Xerosis (Dry Eye Syndrome)
Dry eye disease (also called xerosis or keratoconjunctivitis sicca) is a multifactorial ocular surface disorder
marked by inadequate tear film quantity or quality 1 2 . TFOS DEWS II defines it as a loss of tear film
homeostasis with tear instability, hyperosmolarity, and ocular surface inflammation (often with
neurosensory changes) 2 . Clinically, dry eye is broadly classified into aqueous-deficient (low lacrimal
secretion, e.g. Sjögren’s syndrome) and evaporative (excess tear evaporation, often from meibomian gland
dysfunction or poor blinking) types, though many patients have a mixed picture 3 . In aqueous-deficient
dry eye, lacrimal gland dysfunction (autoimmune or age-related) reduces tear volume, whereas in
evaporative dry eye, lipid-layer insufficiency (e.g. from meibomian gland disease or eyelid abnormalities)
accelerates tear loss 3 4 .
Causes and Risk Factors
Dry eye has many causes. Major risk factors include:
• Age and sex: Prevalence increases with age (notably after 40 years)
are especially susceptible, partly due to hormonal changes.
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. Postmenopausal women
• Environmental factors: Windy, dry or air-conditioned environments and air pollutants can speed
tear evaporation. Extensive screen time or prolonged visual tasks lead to infrequent blinking and
evaporative loss 6 .
• Systemic diseases: Autoimmune disorders (Sjögren’s syndrome, rheumatoid arthritis, lupus, thyroid
disease, diabetes, etc.) often involve lacrimal gland inflammation 7 . Vitamin A deficiency
(xerophthalmia) also disrupts the ocular surface.
• Medications: Many drugs reduce tear production, including antihistamines, decongestants,
antidepressants, oral contraceptives, beta-blockers and diuretics 8 9 .
• Ocular factors: Meibomian gland dysfunction or blepharitis leads to poor lipid layer and
evaporation 4 . Contact lens wear, eyelid problems (e.g. lagophthalmos, rosacea), and prior ocular
surgery (e.g. LASIK) also increase risk.
• Lifestyle and nutrition: Low omega-3 intake and smoking may worsen dry eye. A humidified
environment and frequent breaks from screens (the “20-20-20” rule) are recommended preventive
measures 10 .
Patients may have one or more contributing factors simultaneously, and addressing modifiable causes (like
taking breaks, optimizing lid hygiene, or changing medications) is a key part of management 6 9 .
Signs and Symptoms
The hallmark symptom is ocular discomfort and vision fluctuation. Typical symptoms include burning,
stinging or gritty (“foreign body”) sensations, itching or eye pain, eye redness, and light sensitivity 11 .
Patients often report intermittent blurred or fluctuating vision, especially during reading or screen work,
which may improve briefly with blinking or using lubricating drops 11 . Paradoxically, dry eye can cause
reflex tearing or stringy mucus discharge as the eyes try to compensate 12 . These symptoms are usually
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bilateral but can vary in intensity; they often worsen later in the day or with prolonged visual tasks 11 . On
examination, findings may include conjunctival redness, punctate corneal staining (abrasions), decreased
tear meniscus, and reduced tear breakup time. Severe or chronic cases can lead to corneal epithelial
damage (filaments, ulcers) and vision loss if untreated 13 .
Pathophysiology
The tear film normally has three layers—a lipid (oil) layer from meibomian glands, an aqueous layer from
the lacrimal glands, and a mucin layer from conjunctival goblet cells—that together lubricate and protect
the cornea 14 . In dry eye, any breakdown in this tear film leads to hyperosmolarity, which is the central
abnormality in DED 2 . Tear hyperosmolarity (high salt concentration) damages ocular surface cells and
triggers inflammation. Inflammation and epithelial injury then worsen gland function in a self-perpetuating
cycle 2 . For example, meibomian gland dysfunction or eyelid laxity causes excessive evaporation and tear
film thinning 4 . Aqueous deficiency (e.g. lacrimal gland damage from Sjögren’s syndrome) causes similar
osmotic stress. Chronic inflammation may reduce goblet cell density (lower mucins) and alter corneal
nerves, further destabilizing the tear film. Thus, loss of tear-film homeostasis underlies the symptoms and
ocular surface damage seen in xerosis 2 4 .
