Common Causes of Dry Eyes
Dry eye disease results from two primary mechanisms—tear film instability (most common) and deficient aqueous tear production (least common)—with most patients having multiple contributing factors. 1
Primary Pathophysiologic Mechanisms
The American Academy of Ophthalmology identifies that tear film instability is more common than aqueous deficiency alone, with combined-mechanism dry eye being the typical presentation. 1 The lacrimal functional unit dysfunction leads to an unstable tear film that causes ocular irritation and potential epithelial damage. 1
Major Risk Factors
Demographic Factors
- Older age is a major risk factor, with dysfunction developing from age-related changes and decreased supportive factors like androgen hormones 1
- Female gender is consistently identified as a significant risk factor 1
- Postmenopausal hormone replacement therapy, particularly estrogen use alone, increases risk 1
Systemic Inflammatory Diseases
- Sjögren's syndrome (most important autoimmune cause) 1
- Rheumatoid arthritis 1
- Autoimmune thyroid disease 1
- Systemic lupus erythematosus 1
- Graft-versus-host disease (GVHD) 1
- Stevens-Johnson syndrome 1
Medications (Critical to Identify)
- Antihistamines 1
- Antidepressants and antianxiety medications 1
- Diuretics 1
- Anticholinergics (any medication with anticholinergic effects) 1
- Systemic retinoids (isotretinoin for acne) 1
- Oral corticosteroids 1
- Topical glaucoma medications containing benzalkonium chloride 1
- Frequent use of preserved eye drops (>4 drops daily) causes corneal epithelial breakdown 1
Ocular and Surgical Causes
- Meibomian gland dysfunction (more common than pure aqueous deficiency) 1
- Blink and eyelid abnormalities 1
- LASIK and SMILE surgery (disrupts trigeminal afferent sensory nerves) 1
- Contact lens wear 1
- Ocular surface diseases (HSV keratitis) 1
Environmental and Lifestyle Factors
- Extended screen time with reduced blink rate 1
- Low humidity environments (air conditioning, heating, wind) 1
- Reading or driving (prolonged visual tasks with decreased blinking) 1
- Smoking 1
Other Systemic Conditions
- Diabetes mellitus (17.5% prevalence, especially with poor metabolic control) 1
- Rosacea (dermatologic and ocular manifestations) 1
- Sleep disorders (sedative-hypnotic use may be associated) 1
- Neurological conditions (Parkinson disease, Bell's palsy) 1
Pediatric-Specific Causes (Often Overlooked)
Clinicians should recognize that pediatric dry eye can result from: 1
- Congenital conditions (alacrima, ectodermal dysplasia, familial dysautonomia)
- Autoimmune diseases (juvenile rheumatoid arthritis, Sjögren's syndrome)
- Dermatologic conditions (acne rosacea, Stevens-Johnson syndrome)
- Nutritional deficiencies (vitamin A deficiency, malabsorption syndromes)
- Post-infectious causes (measles, Epstein-Barr virus)
Clinical Pitfalls
Multivitamin use was associated with increased dry eye risk, while caffeine use was associated with decreased risk. 1 ACE inhibitors were associated with lower risk. 1 These counterintuitive findings should be considered when evaluating patients.
Environmental irritants and allergens are not causative but may aggravate existing symptoms. 1