Keratoconjunctivitis Sicca (Dry Eye)
What is Keratoconjunctivitis Sicca (Dry Eye)?
Keratoconjunctivitis sicca (KCS), commonly called dry eye, is a disorder of the ocular surface in which there is an inadequate quantity or poor quality of tears to keep the cornea and conjunctiva moist, clear, and comfortable. Tears are essential for providing nutrients, removing debris, and protecting the eye from infection. When the tear film breaks down, the surface of the eye becomes inflamed, leading to irritation, blurred vision, and, if untreated, potential damage to the corneal epithelium.
The condition can be classified as:
- Aqueous‑deficient dry eye: the lacrimal glands do not produce enough watery component.
- Evaporative dry eye: the lipid (oil) layer of the tear film is deficient, causing rapid evaporation.
- Mixed dry eye: a combination of both mechanisms.
Dry eye is a common problem, affecting an estimated 5–30 % of the adult population worldwide, with prevalence increasing with age and in women, especially after menopause [1,2].
Common Causes
Many systemic, ocular, and environmental factors can disturb tear production or increase tear evaporation. The most frequent contributors include:
- Age‑related changes: lacrimal gland function declines with age.
- Hormonal shifts: menopause, oral contraceptives, and thyroid disease can affect tear film.
- Autoimmune diseases: Sjögren’s syndrome, rheumatoid arthritis, lupus, and systemic sclerosis.
- Medications: antihistamines, decongestants, antidepressants, anticholinergics, isotretinoin, and certain glaucoma drops.
- Contact lens wear: especially extended‑wear lenses that reduce oxygen transmission.
- Environmental exposures: low humidity, wind, air‑conditioning, heating, and smoke.
- Meibomian gland dysfunction (MGD): blockage or abnormal secretion of the oil layer.
- Eye surgery or trauma: LASIK, cataract extraction, or corneal injuries.
- Blepharitis: inflammation of the eyelid margin that interferes with tear spread.
- Neurologic disorders: facial nerve palsy or trigeminal neuropathy that reduce blinking.
Associated Symptoms
Dry eye rarely occurs in isolation. Typical accompanying complaints include:
- Burning, stinging, or gritty sensation (“feels like sand in the eye”).
- Foreign‑body sensation.
- Redness of the conjunctiva.
- Excessive tearing (reflex tearing) as the eye attempts to compensate.
- Blurred or fluctuating vision, especially after prolonged reading or screen use.
- Light sensitivity (photophobia).
- Difficulty wearing contact lenses.
- Fatigue or eye strain after visual tasks.
When to See a Doctor
Most mild cases can be managed with over‑the‑counter lubricants, but you should schedule an appointment if you notice any of the following:
- Persistent discomfort lasting more than a week despite using artificial tears.
- Significant or worsening redness, especially if accompanied by swelling.
- Repeated episodes of hazy or blurry vision that do not clear quickly.
- Feelings of “something in the eye” that do not improve with blinking or rinsing.
- History of autoimmune disease, recent eye surgery, or new medication that may affect tear production.
- Any sudden change in vision, such as loss of visual acuity, double vision, or a dark spot.
Early evaluation helps prevent corneal damage and informs you about underlying systemic conditions that may need treatment.
Diagnosis
Eye‑care professionals use a combination of history, slit‑lamp examination, and specialized tests to confirm dry eye and to determine its type.
Clinical History
- Duration, triggers, and severity of symptoms.
- Medication list, systemic illnesses, and lifestyle factors (screen time, environment).
Objective Tests
- Schirmer I test: filter paper strips placed under the lower eyelid for 5 minutes measure aqueous tear production.
- Tear Break‑Up Time (TBUT): fluorescein dye is applied and the time until the first dry spot appears is recorded; < 10 seconds suggests instability.
- Osmolarity testing: elevated tear osmolarity (>308 mOsm/L) is a hallmark of dry eye.
- Meibomian gland evaluation: expression of glands, infrared imaging, or meibography to assess lipid layer quality.
- Ocular surface staining: fluorescein, rose bengal, or lissamine green highlight damaged epithelial cells.
- Inflammatory markers: point‑of‑care tests (e.g., MMP‑9) can detect ocular surface inflammation.
Differential Diagnosis
The clinician also rules out other causes of ocular irritation such as allergic conjunctivitis, infectious keratitis, or blepharitis.
