Dry eye syndrome, also known as keratoconjunctivitis sicca, is the condition of having dry

eyes An eye is a sensory organ that allows an organism to perceive visual information. It detects light and converts it into electro-chemical impulses in neurons (neurones). It is part of an organism's visual system. In higher organisms, the ey ...

. Symptoms include dryness in the eye, irritation, redness, discharge, blurred vision, and easily fatigued eyes. Symptoms range from mild and occasional to severe and continuous. Dry eye syndrome can lead to blurred vision, instability of the tear film, increased risk of damage to the ocular surface such as scarring of the cornea, and changes in the eye including the neurosensory system. Dry eye occurs when either the eye does not produce enough

tears Tears are a clear liquid secreted by the lacrimal glands (tear gland) found in the eyes of all land mammals. Tears are made up of water, electrolytes, proteins, lipids, and mucins that form layers on the surface of eyes. The different types of ...

or when the tears evaporate too quickly. This can be caused by age,

contact lens Contact lenses, or simply contacts, are thin lenses placed directly on the surface of the eyes. Contact lenses are ocular prosthetic devices used by over 150 million people worldwide, and they can be worn to correct vision or for cosmetic ...

use,

meibomian gland dysfunction Meibomian gland dysfunction (MGD, also meibomitis or meibomianitis) is a chronic disease of the meibomian glands, which is commonly characterized by obstruction of the end of the duct that delivers the secretion produced by the glands (called m ...

pregnancy Pregnancy is the time during which one or more offspring gestation, gestates inside a woman's uterus. A multiple birth, multiple pregnancy involves more than one offspring, such as with twins. Conception (biology), Conception usually occurs ...

, Sjögren syndrome,

vitamin A deficiency Vitamin A deficiency (VAD) or hypovitaminosis A is a lack of vitamin A in blood and tissues. It is common in poorer countries, especially among children and women of reproductive age, but is rarely seen in more developed countries. Vitamin A pla ...

, omega-3 fatty acid deficiency, LASIK surgery, and certain medications such as

antihistamine Antihistamines are drugs which treat allergic rhinitis, common cold, influenza, and other allergies. Typically, people take antihistamines as an inexpensive, generic (not patented) drug that can be bought without a prescription and provides ...

s, some blood pressure medication,

hormone replacement therapy Hormone replacement therapy (HRT), also known as menopausal hormone therapy or postmenopausal hormone therapy, is a form of hormone therapy used to treat symptoms associated with female menopause. Effects of menopause can include symptoms such ...

, and

antidepressants Antidepressants are a class of medications used to treat major depressive disorder, anxiety disorders, chronic pain, and addiction. Common side effects of antidepressants include dry mouth, weight gain, dizziness, headaches, akathisia, sexu ...

. Chronic

conjunctivitis Conjunctivitis, also known as pink eye or Madras eye, is inflammation of the conjunctiva, the thin, clear layer that covers the white surface of the eye and the inner eyelid. It makes the eye appear pink or reddish. Pain, burning, scratchiness ...

such as from tobacco smoke exposure or infection may also lead to the condition. Diagnosis is mostly based on the symptoms, though several other tests may be used. Dry eye syndrome occasionally makes wearing contact lenses impossible. Treatment depends on the underlying cause. Artificial tears are usually the first line of treatment. Wrap-around glasses that fit close to the face may decrease tear evaporation. Looking carefully at the medications a person is taking and, if safe, altering the medications, may also improve symptoms if these medications are the cause. Some topical medications, or

eye drop Eye drops or eyedrops are liquid drops applied directly to the surface of the eye usually in small amounts such as a single drop or a few drops. Eye drops usually contain saline to match the salinity of the eye. Drops containing only saline ...

s, may be suggested to help treat the condition. The immunosuppressant cyclosporine (ciclosporin) may be recommended to increase tear production and, for short-term use, topical

corticosteroid Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are invo ...

medications are also sometimes helpful to reduce inflammation. Another treatment that is sometimes suggested is lacrimal plugs that prevent tears from draining from the surface of the eye. Dry eye syndrome is a common

eye disease This is a partial list of human eye diseases and disorders. The World Health Organization (WHO) publishes a classification of known diseases and injuries, the International Statistical Classification of Diseases and Related Health Problems, or ...

