Foreign body sensation is a very common phenomenon and almost all of us have experienced this at least once in our life. You may experience this when on a windy day some dust particles are blown into your eyes or when a strand of your eyelash sometimes gets stuck in your eyes.
In each of these cases, you feel as if there is sand in your eyes, so you start to rub your eyes to get rid of the sand or dust particle or eyelash or in general any irritant that when in contact with the surface of your eyes, makes it impossible to open eyes and see properly.
It is interesting to note that this sensation is not always because of a foreign body irritating your eyes, sometimes despite the absence of an irritant you may experience this same sensation or feel like sand in your eyes. Factors that lead to this experience range from a minute irritant in the eye, which after rubbing the eyes is removed and the person feels relieved to factors in which only rubbing the eyes cannot relieve this sensation and medical intervention will be needed. Today in this article, we’ll try to understand all these causes that lead to foreign body sensations in our eyes.
what you will read next :
What does foreign body sensation feel like?
Foreign body sensation refers to the constant urge to rub and scratch the eyes as if something like a sand, dust particle or eyelash was irritating the eye. The source of this sensation is the exposed corneal nerves which are either irritated due to contact with foreign body particles such as dust and sand or are excited following a corneal injury. In later, despite the absence of any exposure to an irritant, a person may experience foreign body sensations in his or her eyes.
Cornea and its role in foreign body sensation
The cornea is the outermost, transparent, protective, dome-shaped layer of the eye covering the iris, pupil and anterior chamber of the eyes. It is a sensitive layer containing a huge number of neurons that help in the sensation of touch, pain and heat.
These neurons when elicited due to lodging of foreign body in the cornea, send impulses to the brain to order the body to perform an action that will remove this foreign body or irritant, as a result, you start to blink your eyes rapidly or rub your eyes unless the irritant is removed. Therefore, this is a protective mechanism. But sometimes due to various causes such as dry eyes in which tear film covering the eyes is faulty or decreased exposing the corneal nerves and thus with each blink these nerves are irritated causing false sensations and the person feels like there is sand in his or her eyes.
What causes foreign body sensation?
- Foreign body
This is the most obvious and first suspected cause of this sensation. As we mentioned before the presence of countless neurons make the cornea a highly sensitive layer, such that even a tiny foreign particle such as a grain of sand causes severe discomfort until and unless it is removed from the eyes. Foreign body sensation as a result of actual foreign body in the eye is sudden and transient and usually does not last long as blinking and a gentle rub is enough to get rid of the irritant.
Common foreign bodies that enter the eye and cause discomfort are sand grains, dust particles, small insects, pollens, an eyelash, sawdust, remnants of make-up and much more.
Foreign bodies entering the eyes with high speed such as metal or glass particles after an explosion or any other accident can cause serious damage to the eyes. Also, the foreign body may either be superficially present in the cornea or it may penetrate it. The latter is more serious and will require medical intervention and removal by professionals to prevent further damage and complication.
Other symptoms that may accompany the gritty sensations are red eyes, tearing and pain. In serious cases, bleeding may be present as well if the corneal layer is damaged.
This is the most obvious cause of foreign body sensation however, you may not always find a foreign body and many causes foreign body sensation despite the absence of an actual foreign body. Below we will discuss some of such causes of foreign body sensations.
- Corneal abrasion
An accidental corneal scratch due to fingernail or while applying mascara, apart from causing sudden pain, also causes foreign body sensation. In this situation the corneal epithelium or surface layer is damaged due to scratching, exposing and irritating the corneal nerves that in turn generates false impulses and the affected person feels as if something is present in his or her eyes. Other symptoms include pain, red eyes, watery eyes and blurry vision.
The damaged corneal epithelium is expected to recover without any intervention within one or two days if small. Larger abrasions may take as long as a week to recover fully.
- Corneal laceration
Sometimes the effect of a foreign body hitting the eyes may be severe enough to cause a laceration or deep cut in the corneal surface. This usually occurs as an impact of a high-speed foreign body flying into the eye. It is a serious condition and can lead to loss of vision if not treated on time. Corneal lacerations are common in occupations involving stone carving, metal grinding, woodcutting and grass trimming. Thus, it is very important to wear protective glasses when at work.
Symptoms that can be seen in the case of corneal laceration include pain, redness, excessive tearing, photophobia, bleeding eyes, inability to see properly and foreign body sensation.
When suspected, visit an ophthalmologist quickly who will make the diagnosis after the complete eye examination. Also, it is important to note that one should avoid self-removal of foreign body in this case, if still present in the eye. Also avoid taking aspirin, ibuprofen and any blood thinner as they may worsen the bleeding. Do not rub or apply any pressure on your eyes.
Surgical closure of the cut is the treatment for a corneal laceration.