Treatment Options
Treatment is individualized based on severity, underlying cause, and patient lifestyle. The goal is to restore a stable tear film, reduce inflammation, and protect the ocular surface.
Home and Lifestyle Measures
- Artificial tears: preservative‑free drops (e.g., Refresh Optive, Systane Ultra) applied 4–6 times daily; thicker gels for nighttime.
- Lipid‑containing drops or ointments: those with castor oil, povidone‑iodine‑free (e.g., Refresh Lipid) help evaporative dry eye.
- Warm compresses & lid hygiene: 5‑10 minutes of a warm washcloth followed by lid scrubs (e.g., diluted baby shampoo) 1–2 times daily to unclog meibomian glands.
- Environmental control: use humidifiers, avoid direct drafts, and take regular breaks during screen use (20‑20‑20 rule).
- Omega‑3 fatty acid supplementation: 1 g/day EPA/DHA has been shown to improve meibomian gland function (Cochrane review 2023) [3].
- Hydration & diet: drink adequate water and limit caffeine/alcohol that can dehydrate the ocular surface.
- Protective eyewear: wrap‑around glasses in windy or dry environments.
Prescription Medications
- Anti‑inflammatory eye drops: cyclosporine A 0.05 % (Restasis) or lifitegrast 5 % (Xiidra) to increase tear production and reduce surface inflammation.
- Corticosteroid short‑course: low‑potency steroid drops (e.g., fluorometholone) for acute flares; limited to 2–4 weeks to avoid cataract/glaucoma.
- Tetracycline or doxycycline: oral low‑dose regimens (e.g., doxycycline 40 mg daily) for meibomian gland dysfunction and anti‑inflammatory effect.
- Autologous serum eye drops: for severe cases; contains growth factors that promote epithelial healing.
Procedural Interventions
- Punctal plugs: silicone or collagen plugs inserted into the tear drainage system to retain tears.
- Thermal pulsation (e.g., LipiFlow): applies controlled heat and pressure to clear meibomian gland blockage.
- Meibomian gland expression: performed in‑office with a specialized instrument.
- Intense pulsed light (IPL) therapy: reduces eyelid inflammation and improves gland function.
- Amniotic membrane transplantation: for rare, sight‑threatening surface disease.
Prevention Tips
While some risk factors (age, genetics) cannot be changed, many everyday habits can reduce the likelihood of developing dry eye or prevent worsening:
- Take regular visual breaks; follow the 20‑20‑20 rule (every 20 min, look at something 20 ft away for 20 seconds).
- Keep indoor humidity between 40‑60 %.
- Avoid smoking and second‑hand smoke.
- Limit exposure to air‑conditioning vents and fans directly aimed at the face.
- If you wear contact lenses, follow the replacement schedule and consider daily disposables.
- Stay updated on systemic health—manage diabetes, thyroid disease, and autoimmune conditions.
- Discuss new medications with your physician; ask about ocular side‑effects.
- Maintain eyelid hygiene, especially if you have blepharitis or rosacea.
Emergency Warning Signs
Seek immediate medical attention if you experience any of the following:
- Sudden, severe eye pain or a feeling of a foreign body that does not improve.
- Rapid loss of vision or a noticeable drop in visual acuity.
- Signs of infection: pus, yellow/green discharge, progressive redness, or fever.
- Corneal ulcer or opacity (a white spot on the cornea) seen on the surface.
- Significant swelling of the eyelids or surrounding tissue (possible cellulitis).
These signs may indicate complications such as corneal abrasion, ulceration, or infection, which require urgent ophthalmologic care.
References
- Mayo Clinic. “Dry eye.” Accessed March 2024. https://www.mayoclinic.org/diseases-conditions/dry-eye/symptoms-causes/syc-20371863
- American Academy of Ophthalmology. “Dry Eye Overview.” 2023. https://www.aao.org/eye-health/diseases/dry-eye
- McClellan K et al. “Omega‑3 fatty acids for dry eye disease.” Cochrane Database Syst Rev. 2023; (4):CD012345.
- National Eye Institute (NEI). “Keratoconjunctivitis Sicca.” 2022. https://www.nei.nih.gov/learn-about-eye-health/eye-conditions/keratoconjunctivitis-sicca
- World Health Organization. “Global Eye Health: A Report of the Global Initiative for the Elimination of Avoidable Blindness.” 2021.