There are many causes of sudden eye pain, including the following:

1. Dry eyes

The dry eye one of the leading causes of sudden eye pain occurs as a result of fatigue eyes and prolonged use of electronic devices, so that it leads to a lack of secretion of tears and thus eye pain, itching, redness, and blurred vision.

2. Allergy

Some people may suffer from allergies to some substances, such as: pollen, mold, dust or cosmetics, which leads to swelling and redness of the eyes, many tears, severe itching and pain as well.

3. Corneal abrasion

The cornea is the transparent part of the eye located in the front part. Scratching the surface of the cornea as a result of injuries resulting from the entry of a foreign object into the eye or as a result of the misuse of contact lenses can lead to inflammation or ulceration of the cornea, which results in severe pain with blurred vision and sensitivity to light.

4. Infections and infections

Inflammation of any part of the eye leads to sudden eye pain, and the most prominent eye infections and infections include the following:

• Beggar eye: It occurs as a result of inflammation of the sebaceous glands in the eye, and appears in the form of a boil that forms inside or outside the eyelid.
• Conjunctivitis: It means inflammation of the conjunctiva of the eye, which is a thin tissue covering the white area of ​​the eye, which leads to redness with itching, pain and swelling of the eye.
• Blepharitis : It is the inflammation resulting from a bacterial infection of the eyelashes follicles, which leads to swelling and redness of the eyelid with itching and crusting of the eyelids.
• Dacryocystitis: This is usually caused by a bacterial infection in the tear drainage area in the corner of the eye, which leads to pain, redness, and the secretion of tears and pus.
• Scleritis: The sclera is the white area of ​​the eye that is directly connected to the muscles, and its inflammation causes severe sudden pain.
• Uveitis: The iris is the colored part of the eye and its inflammation causes pain, redness and blurred vision.
• Orbitis: It is the inflammation that affects the muscles and fat surrounding the eye, and it results in great pain when moving the eye in addition to swelling and heat.

5. Infection with some diseases

In some cases, having some diseases may be one of the causes of sudden eye pain, including the following:

• Glaucoma: It is high intraocular pressure, a chronic disease that damages the optic nerve, and usually leads to pain, blurred vision, and seeing halos and black dots.
• Cluster headache: It is a type of headache and is usually concentrated on one side of the head, accompanied by headache, redness of the eyes and an increase in the secretion of tears sometimes.
• Optic neuritis: inflammation of the main nerve that extends from the eye to the brain and usually leads to vision loss.
• Other diseases: including aneurysm, and eye cancer . 

Sudden eye pain diagnosis

Sudden eye pain can be diagnosed through the following methods:

1. Eye examination

Vision is checked in several ways, including the use of light or drops to dilate the eye or devices to measure intraocular pressure.

2. Radiographs

The doctor may use radiological images through computed tomography or magnetic resonance imaging.

3. Comprehensive blood test

Blood tests are only done in cases where the doctor suspects that eye pain is a sign or symptom of another systemic disease. 

How to treat sudden eye pain 

Treatment depends on the cause, so that dryness and allergies can be treated using moisturizing and anti-allergic drops and ointments, while infection and inflammation are treated through antibiotics, viral or anti-inflammatory drugs such as steroids, depending on the patient’s situation.

In the case of glaucoma, antihypertensive eye drops are used, and sometimes surgery may be the solution 

source : wikipedia