- Corneal ulcer or keratitis
A corneal ulcer is an open wound of the cornea associated with severe inflammation. It often results from an infection due to any microorganism such as bacteria, virus, fungi or parasite. Severe dry eyes and recurrent corneal abrasions can also cause ulcers.
Corneal ulcers following a bacterial infection are common in people who use contact lenses, especially extended-wear lenses.
Common viruses that can cause keratitis include the herpes simplex virus (HSV, common agent of cold sores) and varicella-zoster virus(VZV, causative agent of chickenpox and shingles). Viral infections can be triggered by stress, a weak immune system and even sun exposure.
Symptoms include painful and sore eyes, redness, tearing affected eye, pus discharge, blurred vision, white spots on the cornea, turbid cornea impairing the vision, photophobia or sensitivity to light and feeling that something is in the eye.
Corneal ulcers are serious medical conditions requiring proper assessment and treatment in absence of which, permanent damage of the eyes can occur, resulting in blindness.
Diagnosis is made by complete eye examination by an ophthalmologist using a slit lamp and fluorescein dye. Once diagnosed, antimicrobial eye drops are prescribed as treatment. Corneal ulcers may heal while leaving a scar. This scar can disrupt normal vision for which a corneal transplant surgery will be required.
- Dry eyes syndrome
In modern times where technological devices have become common household objects, the prevalence of dry eyes has also increased. Dry eyes syndrome refers to the inability of the tear layer of the eye to lubricate, nourish and thus protect the eye. Tears play an important role in protecting the eyes from drying up which can cause erosion and ulcers if severe. When we blink our eyes, tears spread across our eyes, forming a protective covering and layer. The components of tears also have antimicrobial properties and thus protect the eyes from infections.
Tears also wash away any foreign body that causes discomfort. Now, when due to any reason these tear layer is either deficient or faulty in its functionality because of poor quality tears, dry eyes syndrome occurs.
Symptoms of dry eyes are redness, itching, gritty eyes and feeling of sand in the eyes, fatigue and irritation.
Treatment for mild cases of dry eyes includes over-the-counter artificial tears.
Staying hydrated and regular blinking when working on a computer or studying can be done to prevent the eyes from drying.
- Blepharitis
Blepharitis is the inflammation of the eyelid. People with blepharitis often complaint about foreign body sensations. Other symptoms present includes crusting at the base of eyelashes, swollen and red eyelids, itching and burning sensation, blurry vision and excessive tearing.
Too much oil production and growth of bacteria are possible causes of ulcerative blepharitis. Non-ulcerative blepharitis occurs in allergies such as hay fever. Both ulcerative and non ulcerative blepharitis are acute forms of blepharitis.
Treatment includes proper eyelid hygiene techniques and using warm compressions to reduce inflammation.
Antimicrobial eye drops can also be prescribed for a duration of 2 to 8 weeks.
- Conjunctivitis or pink eye
Although most of the foreign body sensations arise from exposed or irritated corneal nerves, inflamed conjunctiva can also cause a sensation of foreign body in the eyes.
Conjunctiva is a clear, transparent outer layer of eye which covers the white sclera and inner layer of eyelids. Allergies or viral infections are some of the common causes of conjunctivitis. The symptoms associated with conjunctivitis are red eyes, increased tearing of the affected eye, pain and irritation, itching, gritty sensation, watery or sticky discharge and also swollen eyelids. Conjunctivitis caused by bacteria and virus is very contagious.
Recovery is spontaneous within 1 or 2 week. Treatment will be needed if it extends beyond 2 weeks.
- Stye or hordeolum
Stye refers to a small, painful, red bump at the base of eyelid caused mostly due to a bacterial infection of the eyelash root or oil glands in eyelid. It is common at the edge of eyelids and is extremely painful. In the beginning, it presents as tender and red eyelids with of without itching. Other symptoms include small, painful bump with a pustular centre, crusty eyelid, foreign body sensation as a result of mechanical friction caused by stye and excessive tearing.
Warm compressions are used for treating a stye. You should not pop up the stye as it can spread the infection. Sometimes surgical drainage of the stye may be needed if it does not heal up itself and is impairing the vision.
Emergency
It is important to take the eye injury seriously and visit a medical professional as quick as possible specially in the following conditions:
If a foreign body flies into the eye at a high speed
If the foreign body hitting the eye is sharp, or large or contains chemicals
If the foreign body is stuck in or penetrates the eye
If eyes start to bleed
Also, if the foreign body sensation is present even in absence of an actual foreign body, you should visit the doctor for proper evaluation of the cause.
Vision is nature’s blessing to us and we must value this blessing by taking proper care of our eyes. A little negligence and carelessness can result in loss of vision and thus a life of complete darkness where the affected person won’t be able to see the beauty of the world around him or her. Regular eye check-ups, healthy diet, exercise and consulting the professionals when faced with a problem, are few steps that you can take to value this beautiful gift of nature and enjoy the beauty surrounding you.