Dry eye syndrome classification (Agenda series Part.02-2)

“Classification of dry eye syndrome”

Hello, this is easy-to-understand ophthalmology story.

Following the causes of dry eye syndrome in the past, this time, we will look at classification according to the causes .

Dry eye syndrome classification

There are four main types of dry eye syndrome, depending on the cause.

  1. lack of moisture
  2. Blepharitis, related to meibomian gland disorders
  3. mucin deficient type
  4. exposure

Below that, the detailed cause classification can be done as follows.

Dry eye syndrome classification
Dry eye syndrome classification

Quite complicated and there are many types, right?

Most patients with dry eye syndrome have more than one complex cause, not just one type.

Other than the four categories, “eye disease-related” are diseases that are not dry eye syndrome, but have similar symptoms to dry eye syndrome and can be mistaken for dry eye syndrome.

Let’s take a look at each one.

lack of moisture

It is a type in which the moisture layer component of the tear film is reduced .

tear film
tear film

It is caused by a problem in the lacrimal gland that produces water for tears or the duct that drains the tears .

The water content of tears decreases, and the osmotic pressure (salinity) of tears increases, causing dry eye syndrome .

A typical example is Sjogren’s syndrome .

It is a type of autoimmune disease in which the body attacks and destroys the lacrimal glands.

However, dehydration dry eye syndrome is a rare type of dry eye syndrome .

Blepharitis/Meibomian Gland Disorder

The eyelids are divided into anterior and posterior parts according to their position .

Dry eye syndrome classification (Agenda series Part.02-2)
front and back eyelids

Inflammation of the anterior eyelid can be caused by a skin disease such as seborrhea or atopic dermatitis or a bacterial infection such as Staphylococcus aureus .

anterior blepharitis
anterior blepharitis

When anterior blepharitis occurs, it is characterized by redness along the eyelids and the formation of debris on the eyelashes .

These blepharitis can cause inflammation, which can make dry eyes worse.

The rear eyelid is the part where the meibomian glands are located .

The meibomian gland is a sebaceous gland, a very important tissue that creates an oil layer that prevents the evaporation of tears.

meibom gland
meibom gland

Inflammation of the rear eyelid is a problem of the meibomian gland, and the oil layer of the tear film becomes unstable , causing excessive evaporation of tears .

This is also known as “evaporative dry eye syndrome .”

meibomian gland disorder
meibomian gland disorder

Posterior blepharitis is a problem (blockage, inflammation) of the meibomian gland as above, which causes dry eye syndrome.

This type of dry eye syndrome is the most common type, accounting for about 84% of all cases.

This may be the reason why patients with dry eye syndrome should carefully examine their eyelids .

mucin deficient type

Mucin is a substance secreted by specific cells (goblet cells) of the conjunctiva (white), and makes the tears adhere well to the surface of the eyeball .

Dry eye syndrome classification (Agenda series Part.02-2)

The role is to help the tears spread evenly over the surface of the eyeball.

Some eye disorders (scarring conjunctivitis), Steven-Johnson syndrome contact lens wear, and vitamin A deficiency reduce the number of goblet cells that make mucin and

Mucin secretion is reduced and dry eye syndrome is induced.

Vitamin A deficiency is uncommon in normal people, but may occur in patients who have had gastric surgery .

In addition, excessive use of eye drops can also reduce mucin secretion, so it is necessary to check the eye drops currently being instilled, such as glaucoma medications.


The blinking action of the eyelids allows our eyes to maintain a normal, constant amount of water.

However, if the eyelids do not close completely, or if the number of blinks is abnormally small or large, dry eye syndrome occurs .

Because the cornea is exposed abnormally in the above situation, it is called “exposed dry eye syndrome” .

First, muscle abnormalities like facial paralysis or Parkinson’s disease sometimes invade the muscles related to the eyelids , causing exposure dry eye syndrome.

Second, even if it is not a specific disease , actions that focus on something, such as driving, reading, or a smartphone, can unconsciously reduce the number of blinks.

Third, exposure to dry eye syndrome in which the eyelids do not close completely can occur due to double eyelid surgery or ptosis surgery .

 Corneal exposure after eyelid surgery - Dry eye syndrome classification
Corneal exposure after eyelid surgery

Eye disease related

Dry eye symptoms experienced by patients can sometimes be caused by causes other than the above four categories.

Various diseases such as allergic conjunctivitis, atopic conjunctivitis, and upper limbal keratoconjunctivitis can overlap with dry eye symptoms.

Sometimes it accompanies dry eye syndrome and worsens dry eye syndrome.

Therefore, the accompanying ophthalmic disease must be identified and treated at the same time .


So far, we have discussed the classification of dry eye syndrome.

Now, I think you know that dry eye syndrome is not just a dry disease.

Over time, with advances in science and technology, the understanding of dry eye syndrome has increased and its classification has diversified.

What else may be revealed in the future.

Dry eye syndrome is a disease for which there is no definitive treatment yet, only management is best.

In the next post, we will look at various methods of diagnosing dry eye syndrome based on the information we have given so far.

Thank you for reading this long post, and please use the community for any questions.

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