Types of Dry Eye Disease

There are different types of dry eye disease, with different causes behind them.^1a,2a,3a

Evaporative dry eye disease

Evaporative DED is the most common type of dry eye disease, with an estimated 80% of people with DED having the evaporative type.^3a,4a It occurs when the protective tear film that covers the eye evaporates too quickly, meaning the eyes lose too much moisture.^1b Your eyes need this tear film to keep them healthy and protect them from environmental damage.^5a

Some causes of evaporative DED are intrinsic (internal), while others are extrinsic (external).^1b

Intrinsic causes include:

Low blink rate, which can be caused by computer work, surgical procedures or disorders like Parkinson’s disease^1e,6a
Disorders of the eye’s lid aperture,* which may increase the exposed surface of the eye^1d
Meibomian gland dysfunction (MGD), a condition where the eye’s meibomian gland is obstructed^1c

Tear film, lacrimal gland and meibomian gland⁷

Adult,Daughter,Visits,Senior,Father,In,Assisted,Living,Home.,Portrait

Extrinsic causes include:

Vitamin A deficiency, which makes the protective tear film unstable and causes it to break up too quickly^1f
Preservatives found in certain eye drops, which can damage the surface of the eye^1f
Topical^† anaesthetics, which reduce tear production and blink rate^1f
Contact-lens use, which causes discomfort and dryness in the eyes^1g
Ocular surface disease,^‡ seasonal allergies and inflammatory conditions like allergic conjunctivitis^§1n

Aqueous-deficient dry eye disease

Aqueous-deficient DED occurs when the lacrimal glands^¶ in your eyes don’t produce enough tears.^1h The tear film is a protective layer that covers the surface of your eyes, keeping them moist and healthy;^5a if your eyes aren’t producing enough tears, they will dry out too quickly.^1h An estimated 10% of people with DED have the aqueous-deficient type.^4a

There are two main types of aqueous-deficient DED:¹¹

Sjögren’s syndrome dry eye: Caused by an autoimmune condition called Sjögren’s syndrome, which affects the lacrimal glands and salivary glands^1j
Non-Sjögren’s syndrome dry eye: Caused by underlying issues other than Sjögren’s syndrome, such as ageing or an obstruction in the lacrimal glands^1k,l

Other causes of dry eye disease

Some other potential causes of DED not mentioned above include:

Hormonal changes during pregnancy and menopause^6b
Conditions with low humidity and/or high winds^1m,4a
Air-conditioned environments^1m,4a
Reading or driving for long periods of time^4a
Exposure to second-hand smoke^4a
Chronic illnesses like diabetes and glaucoma^4a
Certain medications, including oral contraceptives, antivirals and antidepressants^4a

Products for Dry Eye Disease: Visu

Products for Dry Eye Disease: Xailin

*The gap between the margins of the eyelids when the eye is open^8a^†Applied to a surface area, rather than taken internally or injected, e.g. eye drops or skin ointments^9a^‡Disease of or damage to the surface layers of the eye, i.e. the cornea and conjunctiva^10a^§Allergy-related inflammation in the conjunctiva, the clear layer of tissue lining the eyelids and covering the white of the eye^11a^¶The glands that produce tears, located just above the upper outer corner of the eyes^12a