Causes, Symptoms, and Prevention of Dry Eye | Rohto Pharmaceutical: Product Information Site

<Things you should know> The correct knowledge about "dry eye": Causes, symptoms, and prevention methods for "dry eye"

What is dry eye?
Main symptoms of dry eye
Main causes of dry eyes
How to deal with dry eye (examination/treatment)
How to prevent dry eyes (things you can do in your daily life)
Diagnostic criteria and self-check for dry eye
Can dry eyes improve? Can they be completely cured?

In recent years, more and more people are experiencing dry eyes and eye strain due to prolonged use of computers and smartphones. This discomfort may be caused by dry eye syndrome. This article, supervised by an ophthalmologist, provides a detailed explanation of the causes, prevention, and treatment of dry eye syndrome.

What is dry eye?

Dry eye is also known as "keratoconjunctivitis sicca." It is a condition caused by various factors that lead to a decrease in tear production or a deterioration in tear quality, resulting in eye discomfort, visual impairment, and sometimes even damage to the surface of the eye.

Types of dry eye

Dry eye can be broadly classified into two types: "quantitative abnormalities of tears" and "qualitative abnormalities of tears." "Quantitative abnormalities of tears" refer to a condition where the amount of tears decreases, resulting in insufficient tear secretion. On the other hand, "qualitative abnormalities of tears" refer to a change in the ability to retain tears due to abnormalities in the components of the tears.

The structure of tears

Tears consist of an oil layer, a water layer, and a membrane-forming mucin layer, and the balance of these layers maintains the stability of tears. When these layers become unstable, tears evaporate more easily. This type of dry eye is becoming more common among office workers who spend a lot of time working on computers and among people who wear contact lenses.

The structure of tears

Main symptoms of dry eye

Dry eye symptoms are not limited to just "dry eyes," but can also include eye fatigue, a gritty feeling, and redness. Wearing contact lenses can also be painful. Furthermore, recent studies have shown that dry eye can lead to decreased vision. If you experience any of the following symptoms, you may have dry eye.

My eyes get tired.
My eyes feel gritty.
My eyes feel dry.
I feel discomfort in my eyes.
My eyes are stinging and painful.
Red eyes
I have trouble opening my eyes in the morning.
My eyes are getting wrinkled.
A whitish discharge appears from the eyes.
It's kind of hard to see.
It sometimes appears hazy.
My eyesight seems to have deteriorated a little recently.

Main causes of dry eyes

Dry eye can be caused by a variety of factors, including environmental factors, aging, and illness, but environmental factors are considered to be particularly significant. These include reduced blinking due to prolonged use of computers and smartphones, and the dryness of indoor environments caused by air conditioning and heating. Lifestyle factors such as long-term and prolonged contact lens wear, a nocturnal lifestyle, changes in diet, and lack of exercise are also said to be contributing factors.
In addition, as we age, the amount of tears produced may decrease, or the quality of tears may deteriorate, making our skin more prone to dryness.

Furthermore, tear secretion is controlled by the autonomic nervous system; the parasympathetic nervous system, which is active during relaxation, stimulates tear secretion, while the sympathetic nervous system, which is active during stress, suppresses tear secretion. There is a theory that modern people are more prone to sympathetic nervous system activity due to various stresses, which may be suppressing tear secretion.

In addition, there are severe cases of dry eye caused by autoimmune diseases such as Sjögren's syndrome or diseases such as Stevens-Johnson syndrome, which destroy the tear glands, but these require diagnosis by an ophthalmologist.

How to deal with dry eye (examination/treatment)

Treatment options for dry eyes include eye drops and eye examinations. This article explains when to see an ophthalmologist for dry eyes, as well as the examinations and treatments available.

eye drops

Dry eye can also be treated with over-the-counter (OTC) medications *. Products containing ingredients that help regulate tear film balance (such as sesame oil, sodium chloride, potassium chloride, calcium chloride hydrate, sodium chondroitin sulfate, panthenol, and sodium hyaluronate) are effective.

*Medications that can be purchased without a prescription at pharmacies and drugstores.
Visit an ophthalmologist

If your dry eye symptoms worsen, if you feel that over-the-counter (OTC) medications are no longer effective, or if your eyes are so irritated that you need to use eye drops every 30-40 minutes, you should see an ophthalmologist. Be careful not to use eye drops too often, as this can wash away tears and actually damage the cornea.

Various tests are performed at the ophthalmology clinic. A common test to measure tear volume is the Schirmer test, in which a special filter paper is placed on the edge of the eyelid and the length of the paper that is wetted in 5 minutes is measured.

Additionally, a yellow staining solution is instilled into the eye, and the condition of the cornea and conjunctiva is examined using a microscope called a slit lamp. The same staining solution is also used for the "tear film breakup time (BUT) test." This test involves keeping the eye open without blinking to determine how long it takes for the tear film to break down.

