Pain Behind Left Eye: 13 Common Causes & What to Do

Pain behind the left eye can be a result of vision problems, like hypermetropia or astigmatism, optic nerve inflammation, cornea inflammation or uvea inflammation. Left eye pain can also be caused by a foreign body in the eye or burning of the cornea. Pain can affect just the left eye or both eyes, and can range from mild to intense. It can also worsen with eye movements or focusing. 

Depending on the underlying cause, left eye pain can be accompanied by other symptoms, like redness, burning, increased light sensitivity, decreased vision, itching or headache. 

It is important to see an ophthalmologist if you experience eye symptoms, so that the underlying cause can be identified and treated. Treatment may include corrective vision glasses, eye drops or other medications. 

The main causes of pain behind the left eye are:

1. Vision problems

Vision problems, like astigmatism, hypermetropia, myopia or presbyopia, can cause excess straining of the eyes when focusing. This can lead to frequent headaches and eye pain, which can affect just one or both eyes. 

Vision problems can occur in anybody and can be a result of trauma, injuries, chronic diseases or natural aging. 

What to do: You should consult an ophthalmologist for a vision assessment. If necessary, the doctor may prescribe corrective glasses, contact lenses or even surgery to improve focusing capacities. 

2. Pink eye

Pink eye, or conjunctivitis, can affect just the left eye, but can easily transmit to the right eye (and vice cersa). Symptoms include pain in the affected eye, redness, burning, sensitivity to light, and excessive tearing. 

Pink eye is an inflammation of the conjunctiva, the thin, clear lining that lines the eyeball. It is usually caused by a bacterial, viral or fungal infection, but can also emerge with allergies. 

What to do: Treatment for pink eye should be oriented by an ophthalmologist, who may prescribe eye drops, anti-inflammatory ointments or antibiotics.  

3. Using contact lenses

Using contact lenses can also cause eye inflammation, especially if they are not properly cleaned. Dirty lenses can lead to bacterial, viral or fungal contamination, leading to infection and inflammation in one or both eyes. This can cause pain, redness and itching.

In more serious cases, contact lenses can even lead to ulcers or intense cornea inflammation. 

What to do: Treatment for inflammation or infections secondary to contact lens contamination should be oriented by an ophthalmologist. Treatment depends on the type of infection or inflammation. To prevent eye damage, you should clean your contact lenses as per manufacturer instructions. 

4. Stye

A stye is an inflammation of a small gland in the eyelid. It can cause eye pain, eyelid swelling, redness, discomfort and itching in the area. 

Stays mainly emerge due to bacterial infections, seborrhea, acne or chronic blepharitis. 

What to do: Styes usually disappear within 3 to 5 days on their own without any specific treatment. You can apply warm compresses to the affected eye to reduce swelling and relieve discomfort. If the sty does not improve, you should see a doctor for treatment with an antibiotic ointment or eye drops. 

5. Foreign body in the eye

The presence of a foreign body in the eye is one of the most common causes of pain behind the left eye, although it can also affect the right eye or both eyes at the same time. Usually, the foreign body are specks, dust, dirt, make-up or an eyelash. 

Eye pain can be accompanied by other symptoms, like irritation, redness or tearing. 

What to do: Blinking your eye several times can help to clear the foreign body out of the eye naturally. You can also cleanse the eye with saline to facilitate removal. Avoid rubbing your eye to prevent damage or corneal orritation. If you are unable to clear the foreign body, you should see your doctor, as leaving it untreated can cause more serious injuries. 

6. Glaucoma

Glaucoma is characterized by an increase in ocular pressure. It generally does not cause symptoms, although angle closure glaucoma can lead to eye pain, headache or nausea. 

Glaucoma can also lead to optic nerve damage e progressive vision loss that can lead to blindness, particularly if the condition is not diagnosed and left untreated. 

What to do: You should see an ophthalmologist for testing and diagnosis. The doctor may prescribe eye drops, laser therapy or even surgery, depending on your symptoms and severity. 