. It affects 5–34% of people to some degree depending on the population looked at. Among older people it affects up to 70%. In China it affects about 17% of people. The phrase "keratoconjunctivitis sicca" means "dryness of the cornea and

conjunctiva In the anatomy of the eye, the conjunctiva (: conjunctivae) is a thin mucous membrane that lines the inside of the eyelids and covers the sclera (the white of the eye). It is composed of non-keratinized, stratified squamous epithelium with gobl ...

" in

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

Signs and symptoms

Typical symptoms of dry eye syndrome are dryness, burning and a sandy-gritty eye irritation that gets worse as the day goes on. Symptoms may also be described as itchy, stinging or tired eyes. Other symptoms are pain, redness, a pulling sensation, and pressure behind the eye. There may be a feeling that something, such as a speck of dirt, is in the eye. The resultant damage to the eye's surface increases discomfort and sensitivity to bright light. Both eyes usually are affected. There may also be a stringy discharge from the eyes. Although it may seem contradictory, dry eye can cause the eyes to water due to irritation. One may experience excessive tearing such as if something got into the eye. These reflex tears will not necessarily make the eyes feel better since they are the watery tears that are produced in response to injury, irritation, or emotion which lack the lubricating qualities necessary to prevent dry eye. Because blinking coats the eye with tears, symptoms are worsened by activities in which the rate of blinking is reduced due to prolonged use of the eyes. These activities include prolonged reading, computer usage ( computer vision syndrome), driving, or watching television. Symptoms increase in windy, dusty, or smoky (including cigarette smoke) areas, in dry environments with high altitudes including airplanes, on days with low humidity, and in areas where an air conditioner (especially in a car), fan, heater, or even a hair dryer is being used. Symptoms reduce during cool, rainy, or foggy weather and in humid places, such as in the shower. Most people who have dry eyes experience mild irritation with no long-term effects. However, if the condition is left untreated or becomes severe, it can produce complications that can cause eye damage, instability of the tear film, neurosensory changes, impaired vision, or (rarely) in the loss of vision.

Causes

Any abnormality of any one of the three layers of tears produces an unstable tear film, resulting in symptoms of dry eyes.

Increased evaporation

The most common cause of dry eye is increased evaporation of the tear film, typically as a result of

(MGD). The

meibomian glands Meibomian glands (also called tarsal glands, palpebral glands, and tarsoconjunctival glands) are sebaceous glands along the rims of the eyelid inside the tarsal plate. They produce meibum, an oily substance that prevents evaporation of the ey ...

are two sets of oil glands that line the upper and lower eyelids and secrete the oily outer layer of the tear film—the lipid layer. These glands often become clogged due to inflammation caused by blepharitis and/or

rosacea Rosacea is a long-term skin condition that typically affects the face. It results in redness, pimples, swelling, and small and superficial dilated blood vessels. Often, the nose, cheeks, forehead, and chin are most involved. A red, en ...

, preventing an even distribution of oil. The result is an unstable lipid layer that leads to increased evaporation of the tear film. In severe cases of MGD, the meibomian glands can atrophy and cease producing oil entirely.

Low humidity

Low

humidity Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation (meteorology), precipitation, dew, or fog t ...

may cause dry eye syndrome.

Decreased tear production

Keratoconjunctivitis sicca can be caused by inadequate tear production from lacrimal hyposecretion. The aqueous tear layer is affected, resulting in aqueous tear deficiency (ATD). The

lacrimal gland The lacrimal glands are paired exocrine glands, one for each eye, found in most terrestrial vertebrates and some marine mammals, that secrete the aqueous layer of the tear film. In humans, they are situated in the upper lateral region of each o ...

does not produce sufficient tears to keep the entire conjunctiva and cornea covered by a complete layer. This usually occurs in people who are otherwise healthy. Increased age is associated with decreased tearing. This is the most common type found in postmenopausal women. In many cases, aqueous deficient dry eye may have no apparent cause (

idiopathic An idiopathic disease is any disease with an unknown cause or mechanism of apparent spontaneous origin. For some medical conditions, one or more causes are somewhat understood, but in a certain percentage of people with the condition, the cause ...

). Other causes include congenital alacrima,

xerophthalmia Xerophthalmia (from Ancient Greek () meaning "dry" and () meaning "eye") is a medical condition in which the eye fails to produce tears. It may be caused by vitamin A deficiency, which is sometimes used to describe that condition, although t ...

, lacrimal gland

ablation Ablation ( – removal) is the removal or destruction of something from an object by vaporization, chipping, erosion, erosive processes, or by other means. Examples of ablative materials are described below, including spacecraft material for as ...

