Dry eye disease: when to treat and when to refer

Dry eye disease affects one in five adults, and can significantly impair quality of life.Most patients have mild disease.This condition is multifactorial, with an inflammatory component which can markedly worsen the impact on the ocular surface.Meibomian gland dysfunction is extremely common in dry eye disease, and contributes to the inflammatory process.Management of mild disease includes identifying and removing precipitants, and symptomatic treatment with artificial tear supplements.More advanced disease requires management of underlying ophthalmic and systemic conditions, as well as more aggressive therapies to protect the ocular surface. Dry eye disease: when to treat and when to referEvaporative Evaporative dry eye is due to a deficient tear film lipid layer, which increases tear evaporation.It is caused by meibomian gland dysfunction, which occurs in over 85% of dry eye disease.Blepharitis, or lid margin inflammation, is both a cause and an effect of meibomian gland dysfunction.The differential diagnosis of blepharitis includes ocular rosacea and atopy, seborrhoeic dermatitis, staphylococcal infection and Demodex mite infestation.Tear deficiency is thought to alter resistance to infection, so dry eye disease is both a cause and an effect of blepharitis. Risk factorsMultiple factors contribute to the development of dry eye disease (Box 1).Female gender is the most consistently identified risk factor, with the prevalence in women being almost double that in men.Advancing age is also a major risk factor, possibly due to decreased androgen levels, since androgen up-regulates meibomian gland function in animal models.While oestrogen is thought to down-regulate it, there is uncertainty as to whether hormone replacement therapy exacerbates or improves dry eye disease.3 Diagnosis and assessmentAccurately diagnosing dry eye disease and determining its severity is confounded by the variability in clinical presentation.Patients often report non-specific symptoms, such as visual disturbance, photophobia and ocular discomfort, including foreign body sensation, grittiness and burning.