7. Meibomitis

Meibomitis is a small, painful lump that can appear on the eyelid. It typically has a yellow spot in the middle, similar to a pimple, and can cause pain, swelling, redness, the sensation of something in your eye, itching, and blurry vision.

This condition is caused by an inflammation or infection of the Meibomian glands, located in the upper and lower eye lids. They are responsible for producing the oil that lubricates the eyes and prevents tears from evaporating quickly. 

Generally, meibomitis can emerge due to contact lens use, exposure to dry environments or air conditioning, hormonal changes and rosacea.

What to do: Treatment for meibomitis should be prescribed by an ophthalmologist. Treatment depends on the severity of symptoms, and can involve applying warm compresses, using eye drops, corticosteroid medications or antibiotics. More serious cases may require surgical intervention. 

8. Uveitis 

Uveitis is an inflammation of the uvea, which is made-up of the iris, ciliary body and choroid. It can affect the left eye, right eye or both eyes, and leads to symptoms like eye pain, redness, light sensitivity or blurry vision. These symptoms can emerge suddenly and worsen very quickly, or they can come on gradually. 

This eye inflammation can occur due to autoimmune diseases or infectious diseases, like rheumatoid arthritis, sarcoidosis, syphilis, onchocerciasis or Hansen’s disease. 

What to do: You should consult an ophthalmologist to start treatment, which may involve anti-inflammatory eye drops, corticosteroids or antibiotics. More serious cases may require surgical intervention. 

9. HSV keratitis

HSV (herpes simplex virus) keratitis is an inflammation of the cornea caused by the herpes simplex virus. It causes symptoms like intense pain, burning, redness, increased light sensitivity, tearing or blurry vision. Many patients may also experience blisters or ulcers close to the eye.

This type of corneal infection can occur in the left eye and transmit to the right eye, especially if you directly touch herpes blisters in one eye and touch your other eye. 

What to do: You should see an ophthalmologist urgently to start treatment and prevent complications like blindness. Generally, the doctor may prescribe eye ointments, antivirals, or antibiotics. 

10. Iritis

Iritis is an inflammation of the iris, which is the colored part of the eye that can lead to pain within the eye, redness, increased light sensitivity or vision loss. 

Although this condition is not common, it can affect the left eye or both eyes. It is generally caused by injury, infections, sarcoidosis, juvenile rheumatoid arthritis or even medications, like rifabutin or cidofovir.  

What to do: Iritis treatment should be oriented by an ophthalmologist, who may prescribe corticosteroid eye drops or eye drops that dilate the pupils in order to relieve symptoms. Iritis triggered by other health conditions can resolve once the underlying cause is addressed. 

11. Optic neuritis

Optic neuritis is an inflammation of the optic nerve, which connects the brain to the eye. Swelling can cause pain behind the eye or pain with eye movement, as well as decreased color perception or sudden vision loss. 

Optic neuritis can occur with multiple sclerosis, mumps, measles, Lyme disease, lupus, sarcoidosis, cat scratch disease, syphilis or herpes. 

What to do: You should consult an ophthalmologist to identify the underlying cause. Treatment depends on the condition triggering the eye inflammation. 

12. Scleritis

Scleritis is an inflammation that occurs within the sclera, which is the external lining of the eyeball. This inflammation can lead to pain behind the eyes, redness and light sensitivity. 

Some causes of scleritis include rheumatoid arthritis, lupus, Sjogren's syndrome, scleroderma, Wegener’s disease or inflammatory bowel diseases. Scleritis can also emerge as a result of eye surgery ,accidents, a foreign body in the eye or an eye infection. 

What to do: The underlying cause of the scleritis should first be identified, as this will guide the ophthalmologist’s treatment approach. The doctor may prescribe antibiotics or immunosuppressants.  

13. Burn

A burn in the eye can occur due to UV ray exposure, photography flashes, tanning beds and welding without PPE. These activities can burn or injure the cornea, leading to intense pain, tearing and the sensation of a foreign body in the eye. 

What to do: Treatment should be prescribed by a doctor, which may involve antibiotic eye or ointments, anesthetic eye drops or anti-inflammatory medications for pain relief.