Dry Eye Disease (Keratoconjunctivitis Sicca)
Causes, artificial tears, and managing ocular surface disease
Dry eye disease (also called keratoconjunctivitis sicca, or KCS) is one of the most common eye conditions, affecting an estimated 10–15% of the adult population. It occurs when the eyes do not produce enough tears, or when tears evaporate too quickly, leading to ocular surface inflammation and symptoms of discomfort. Despite its name, dry eye can paradoxically cause watery eyes — the reflex tearing triggered by ocular surface irritation. Careful evaluation of the type and severity of dry eye guides selection of the appropriate lubricant and any additional treatment.
What Causes Dry Eye?
Dry eye is classified into two main types: aqueous-deficient dry eye, where the lacrimal glands produce insufficient tears, and evaporative dry eye, where tears evaporate too quickly due to meibomian gland dysfunction (MGD) — a blockage of the oil-secreting glands along the eyelid margin. MGD is now recognised as the most common cause of dry eye. Risk factors include increasing age, female sex (hormonal changes), contact lens wear, prolonged screen use (reduces blink rate), low humidity or air conditioning environments, certain medications (antihistamines, diuretics, antidepressants, beta-blockers, isotretinoin), systemic conditions (Sjögren's syndrome, rheumatoid arthritis, lupus, thyroid disease, diabetes), and previous refractive eye surgery.
Symptoms and Diagnosis
Typical symptoms include a persistent feeling of grittiness or a foreign body in the eye, burning, stinging, or soreness, redness, sensitivity to light, blurred vision that improves with blinking, and paradoxical watering — the eye producing excessive reflex tears in response to surface irritation. Symptoms are often worse in the afternoon or evening, in air-conditioned environments, during prolonged reading or screen use, and in windy conditions. Diagnosis is clinical, supported by tests such as the OSDI questionnaire, fluorescein staining of the cornea, rose bengal or lissamine green staining of the conjunctiva, Schirmer's test (tear production measurement), and tear break-up time (TBUT) to assess tear stability.
Treatment
Treatment is stepped according to severity. Mild dry eye is managed with lubricant eye drops (artificial tears). Sodium hyaluronate (hyaluronic acid) drops are well tolerated and widely used. For moderate-severe or persistent symptoms, preservative-free formulations are preferred, particularly if used more than four times daily or with contact lenses. Gel preparations (carbomer gel, Viscotears) and ointments (Simple Eye Ointment) provide longer contact time and are useful for overnight use. Lipid-based drops (Systane Complete, Cationorm) specifically address the evaporative component in MGD. Lid hygiene (warm compresses, lid massage, lid wipes) is essential for meibomian gland dysfunction. Omega-3 fatty acid supplements may improve meibomian gland function. Ciclosporin 0.1% eye drops (Ikervis) are licensed for severe dry eye with corneal inflammation. Punctal plugs can be inserted to block tear drainage and increase tear retention. This article has been prepared following careful evaluation of NICE CKS Dry Eye and BCLA DEWS II guidance.