the eye (cornea). It can be caused by foreign objects, such as dust, sand, or contact lens wear, and can result in pain, redness, and tearing. Blinking can aggravate the pain as it causes the eyelid to rub against the abrasion.

Blepharitis: Blepharitis is an inflammation of the eyelids, often caused by bacterial infections or clogged oil glands. It can lead to crusty eyelids, redness, swelling, and pain. Blinking can be uncomfortable as the inflamed eyelids rub against the eye.

Stye (Hordeolum): A stye is a small, red, and swollen bump on the eyelid caused by a bacterial infection of the oil glands. It can be painful, especially when blinking, due to the pressure it exerts on the eyelid and the inflammation it causes.

Conjunctivitis (Pink Eye): Conjunctivitis is an inflammation of the conjunctiva, the thin membrane that lines the eyelid and covers the white part of the eye. It can be caused by infections (viral, bacterial, or allergic), allergies, or irritants. Conjunctivitis can result in redness, itching, tearing, and pain, which may worsen with blinking.

Dry Eye Syndrome: Dry eye syndrome occurs when the eyes don't produce enough tears or the tears evaporate too quickly. It can lead to dryness, irritation, and inflammation, causing discomfort, especially when blinking as the dry eye surface is sensitive to touch.

Trichiasis: Trichiasis is a condition where the eyelashes turn inward and rub against the eyeball. This can cause irritation, inflammation, and pain, particularly when blinking as the eyelashes further scratch the cornea.

Corneal Ulcer: A corneal ulcer is an open sore on the cornea, often caused by infections or injuries. It can result in significant pain, redness, sensitivity to light, and blurred vision. Blinking can be painful due to the exposure of the ulcer to the eyelid's touch and the movement of the eyelid over the affected area.

If you experience eye pain when blinking, it's important to see an eye doctor (ophthalmologist or optometrist) for a proper diagnosis and treatment. They can determine the underlying cause and provide appropriate medications or therapies to alleviate the pain and address the underlying condition.