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Dry%20eye%20syndrome Signs and Symptoms
Introduction
- Also known as dry eye disease (DED), keratoconjunctivitis sicca (KCS) or dysfunctional tear syndrome
- Multifactorial disease of the ocular surface characterized by a loss of tear film hemostasis associated with ocular symptoms that are secondary to several factors
Pathophysiology
- Increased osmolarity of the tear film and inflammation of the ocular surface
- Tear hyperosmolarity may be due to reduced aqueous flow or excessive evaporation of tears
- Tear film instability may be secondary to changes in function of the lipid layer, quality, quantity and availability of tear fluid
- Epithelial malfunction secondary to adverse environmental factors (eg low humidity, air conditioning or heating), ocular irritation or nerve impairment which may lead to inflammatory reactions
- Dysfunction in either of the lacrimal glands, ocular surface, eyelids, meibomian glands, or associated sensory or motor nerves which may lead to dry eye syndrome (DES) causing changes in the volume, composition, distribution, and/or clearance of the tear film
- Results in symptoms that may potentially damage the ocular surface
- Hyperosmolar tear activates release of inflammatory mediators into the tears which may eventually result in decreased sensation of the cornea, decreased reflex activity, loss of goblet cells, and reduced production of mucin
- Patients with moderate to severe DES may have reversible squamous metaplasia and punctate erosions of the ocular surface epithelium
- Severe DES may rarely cause ocular surface keratinization, microbial keratitis, corneal neovascularization, ulceration, perforation, scarring, or severe vision loss
Signs and Symptoms
- Common ocular signs and symptoms experienced by patients that usually worsen later in the day include the following:
- Blurry vision (may clear temporarily with blink)
- Burning sensation
- Contact lens intolerance
- Diurnal fluctuation
- Eye fatigue
- Foreign body sensation
- Increased blinking frequency
- Irritation
- Mild itching
- Mucous discharge
- Photophobia
- Redness
- Stinging
- Tearing
- Symptoms may be aggravated by wind, air travel, low humidity, prolonged use of the eyes associated with decreased blink rate, or smoky environments
- Increases evaporation or causes irritation that worsens DES symptoms
Risk Factors
- Older age
- Female
- Estrogen hormone replacement therapy
- Androgen and vitamin A deficiencies
- Antihistamine, antidepressants, anti-anxiety medications
- Decreased intake of omega-3 fatty acids
- Ocular conditions (eg seborrheic blepharitis, meibomian gland dysfunction, ocular rosacea)
- Connective tissue diseases (eg Sjögren syndrome, rheumatoid arthritis)
- Systemic diseases (eg thyroid disease, Parkinson's disease)
- Viral infections such as hepatitis C infection, human immunodeficiency virus (HIV)
- Radiation therapy
- Hematopoietic stem cell transplantation
- Laser-assisted in situ keratomileusis (LASIK) and refractive excimer laser surgeries