Diagnosis and Clinical Criteria
There is no single “gold standard” test for dry eye; diagnosis relies on a combination of symptom
assessment and objective tests 15 16 . In practice, clinicians use questionnaires (e.g. OSDI, DEQ-5) to
quantify symptoms, but confirmation requires evidence of tear film instability or deficiency. Key diagnostic
tests include:
• Tear Break-Up Time (TBUT): A fluorescein dye is instilled and the time until the first dry spot
appears after a blink is measured. A break-up time <10 seconds (or non-invasive TBUT <10 s) is
considered abnormally rapid and indicative of tear instability 15 .
• Schirmer Test: Filter paper strips are placed in the lower eyelid for 5 minutes to measure tear
production. Wetting ≤10 mm after 5 min (especially ≤5 mm) signals tear deficiency 16 . (With
anesthesia, the test isolates basal tear output; without anesthesia it includes reflex tearing.) Serial
low readings strongly suggest aqueous-deficient dry eye 16 .
• Ocular Surface Staining: Fluorescein or lissamine green dyes highlight epithelial damage. Scattered
punctate staining of the cornea or conjunctiva indicates dry eye–related injury.
• Tear Osmolarity: TearLab or similar devices measure tear film salt concentration. An osmolarity
≥308 mOsm/L (or inter-eye difference >8 mOsm/L) is considered abnormal 15 .
• Additional exams: Slit-lamp evaluation of the eyelids (meibomian gland clarity), tear meniscus
height (via OCT or meniscometry), and corneal sensation may be used in specialist settings.
As TFOS DEWS II recommends, a dry eye diagnosis typically requires symptoms plus at least one positive
homeostasis test (low TBUT, high osmolarity, or significant staining) 15 . In primary care, a thorough history
(including screen use, systemic diseases, medications) guides the need for these tests or referral 17 . In
some cases (e.g. unilateral or severe pain), alternate diagnoses (allergic conjunctivitis, infection) must be
excluded before labeling dry eye.
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Treatment
Treatment is stepwise, ranging from simple lifestyle measures to advanced therapies, depending on
severity:
• Environmental and behavioral: Take regular breaks during screen use (the “20-20-20” rule), ensure
proper blinking, and increase ambient humidity 6 10 . Protect eyes from wind or air conditioning.
Adjust medications that may worsen dryness, if possible.
• Lubrication: Frequent use of preservative-free artificial tears or gels is first-line 18 . Lipidcontaining or gel formulations may benefit evaporative dry eye. Ointments at bedtime prevent
nocturnal dryness.
• Eyelid hygiene: Warm compresses and lid cleansing (e.g. tea-tree or hypochlorous acid cleansers)
treat coexisting blepharitis/ meibomian gland dysfunction 19 20 , improving the lipid layer.
• Topical anti-inflammatories: When symptoms persist, prescription drops are used. Cyclosporine
A ophthalmic emulsion (e.g. Restasis) and lifitegrast (Xiidra) inhibit ocular surface inflammation and
help restore tear production 21 22 . Short courses of topical steroids (in the eye) may be used for
acute flares, but long-term steroid use is avoided due to side effects.
• Autologous blood-derived tears: In severe cases, specially processed autologous serum eye
drops (made from the patient’s own blood) provide growth factors and vitamins that promote
healing 23 . Platelet-rich plasma and similar biologic tear substitutes are also explored in advanced
dry eye management.
• Tear-conserving measures: Punctal plugs or cautery temporarily or permanently occlude the
lacrimal puncta to slow tear drainage 24 . This is often used for moderate-to-severe dry eye
refractory to drops.
• Meibomian gland therapies: Treatments targeting MGD include thermal pulsation devices (e.g.
LipiFlow) and intense pulsed light (IPL) to melt and express meibum 25 . Manual gland expression
and doxycycline (or azithromycin) may also improve gland function.
• Protective eyewear: Moisture chamber goggles or moisture-retaining spectacles can shield the eyes
in very dry environments.