, and sensory denervation. In rare cases, it may be a symptom of collagen vascular diseases, including relapsing polychondritis,

rheumatoid arthritis Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects synovial joint, joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and h ...

granulomatosis with polyangiitis Granulomatosis with polyangiitis (GPA), formerly known as Wegener's granulomatosis (WG), after Nazi German physician Friedrich Wegener, is a rare, long-term, systemic disorder that involves the formation of granulomas and vasculitis, inflammatio ...

, and

systemic lupus erythematosus Lupus, formally called systemic lupus erythematosus (SLE), is an autoimmune disease in which the body's immune system mistakenly attacks healthy tissue in many parts of the body. Symptoms vary among people and may be mild to severe. Common ...

. Sjögren syndrome and other

autoimmune diseases An autoimmune disease is a condition that results from an anomalous response of the adaptive immune system, wherein it mistakenly targets and attacks healthy, functioning parts of the body as if they were foreign organisms. It is estimated that ...

are associated with aqueous tear deficiency. Drugs such as

isotretinoin Isotretinoin, also known as 13-''cis''-retinoic acid and sold under the brand name Accutane among others, is a medication used to treat skin diseases like harlequin-type ichthyosis, and lamellar ichthyosis, and severe cystic acne or moderat ...

, sedatives, diuretics, tricyclic

antihypertensive Antihypertensives are a class of drugs that are used to treat hypertension (high blood pressure). Antihypertensive therapy seeks to prevent the complications of high blood pressure, such as stroke, heart failure, kidney failure and myocardial infa ...

s, oral contraceptives, antihistamines, nasal decongestants, beta-blockers, phenothiazines, atropine, and pain relieving opiates such as morphine can cause or worsen this condition. Infiltration of the lacrimal glands by

sarcoidosis Sarcoidosis (; also known as Besnier–Boeck–Schaumann disease) is a disease involving abnormal collections of White blood cell, inflammatory cells that form lumps known as granulomata. The disease usually begins in the lungs, skin, or lymph n ...

or tumors, or post-radiation fibrosis of the lacrimal glands can also cause this condition. Recent attention has been paid to the composition of tears in normal or dry-eye individuals. Only a small fraction of the estimated 1543 proteins in tears are differentially deficient or upregulated in dry eye, one of which is

lacritin Lacritin is a 12.3 kDa glycoprotein encoded in humans by the ''LACRT'' gene. Lacritin's discovery emerged from a screen for factors that stimulate tear protein secretion. Lacritin is a secreted protein found in tears and saliva. Lacritin als ...

. Topical lacritin promotes tearing in rabbit preclinical studies. Also, topical treatment of eyes of dry eye mice (Aire knockout mouse model of dry eye) restored tearing, and suppressed both corneal staining and the size of inflammatory foci in lacrimal glands.

Additional causes

Excess screen time on computers, smartphones, tablets, or other digital devices can cause dry eye. "Humans normally blink about 15 times in one minute. However, studies show that we only blink about 5 to 7 times in a minute while using computers and other digital screen devices. Blinking is the eye's way of getting the moisture it needs on its surface." Aging is one of the most common causes of dry eyes because tear production decreases with age. Several classes of medications (both prescription and OTC) have been hypothesized as a major cause of dry eye, especially in the elderly. Particularly, anticholinergic medications that also cause dry mouth are believed to promote dry eye. Dry eye may also be caused by thermal or chemical burns, or (in epidemic cases) by

adenovirus Adenoviruses (members of the family ''Adenoviridae'') are medium-sized (90–100 nm), nonenveloped (without an outer lipid bilayer) viruses with an icosahedral nucleocapsid containing a double-stranded DNA genome. Their name derives from t ...

es. A number of studies have found that people with

diabetes Diabetes mellitus, commonly known as diabetes, is a group of common endocrine diseases characterized by sustained high blood sugar levels. Diabetes is due to either the pancreas not producing enough of the hormone insulin, or the cells of th ...

have an increased risk for the condition. About half of all people who wear contact lenses complain of dry eyes. There are two potential connections between contact usage and dry eye. Traditionally, it was believed that soft contact lenses, which float on the tear film that covers the cornea, absorb the tears in the eyes. The connection between a loss in nerve sensitivity and tear production is also the subject of current research. Dry eye also occurs or becomes worse after LASIK and other refractive surgeries, in which the corneal nerves that stimulate tear secretion are cut during the creation of a corneal flap. Dry eye caused by these procedures usually resolves after several months, but it can be permanent. Persons who are thinking about refractive surgery should consider this. An eye injury or other problem with the eyes or

eyelid An eyelid ( ) is a thin fold of skin that covers and protects an eye. The levator palpebrae superioris muscle retracts the eyelid, exposing the cornea to the outside, giving vision. This can be either voluntarily or involuntarily. "Palpebral ...