For mild symptoms, eye drops that provide moisture are used. These include artificial tears, hyaluronic acid preparations, eye drops that promote mucin and water secretion (diquafosol sodium), and eye drops that stimulate mucin production (repamid).

A treatment called "punctal plugs" is covered by insurance. This involves plugging the puncta, the openings for tears, to block the physiological drainage of tears.

In addition, "eye thermotherapy," which warms the eyes with far-infrared rays, and the use of protective glasses to prevent tear evaporation may also be effective.

How to prevent dry eyes (things you can do in your daily life)

Most cases of dry eye stem from eye strain. Normal tears have a slightly viscous consistency, but when you're tired, tears become watery and thin, making your eyes more prone to dryness. Start by reviewing your daily habits and eliminating the causes of eye strain.

Rest your eyes

When working on a computer or looking at a screen, take a 15-minute break every hour to rest your eyes. Placing a warm, damp towel on your eyelids is also effective. The towel should be around 40 degrees Celsius, and you should leave it on your eyelids for about 10 minutes.
Use bifocals, computer glasses, or contact lenses.

When working on close objects such as computer screens, your eyes can easily get tired if your glasses or contact lenses are not the correct prescription. Using bifocals or glasses/contact lenses specifically prescribed for computer use is recommended to prevent eye strain. There are also contact lenses made of silicone hydrogel, which are less prone to dryness.
Blink consciously

When you concentrate too much on your computer or smartphone, you may blink less, so make a conscious effort to blink. Also, "incomplete blinking," where your eyes don't completely close even when you blink, can be a cause of dry eyes. This is especially true for people who use desktop computers with their eyes looking upwards. Position your computer screen so that it is below eye level.
One way to address "inability to blink" is to consciously keep your eyelids closed. This can help you learn to blink correctly in about two weeks. Additionally, tightly closing and then quickly opening your eyes while blinking stimulates the meibomian glands to release oil, which helps reduce tear evaporation.
Avoid applying eye makeup to the inner part of your eyelashes.

The meibomian glands are glands that secrete lipids, which are important for protecting the eyes from dryness.
If eye makeup blocks the meibomian glands located at the base of the eyelids, it can hinder oil secretion and cause dry eyes. Avoid applying eye makeup to the mucous membrane inside the eyelashes.
Massage the meibomian glands.

When washing your face in the morning and evening, with your eyes closed, place your fingertips together at the base of your eyelashes and gently move them back and forth 1-2 millimeters to massage your meibomian glands. Making this a habit will improve oil secretion and reduce tear evaporation.
Use of a humidifier

Maintain indoor humidity by using a humidifier or adjusting the air conditioner settings. It's also important to create a comfortable work environment where the air conditioner's airflow doesn't directly hit your face.
Consume foods with antioxidant properties.

Foods with antioxidant properties are said to relieve eye strain and improve tear quality. DHA and EPA, which are abundant in the oil of oily fish, astaxanthin, the pink pigment in salmon, and crocetin, the yellow pigment in gardenia and saffron, are thought to be effective.

Diagnostic criteria and self-check for dry eye

In 2016, the diagnostic criteria for dry eye were revised.

Subjective symptoms (discomfort such as dry eyes, or visual abnormalities such as poor vision)
BUT 5 seconds or less AND subjective symptoms (visual dysfunction such as eye discomfort or poor vision)

Based on these two criteria, I was diagnosed with dry eye.

The BUT test is an ophthalmological examination that measures how many seconds the tear film can cover the cornea after blinking, with the eye open. A result of 5 seconds or less is considered abnormal.

One study suggests that a good indicator for self-checking is whether you can refrain from blinking for 12 seconds. If you cannot, you may have dry eyes.

Can dry eyes improve? Can they be completely cured?

Dry eye, which causes eye strain, is caused by an abnormality in tear production. It usually improves with proper care, such as adjusting glasses or contact lenses. Some people even see improvement simply by being prescribed bifocal contact lenses. Dry eye that doesn't produce enough tears can be improved with eye drops, but a complete cure is difficult.

Dry eyes can cause unstable vision, but it's unlikely that dry eyes alone would lead to serious conditions like blindness. However, dry eyes make the cornea more susceptible to damage, and if it becomes infected with bacteria, it can lead to keratitis or conjunctivitis, potentially worsening the condition. If you experience dry eyes, including itching or discharge, in addition to dryness and fatigue, you should consult an ophthalmologist.

Supervised by: Dr. Masayoshi Kajita, Director of Kajita Eye Clinic
After graduating from Fukushima Medical University in 1983, he worked as a researcher at the University of California, Berkeley, before opening Kajita Ophthalmology Clinic in 2003. From 2018 to 2021, he served as a Clinical Professor at Tokyo Medical and Dental University School of Medicine. In 2022, he was awarded Honorary Membership by the Japan Contact Lens Society, and in 2023, Honorary Membership by the Japanese Society of Ophthalmic Optics. He currently serves as a councilor of the Japan Ophthalmological Society and a member of the drafting committee for the Japanese Medical Optics JIS standards.

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