Eye pain causes: When is eye pain an emergency?
Eye pain is a catch-all phrase to describe discomfort on, in, behind or around the eye.
The pain can be unilateral or bilateral — in other words, you can experience right eye pain, left eye pain, or the discomfort can affect both eyes. There's no evidence that right eye pain occurs more frequently than left eye pain, or vice versa.
In some cases, such as an eye injury, the cause of the pain is obvious. But often it's difficult to know why your eye hurts.
To complicate matters, the severity of eye pain does not indicate how serious the underlying cause of the discomfort is. In other words, a relatively minor problem, such as a superficial abrasion of the cornea, can be very painful.
A painful eye can produce various sensations and accompanying symptoms, which can help your optician determine the cause of your discomfort and prescribe the correct eye pain treatment. These include:
A sharp, stabbing sensation
A dull ache
Feeling something is "in" your eye (foreign body sensation)
Causes of eye pain
Here are common causes of eye pain, based on the location of the discomfort.
Pain on or in your eye
Often, eye pain that feels like something is in the eye actually is caused by irritation or inflammation of the front surface of the eye, particularly the cornea.
Common causes of pain emanating from the front surface of the eye or inside the eye include:
Corneal foreign body
Not surprisingly, what often causes a foreign body sensation in the eye is an actual foreign body. Common foreign bodies that can adhere to and become embedded in the surface of the cornea include metal shavings, inorganic grit (sand, tiny stone particles), sawdust and other organic material.
The discomfort from a corneal foreign body can range from mild to severe, and typically it is most bothersome when you're blinking (since the eyelid often is rubbing across it during blinks). Blurred vision and sensitivity to light also are common.
A corneal foreign body requires urgent attention from an optician, because material embedded in the cornea can quickly cause a serious eye infection.
Most corneal foreign bodies can be removed easily in the opticians practice with the proper tools. Antibacterial eye drops may be prescribed to prevent infection while the cornea heals.
This is a scratched cornea. Although most corneal abrasions are not serious, they can be very uncomfortable and cause light sensitivity and watery eyes.
Many superficial corneal scratches heal on their own within 24 hours. But deeper abrasions can lead to a serious eye infection and even a corneal ulcer if left untreated.
Because it's often impossible to tell if eye pain is due to a minor scratch, a deep abrasion or a corneal foreign body, it's a good idea to see an optician for any sharp discomfort of the eye that does not resolve very quickly, to determine the underlying cause.
Another very common cause of eye discomfort is dry eyes. Usually dry eye discomfort begins more slowly and gradually than eye pain from a corneal foreign body or abrasion. Sometimes dry eyes can lead to a corneal abrasion, because there are not enough tears on the surface of the eye to keep the cornea moist and slippery.
If using lubricating eye drops significantly improves comfort, the cause of the pain is probably dry eyes. In most cases, dry eye does not require urgent attention; but your optician can perform tests to determine the severity of the dryness and recommend the most effective treatment.
Other (less common) causes of anterior eye pain, or pain "in" the eye, include:
Eye infections (including fungal eye infections and Acanthamoeba keratitis)
Iritis (anterior uveitis), which is inflammation of the iris
Contact lens discomfort
A very serious cause of pain in the eye is a condition called endophthalmitis, which is inflammation of the interior of the eye that most often is caused by a bacterial infection. It also can occur as a rare complication of cataract surgery.
Endophthalmitis, in addition to causing eye pain, causes redness, swollen eyelids and decreased vision. If you have these symptoms after cataract surgery or other eye surgery, see your optician immediately.
Stabbing pain in the eye
Common causes of pain behind the eyes are migraine headaches and sinus infections.
In the case of a migraine headache, the pain almost always is behind only one eye and often is accompanied by pain elsewhere on the same side of the head.
Pain behind the eye from a sinus infection usually is less severe than pain from a migraine, and both eyes may be affected.
Though pain behind the eyes from these causes typically is not an emergency, if you have chronic or recurring pain of this type, see your optician or GP for treatment and to see what can be done to prevent future episodes.
Pain in the eye socket
Probably the most common pain around the eyes is inflammation within the eyelid, which is the common stye (or hordeolum). The primary symptom of a stye is a localised, very tender area on one eyelid.
A stye does not require urgent attention from an optician and usually can be successfully treated at home by applying warm compresses to the eyelid several times a day for a few days. SEE RELATED: How to get rid of a stye
Blepharitis is another common (and usually not urgent) problem that can cause swollen eyelids and discomfort around the eyes.
Another common cause of pain around the eyes and eye muscle pain is overuse of the eyes when working at the computer. This is not an urgent problem, and there are simple steps you can take to relieve computer eye strain.
A much less common and much more serious cause of pain around the eyes is a condition called optic neuropathy, which can cause permanent vision loss. Accompanying symptoms are usually decreased visual acuity and reduced colour vision, and the pain typically is worse with eye movements.
Eye pain that may be caused by optic neuropathy requires immediate attention by an ophthalmologist and a neurologist. Among people under 40, multiple sclerosis and other neurological conditions are the most common causes of optic neuritis.
Eye pain treatment
You should consider any eye pain an emergency. Almost always, the right eye pain treatment is to immediately schedule an eye exam with an optician near you. Only an eye care professional can determine the exact cause of your eye pain and prescribe the correct treatment to prevent damage to the eye and possibly permanent vision loss.
In particular, see your optician immediately if you have a painful eye and:
The pain occurred immediately after grinding metal, sawing wood, or other activities that might cause a foreign body injury (especially if you were not wearing safety glasses or protective eyewear).
The pain is due to an eye injury.
The pain is severe and is accompanied by blurred vision and/or sensitivity to light.
You have had recent eye surgery, including LASIK and cataract surgery.
You have redness and discharge from the eye.
The pain is severe, came on suddenly, and you have a history of glaucoma. This could signal an acute attack of a less common form of glaucoma called angle-closure glaucoma, which can cause rapid vision loss and is a medical emergency.
When it comes to eye pain, don't take chances — see an optician as soon as possible to determine the exact cause of the pain and receive the right eye pain treatment.
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Page published in June 2019
Page updated in March 2022