s, such as bulging eyes or a drooping eyelid can cause keratoconjunctivitis sicca. Eyelid disorders can impair the complex blinking motion to spread tears. Abnormalities of the mucin tear layer caused by

vitamin A Vitamin A is a fat-soluble vitamin that is an essential nutrient. The term "vitamin A" encompasses a group of chemically related organic compounds that includes retinol, retinyl esters, and several provitamin (precursor) carotenoids, most not ...

deficiency,

trachoma Trachoma is an infectious disease caused by bacterium '' Chlamydia trachomatis''. The infection causes a roughening of the inner surface of the eyelids. This roughening can lead to pain in the eyes, breakdown of the outer surface or cornea ...

, diphtheric keratoconjunctivitis, mucocutaneous disorders, and certain topical medications are also causes of keratoconjunctivitis sicca. Persons with keratoconjunctivitis sicca have elevated levels of tear

nerve growth factor Nerve growth factor (NGF) is a neurotrophic factor and neuropeptide primarily involved in the regulation of growth, maintenance, proliferation, and survival of certain target neurons. It is perhaps the prototypical growth factor, in that it was ...

(NGF). The eye's surface NGF may play an important role in ocular surface inflammation associated with dry eyes.

Pathophysiology

Having dry eyes for a while can lead to tiny abrasions on the surface of the eyes. In advanced cases, the

epithelium Epithelium or epithelial tissue is a thin, continuous, protective layer of cells with little extracellular matrix. An example is the epidermis, the outermost layer of the skin. Epithelial ( mesothelial) tissues line the outer surfaces of man ...

undergoes pathologic changes, namely squamous metaplasia and loss of

goblet cell Goblet cells are simple columnar epithelial cells that secrete gel-forming mucins, like mucin 2 in the lower gastrointestinal tract, and mucin 5AC in the respiratory tract. The goblet cells mainly use the merocrine method of secretion, secre ...

s. Some severe cases result in thickening of the corneal surface, corneal erosion, punctate keratopathy, epithelial defects,

corneal ulcer Corneal ulcer, often resulting from keratitis is an inflammatory or, more seriously, infective condition of the cornea involving disruption of its epithelial layer with involvement of the corneal stroma. It is a common condition in humans part ...

ation (sterile and infected), corneal neovascularization, corneal scarring, corneal thinning, and even corneal

perforation A perforation is a small hole in a thin material or web. There is usually more than one perforation in an organized fashion, where all of the holes collectively are called a ''perforation''. The process of creating perforations is called perfor ...

. Another contributing factor may be

monomer deficiency. Lacritin monomer, the active form of lacritin, is selectively decreased in aqueous deficient dry eye, Sjögren syndrome dry eye, contact lens-related dry eye, and in blepharitis. The ocular surface

microbiome A microbiome () is the community of microorganisms that can usually be found living together in any given habitat. It was defined more precisely in 1988 by Whipps ''et al.'' as "a characteristic microbial community occupying a reasonably wel ...

, composed of a diverse community of microorganisms, has been implicated in the pathogenesis of dry eye syndrome, potentially influencing ocular surface inflammation and homeostasis.

Diagnosis

Symptom assessment is a key component of dry eye diagnosis – to the extent that many believe dry eye syndrome to be a symptom-based disease. Several questionnaires have been developed to determine a score that would allow for a diagnosis. The Ocular Surface Disease Index (OSDI) is the most frequently used questionnaire in clinical practice and research. Some tests allow patients to be classified into one of two categories, "aqueous-deficient" or "hyperevaporative". Diagnostic guidelines were published in 2007 by the Dry Eye Workshop, updated by the Dry Eye Workshop II in 2017. A

slit lamp In ophthalmology and optometry, a slit lamp is an instrument consisting of a high-intensity light source that can be focused to shine a thin sheet of light into the eye. It is used in conjunction with a biomicroscope. The lamp facilitates an ...