• Scleral contact lenses: In advanced cases, gas-permeable scleral lenses vault over the cornea,
providing a reservoir of moisture 26 .
• Nutrition: Omega-3 fatty acids (fish oil) and antioxidants (vitamins A, C, E) may reduce inflammation
and support tear film health 27 .
• Surgery: Rarely needed, procedures such as partial tarsorrhaphy (eyelid sewing) or amniotic
membrane grafts can be performed for severe, refractory cases 28 .
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In all cases, treating underlying causes (e.g. managing Sjögren’s syndrome systemically, quitting smoking,
or adjusting environmental factors) is essential to control dry eye.
Emerging Research and Advances
New advances are rapidly shaping dry eye management:
• Anti-inflammatory and novel drug therapies: Research is ongoing into new immunomodulators
and biologics. Besides cyclosporine and lifitegrast, newer agents targeting inflammatory pathways
(e.g. cytokine blockers) are under development 29 . Cholinergic secretagogues (e.g. oral pilocarpine
or novel eye-drop agonists) to stimulate tears are also explored.
• Regenerative treatments: Blood derivatives like platelet-rich plasma and stem cell–based therapies
aim to heal the ocular surface. For example, stem cell therapy and growth factor treatments are
being investigated to regenerate lacrimal and goblet cells 30 . Autologous serum drops (containing
vitamin A, EGF, TGF-β, etc.) already provide such factors 23 .
• Advanced diagnostics: Techniques like infrared meibography, tear osmolarity measurement, and
biomarker assays improve detection of dry eye subtypes. Artificial intelligence and machine learning
are being applied to imaging and patient data for earlier, more personalized diagnosis 31 32 .
• Gene and microbiome approaches: Cutting-edge research includes gene therapy and CRISPR
editing to correct underlying genetic predispositions. Studies of the ocular surface microbiome are
also illuminating how bacterial balance affects tear film health, potentially leading to microbiometargeted therapies 33 .
• Lifestyle and device innovations: Beyond therapies, new devices (e.g. intranasal neurostimulation
to boost tear secretion) and digital tools (blink reminders, screen-filter programs) are emerging.
Nutritional and lifestyle interventions (diet, mindfulness of screen use) continue to be refined for dry
eye prevention.
These advances, many still in trials, hold promise for more effective, tailored dry eye treatments in the near
future 29 30 .
Epidemiology
Dry eye is very common worldwide, but reported rates vary widely depending on definitions and
population. TFOS DEWS II data suggest a global prevalence around 10–12% 34 . However, studies report
anywhere from ~5% to over 30% in different regions 35 36 . For example, rates as high as 42% have been
found in some African populations, ~20% in Asia, and ~8% in the United States 35 . Prevalence increases
with age (notably beyond age 40) 5 and is typically higher in women than men 37 .
Notably, dry eye is no longer limited to the elderly: increasing screen use has led to rising symptoms in
younger adults. Studies report 20–25% prevalence of dry eye symptoms in teenage and young adult
populations in parts of Asia 38 . Overall, estimates must be interpreted cautiously: criteria differ (symptom
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questionnaires vs. clinical signs), so epidemiological figures form broad ranges. Nonetheless, xerosis/dry
eye is recognized as a major public health issue affecting millions globally 34 5 .
Sources: Current clinical review articles and guidelines on dry eye disease 1 2 15 19 21
reputable health resources 39 40 , were consulted to compile this comprehensive overview.
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Overview of Dry Eye Disease for Primary Care Physicians
https://www.mdpi.com/1648-9144/61/3/460
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Dry eyes - Symptoms & causes - Mayo Clinic
https://www.mayoclinic.org/diseases-conditions/dry-eyes/symptoms-causes/syc-20371863
23 29 30 31 32 33 Exploring new Frontiers in dry eye Disease: Treatments, mechanisms, and diagnostic
innovations a comprehensive review
https://repository.unar.ac.id/jspui/bitstream/123456789/11761/1/29.pdf
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Dry Eye Syndrome - EyeWiki
https://eyewiki.org/Dry_Eye_Syndrome
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Dry Eye | National Eye Institute
https://www.nei.nih.gov/eye-health-information/eye-conditions-and-diseases/dry-eye
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