Menopause and pregnancy can cause thickening of the oils in the meibomian glands and cause them to block.
Prolonged computer use
Poor blinking and staring at screens and, in particular, digital devices like iPhones. This reduces our blink rate considerably and exposes the eyes.
This allows the air (especially in air-conditioning) to dehydrate the ocular surface.
Dry climates, pollution, wind and air conditioning or fans can all increase evaporation of tears from the ocular surface. Beware of moving air!
As we age, the eyelids can sag away from the eyeball, so the important oils from the meibomian glands can’t enter the tear film.
Certain systemic diseases such as Rheumatoid Arthritis and Lupus can effect aqueous tear production. Sjogren Syndrome is an autoimmune disease that effects the aqueous tear glands as well as the salivary glands. Read more here.
Medications such as antidepressants and antihistamines can cause meibomian glands to block or aqueous tear production to be reduced (or both).
In this common disorder, the eyelids become inflamed and crusted. This impairs meibomian gland function by blocking the openings to the oil glands.
This is where the eyelids do not fully close during sleep, leading to an exposed ocular surface.
Contact lens wear
Lenses not only soak up available moisture in the eye, but also interfere with the tear film.
Meibomian gland dysfunction / MGD
Blocked oily tear glands are one of the most frequent causes of dry eye.