examination can be performed to diagnose dry eyes and to document any damage to the eye. When realizing this test, the practitioner is testing the eyelid margin. A Schirmer's test can measure the amount of moisture bathing the eye. This test is useful for determining the severity of the condition. A five-minute Schirmer's test with and without anesthesia using a Whatman #41 filter paper 5 mm wide by 35 mm long is performed. For this test, wetting under 5 mm with or without anesthesia is considered diagnostic for dry eyes. If the results for the Schirmer's test are abnormal, a Schirmer II test can be performed to measure reflex secretion. In this test, the nasal mucosa is irritated with a cotton-tipped applicator, after which tear production is measured with a Whatman #41 filter paper. For this test, wetting under 15 mm after five minutes is considered abnormal. A tear breakup time (TBUT) test measures the time it takes for tears to break up in the eye. The tear breakup time can be determined after placing a drop of

fluorescein Fluorescein is an organic compound and dye based on the xanthene tricyclic structural motif, formally belonging to Triarylmethane dye, triarylmethine dyes family. It is available as a dark orange/red powder slightly soluble in water and alcohol. ...

in the cul-de-sac. A tear protein analysis test measures the

lysozyme Lysozyme (, muramidase, ''N''-acetylmuramide glycanhydrolase; systematic name peptidoglycan ''N''-acetylmuramoylhydrolase) is an antimicrobial enzyme produced by animals that forms part of the innate immune system. It is a glycoside hydrolase ...

contained within tears. In tears, lysozyme accounts for approximately 20 to 40 percent of total protein content. A lactoferrin analysis test provides good correlation with other tests. The presence of the recently described molecule Ap4A, naturally occurring in tears, is abnormally high in different states of ocular dryness. This molecule can be quantified biochemically simply by taking a tear sample with a plain Schirmer test. Utilizing this technique it is possible to determine the concentrations of Ap4A in the tears of patients and in such a way diagnose objectively if the samples are indicative of dry eye. The tear osmolarity test has been proposed as a test for dry eye disease. Tear osmolarity may be a more sensitive method of diagnosing and grading the severity of dry eye compared to corneal and conjunctival staining, tear break-up time, Schirmer test, and meibomian gland grading. Others have recently questioned the utility of tear osmolarity in monitoring dry eye treatment.

Prevention

Avoiding refractive surgery (LASIK and PRK), limiting contact lens use, limiting computer screen use, and avoiding environmental conditions can decrease symptoms. Complications can be prevented by use of wetting and lubricating drops and ointments.

Treatment

A variety of approaches can be taken to treat dry eye syndrome. Approaches include: avoidance of exacerbating factors (things that make it worse), tear stimulation and supplementation, increasing tear retention, eyelid cleansing, and treatment of eye inflammation. Conditions such as blepharitis can often co-exist and paying particular attention to cleaning the eyelids morning and night with mild soaps and warm compresses can improve both conditions.

Avoiding exacerbating factors and environmental control

Dry eyes can be worsened by smoky environments, dust, and indoor air conditioning, and by our natural tendency to reduce our blink rate when concentrating. Purposefully blinking, especially during computer use, and resting tired eyes are basic steps that can be taken to minimise discomfort. Rubbing one's eyes can irritate them further, so should be avoided. Dry, drafty environments and those with smoke and dust should be avoided. This includes avoiding hair dryers, heaters, air conditioners, or fans, especially when these devices are directed toward the eyes. Wearing glasses or directing gaze downward, for example, by lowering computer screens can be helpful to protect the eyes when aggravating environmental factors cannot be avoided. Using a humidifier, especially in the winter, can help by adding moisture to the dry indoor air.

Tear stimulation and supplementation

For mild and moderate cases, supplemental lubrication is the most important part of treatment. Application of artificial tears is sometimes suggested every few hours and may provide temporary relief. Most artificial tear fluids contain mucoadhesive polymers such as

hyaluronic acid Hyaluronic acid (; abbreviated HA; conjugate base hyaluronate), also called hyaluronan, is an anionic, nonsulfated glycosaminoglycan distributed widely throughout connective, epithelial, and neural tissues. It is unique among glycosaminog ...

cellulose Cellulose is an organic compound with the chemical formula, formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of glycosidic bond, β(1→4) linked glucose, D-glucose units. Cellulose is an important s ...

derivatives or

polyvinyl alcohol Polyvinyl alcohol (PVOH, PVA, or PVAl) is a water- soluble synthetic polymer. It has the idealized formula H2CH(OH)sub>''n''. It is used in papermaking, textile warp sizing, as a thickener and emulsion stabilizer in polyvinyl acetate (PVAc) a ...

lubricant A lubricant (sometimes shortened to lube) is a substance that helps to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the function of transmitting forces, ...

s. These polymers remain for a prolonged period of time on the ocular surface binding high amounts of water. By the covalent attachment of thiol groups to such polymers, their ocular residence time can be even improved, as thiolated polymers (

thiomer Thiolated polymers designated thiomers are functional polymers used in biotechnology product development with the intention to prolong mucosal drug residence time and to enhance absorption of drugs. The name thiomer was coined by Andreas Bernkop-S ...

s) form disulfide bonds with cysteine-rich subdomains of

mucus Mucus (, ) is a slippery aqueous secretion produced by, and covering, mucous membranes. It is typically produced from cells found in mucous glands, although it may also originate from mixed glands, which contain both Serous fluid, serous and muc ...

glycoproteins on the ocular surface. Chitosan-N-acetylcysteine containing eye drops showed a significant reduction in symptoms of dry eye syndrome. There are many different types of artificial tear on the market, however, there is no strong evidence to suggest that certain artificial tear formulations are superior to others in treating dry eye.

Autologous serum eye drops

Eye drops that include autologous serum (serum taken from the same person's blood and used in an eye drop formulation) are sometimes suggested to help supplement natural tears. The composition of serum has similarities to natural tears and may mimic natural tears. Evidence supporting this approach shows that autologous serum may be superior to artificial tears at relieving symptoms in the short-term, however, there is no strong evidence that autologous serum eye drops are better than artificial tears or saline solution for long-term symptom relief.

Additional options

Lubricating tear ointments can be used during the day, but they generally are used at bedtime due to poor vision after application. They contain white petrolatum,

mineral oil Mineral oil is any of various colorless, odorless, light mixtures of higher alkanes from a mineral source, particularly a distillate of petroleum, as distinct from usually edible vegetable oils. The name 'mineral oil' by itself is imprecise, ...

, and similar lubricants. They serve as a lubricant and an emollient. Application requires pulling down the lower eyelid and applying a small amount (0.25 in) inside. Depending on the severity of the condition, it may be applied from every hour to just at bedtime. It should never be used with contact lenses. Specially designed glasses that form a moisture chamber around the eye may be used to create additional humidity.

Medication

Inflammation occurring in response to tears film hypertonicity can be suppressed by mild topical

s or with topical immunosuppressants such as

ciclosporin Ciclosporin, also spelled cyclosporine and cyclosporin, is a calcineurin inhibitor, used as an immunosuppressant medication. It is taken Oral administration, orally or intravenously for rheumatoid arthritis, psoriasis, Crohn's disease, nephr ...

(Restasis, Vevye). Elevated levels of tear NGF can be decreased with 0.1%

prednisolone Prednisolone is a corticosteroid, a steroid hormone used to treat certain types of allergies, inflammation, inflammatory conditions, autoimmune disorders, and cancers, Electrolyte imbalance, electrolyte imbalances and skin conditions. Some of ...

Topical corticosteroids

Topical corticosteroids are commonly prescribed for those whose dry eye syndrome symptoms may be caused by inflammation and may lead to a small to moderate improvement in dry-eye symptoms when compared to lubricants or artificial tear drop treatment alone. It is not clear if topical corticosteroid treatment leads to an improvement in the quality of the tear film or the quantity of natural tears. There are also risks to consider with long-term use of topical corticosteroid treatment including an increased risk of ocular hypertension, risk of cataract development, and increased risk of eye infections. For people who may benefit from topical corticosteroid treatment for dry eye syndrome, the ideal treatment regime, formulation of the topical preparations, and balance between potential risks of this medication is unclear.

Ciclosporin (cyclosporin)

Topical

(topical ciclosporin A, tCSA) 0.05% ophthalmic emulsion is an immunosuppressant that is commonly used to treat symptoms of dry eye syndrome. The drug decreases surface inflammation to increase tear production. Some people find relief and report increased tear production, however, evidence of effectiveness from clinical trials is not strong and although some people may find relief, effectiveness may be inconsistent in different people. Ciclosporin A treatment also comes with risks of adverse effects that are generally not serious but include a burning sensation. Ciclosporin should not be used while wearing contact lenses, during eye infections or in people with a history of herpes virus infections. Side effects include burning sensation (common), redness, discharge, watery eyes, eye pain, foreign body sensation, itching, stinging, and blurred vision. Long-term use of ciclosporin at high doses is associated with an increased risk of cancer. Cheaper generic alternatives are available in some countries.

Other medications

* Diquafosol, an agonist of the P2Y₂ purinergic receptor, is approved in Japan for managing dry eye disease by promoting the secretion of fluid and mucin from cells in the conjunctiva, rather than by directly stimulating the lacrimal glands. * Lifitegrast was approved by the US FDA for the treatment of the condition in 2016. * Varenicline (Tyrvaya by Oyster Point Pharma) was approved by the US FDA for the treatment of dry eye disease in October 2021. * Oral n-acetylcysteine (NAC),

and/or rebamipide-based eye drops may also be effective for dry eyes. * Perfluorohexyloctane (Miebo) was approved for medical use in the United States in May 2023.

Conserving tears

There are methods that allow both natural and artificial tears to stay longer. In each eye, there are two puncta – little openings that drain tears into the tear ducts. There are methods to partially or completely close the tear ducts. This blocks the flow of tears into the nose, and thus more tears are available to the eyes. Drainage into either one or both puncta in each eye can be blocked. Punctal plugs are inserted into the puncta to block tear drainage. It is not clear if punctal plugs are effective at reducing dry eye syndrome symptoms. Punctal plugs are thought to be "relatively safe", however, their use may result in epiphora (watery eyes), and more rarely, serious infection and swelling of the tear sac where the tears drain. They are reserved for people with moderate or severe dry eye when other medical treatment has not been adequate. If punctal plugs are effective, thermal or electric

cauterization Cauterization (or cauterisation, or cautery) is a medical practice or technique of burning a part of a body to remove or close off a part of it. It destroys some tissue in an attempt to mitigate bleeding and damage, remove an undesired growth, o ...

of puncti can be performed. In thermal cauterization, a local anesthetic is used, and then a hot wire is applied. This shrinks the drainage area tissues and causes scarring, which closes the tear duct.

Other

There is evidence that long‐chain omega‐3 supplementation may be helpful, however,

probiotic Probiotics are live microorganisms that provide health benefits when consumed, generally by improving or restoring the microbiota in the gut. Probiotics are considered generally safe to consume, but may cause bacteria– host interactions ...

s, fish- flax- and hemp-oil ( omega-3) supplements do not appear to be effective in relieving symptoms. BlephEx is a

medical device A medical device is any device intended to be used for medical purposes. Significant potential for hazards are inherent when using a device for medical purposes and thus medical devices must be proved safe and effective with reasonable assura ...

used blepharitis and dry eye disease. The handheld device is used by a doctor to exfoliate the

at the lash line and remove the inflammatory

biofilm A biofilm is a Syntrophy, syntrophic Microbial consortium, community of microorganisms in which cell (biology), cells cell adhesion, stick to each other and often also to a surface. These adherent cells become embedded within a slimy ext ...

that leads to chronic lid disease and discomfort.

Surgery

In severe cases of dry eyes, tarsorrhaphy may be performed where the eyelids are partially sewn together. This reduces the palpebral fissure (eyelid separation), ideally leading to a reduction in tear evaporation.

Prognosis

Keratoconjunctivitis sicca usually is a chronic problem. Its

prognosis Prognosis ( Greek: πρόγνωσις "fore-knowing, foreseeing"; : prognoses) is a medical term for predicting the likelihood or expected development of a disease, including whether the signs and symptoms will improve or worsen (and how quickly) ...

shows considerable variance, depending upon the severity of the condition. Most people have mild-to-moderate cases, and can be treated symptomatically with lubricants. This provides an adequate relief of symptoms. When dry eye symptoms are severe, they can interfere with quality of life. People sometimes feel their vision blurs with use, or severe irritation to the point that they have trouble keeping their eyes open or they may not be able to work or drive.

Epidemiology

Keratoconjunctivitis sicca is relatively common within the United States, especially in patients aged 40 or older. 10–20% of adults experience Keratoconjunctivitis sicca. Approximately 1 to 4 million adults (age 65–84) in the US are affected. While persons with autoimmune diseases have a high likelihood of having dry eyes, most persons with dry eyes do not have an autoimmune disease. Instances of Sjögren syndrome and keratoconjunctivitis sicca associated with it are present much more commonly in women, with a ratio of 9:1. In addition, milder forms of keratoconjunctivitis sicca also are more common in women. This is partly because hormonal changes, such as those that occur in pregnancy, menstruation, and menopause, can decrease tear production. In areas of the world where malnutrition is common, vitamin A deficiency is a common cause. This is rare in the United States. Racial predilections do not exist for this disease. A study based on 274 answers using the Ocular Surface Disease Index (OSDI) from medical school students aged between 20 and 25 years old found a prevalence of dry eye symptoms of 83.6%.

Research

New treatment options are under development. Heating systems that try to unblock the oil glands in the eye have some preliminary evidence of benefit.

Synonyms

Other names for dry eye include dry eye syndrome, keratoconjunctivitis sicca, dysfunctional tear syndrome, lacrimal keratoconjunctivitis, evaporative tear deficiency, aqueous tear deficiency, and LASIK-induced neurotrophic epitheliopathy.

Veterinary uses

Among other animals, dry eye can occur in dogs, cats, and horses.

Dogs

Keratoconjunctivitis sicca is common in dogs. Most cases are caused by a genetic predisposition, but chronic

, canine distemper, and drugs such as sulfasalazine and trimethoprim-sulfonamide also cause the disease. Symptoms include eye redness, a yellow or greenish discharge, corneal ulceration,

pigment A pigment is a powder used to add or alter color or change visual appearance. Pigments are completely or nearly solubility, insoluble and reactivity (chemistry), chemically unreactive in water or another medium; in contrast, dyes are colored sub ...

ed cornea, and blood vessels on the cornea. Diagnosis is made by measuring tear production with a Schirmer tear test. Less than 15 mm of wetting by tears produced in a minute is abnormal. Tear replacers are a mainstay of treatment, preferably containing methylcellulose or carboxymethyl cellulose. Ciclosporin stimulates tear production and acts as a suppressant on the

immune-mediated An immune disorder is a dysfunction of the immune system. These disorders can be characterized in several different ways: * By the component(s) of the immune system affected * By whether the immune system is overactive or underactive * By whether ...

processes that cause the disease. Topical

antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting pathogenic bacteria, bacterial infections, and antibiotic medications are widely used in the therapy ...

s and

s are sometimes used to treat secondary infections and inflammation. A surgery known as parotid duct transposition is used in some extreme cases where medical treatment has not helped. This redirects the duct from the parotid salivary gland to the eye.

Saliva Saliva (commonly referred as spit or drool) is an extracellular fluid produced and secreted by salivary glands in the mouth. In humans, saliva is around 99% water, plus electrolytes, mucus, white blood cells, epithelial cells (from which ...

replaces the tears. Dogs with cherry eye should have the condition corrected to help prevent this disease. Dog breeds with a higher risk of dry eye compared to other breeds include American Cocker Spaniel,

Bloodhound The bloodhound is a large scent hound, originally bred for hunting deer, wild boar, rabbits, and since the Middle Ages, for tracking people. Believed to be descended from hounds once kept at the Abbey of Saint-Hubert, Belgium, in French it is ...

, Boston Terrier, English Bulldog, Cavalier King Charles Spaniel, Lhasa Apso,

Miniature Schnauzer The Miniature Schnauzer is a dog breed, breed of small dog of the Schnauzer type that originated in Germany in the mid-to-late 19th century. Miniature Schnauzers may have been developed from the smallest specimens of the Standard Schnauzer, or c ...

, Pekingese,

Pug The Pug is a breed of dog with the physically distinctive features of a wrinkly, short-muzzled face, and curled tail. An ancient breed, with roots dating back to 400 B.C., they have a fine, glossy coat that comes in a variety of colors, most ...

, Samoyed, Shih Tzu, and West Highland White Terrier.

Cats

Keratoconjunctivitis sicca is uncommon in cats. Most cases seem to be caused by chronic conjunctivitis, especially secondary to feline herpesvirus. Diagnosis, symptoms, and treatment are similar to those for dogs.

References

External links

Facts About the Cornea and Corneal Disease
The National Eye Institute (NEI).
Dry Eye Syndrome on NHS Choices

Am.J.Managed Care - Dry Eye Disease: Pathophysiology, Classification, and Diagnosis

Dry Eye Syndrome
on

eMedicine eMedicine is an online clinical medical knowledge base founded in 1996 by doctors Scott Plantz and Jonathan Adler, and computer engineers Joanne Berezin and Jeffrey Berezin. The eMedicine website consists of approximately 6,800 medical topic revi ...

Nasolacrimal and Lacrimal Apparatus, The Merck Veterinary Manual

Guide to Treating Dry Eye Syndrome in Children
{{Authority control Syndromes in mammals Overuse injuries Syndromes affecting the eye Disorders of sclera and cornea Disorders of conjunctiva Wikipedia medicine articles ready to translate Wikipedia neurology articles ready to translate