Why I Look at Your Eyes in the Consultation Room

When you sit down in my consultation room, the first thing I look at is your eyes.

This is true even when you have not come because of an eye problem. It is the same for the person who came with indigestion and the person who came with back pain. Because some people ask me why, today I want to talk about that.

The eye is the only place in the body where you can look directly, from the outside, at living blood vessels and nerves. Everywhere else is hidden beneath the skin. Only the eye is open.

The color inside the eyelid

If you gently pull down the lower eyelid, you can see the mucous membrane on the inside. When you are healthy, it is a vivid pink.

When this color is pale, the first thing I think of is anemia. When there is too little blood, the color drains first from this thin membrane.

There is a line to draw here, though. This pallor is a clue, not a test. Measured properly, it shows up in only about half of the people who are actually anemic. So pallor is a reason to check, but its absence is not a reason to rule anemia out. That is why I use it not as a conclusion but as a reason to send you for a blood test.

Conversely, when the white of the eye takes on a yellow tint, the story changes. Jaundice shows in the eye before the skin. What I find interesting is why. Bilirubin binds readily to a protein called elastin — and in the white of the eye, the elastin-rich layer is not the sclera, the white shell itself, but the thin conjunctiva laid over it. So what actually turns yellow is the conjunctiva, not the sclera. It can be a signal that something has happened in the liver or the bile ducts.

The time of day the eyelid swells

Swelling of the eyelid is common. What matters, though, is when it swells.

If it is especially bad in the morning and subsides as the day goes on, I give the kidneys a thought. It is because the fluid that pooled toward the face while you were lying down is not draining away.

If the legs swell in the evening, the story is different again. Even with the same swelling, what the body is saying differs depending on where and when it swells.

Eyelid twitching

This is a question I get often. "My eye keeps twitching — why is that?"

Usually it is fatigue, caffeine, stress, or lack of sleep. It disappears after a few days of rest. I see this kind of twitch as a mild warning the body is sending. It means the autonomic nervous system has become overly sensitive.

The following cases, however, are different.

• When the twitching continues for several weeks or more
• When it goes beyond the area around the eye and the whole of one side of the face moves along with it
• When the eyelid closes on its own and is hard to open

In these cases it may not be simple fatigue, so I recommend seeing a neurologist.

When the eyelid droops

One eyelid drooping is called ptosis. Gradual drooping with age is common.

But if suddenly only one side droops, and the following come with it, the story changes entirely.

• Objects appear doubled
• The two pupils are different sizes
• The eye does not move well

This may not be a problem of the eye but a problem of the nerves that move the eye. Do not delay — you must go to the hospital.

One more thing: if the eyelid grows heavier as evening comes and is fine in the morning, one can suspect a disease in which the muscles tire easily (myasthenia gravis). The clue is that it changes over the course of the day.

When the eye turns red — pain is the fork in the road

Redness is common. In most cases it is nothing to worry about. But I always check one thing. Does it hurt, or not?

Condition	Common cause	What to do
Red but not painful	Conjunctivitis, eye strain	Time usually resolves it
Red and severely painful + vision blurs	Acute glaucoma, keratitis, uveitis	Go to an ophthalmologist immediately
Only one spot is vividly red	Bleeding under the conjunctiva	Usually reabsorbs on its own

In particular, if severe eye pain + redness + reduced vision + headache and nausea come together, it may be acute glaucoma. This is an emergency that can cost you your sight. A few hours matter.

One paragraph, if you remember nothing else

If vision suddenly goes, or objects suddenly double, or one eyelid droops while the pupils turn unequal, or severe eye pain arrives together with redness and blurred vision — an ophthalmologist or an emergency room comes before a Korean medicine clinic. At that point it may not be the eye at all but the cerebral vessels, the nerves, or the pressure inside the eye, and the eye is only the window it shows through. When I meet someone like this, I set treatment aside and send them to the hospital first.

Why do the eyes show us so much

The old medical texts, too, regarded the eyes as important. If the whites of the eyes were yellow, they examined the liver and gallbladder (肝膽); if the eye was pale, they read it as a deficiency of blood (血).

I do not deny this long-standing observation. I only read it anew in modern language.

What is seen in the eye	Old expression	Today's language
The whites are yellow	Damp-heat of liver and gallbladder	Bilirubin binding to elastin in the conjunctiva — liver and bile ducts
The inside of the eyelid is pale	Blood deficiency	Anemia, low blood volume
The eye is bloodshot	Flaring liver fire	Problems of conjunctiva, uvea, intraocular pressure
The eyelid swells	Fluid-damp stagnation	Kidney, heart, protein deficiency
The eye is dry and gritty	Yin deficiency	Tear-film abnormality, autoimmunity

What the old people saw was the fact that the whole body is reflected in the eye. That observation still holds. It is only that today we can say a little more about why it is so.

Finally

I imagine some readers will look into their own eyes in the mirror after reading this. That is fine. I only want to say two things.

First, do not diagnose yourself. A slightly whitish inside of the eyelid does not mean anemia. What I have written here is not a diagnosis but a direction to look in.

Second, please remember the emergency signals written above. If you remember just that, this piece has done its part.

Looking at the eyes in the clinic is not to guess a disease name. It is to grasp the direction of where this body is now wavering — whether the blood is short, whether the flow is blocked, whether the nerves are exhausted.

And when I meet something I cannot help with, sending you to a place that can help is also part of the practice of medicine.

References

• Diagnostic accuracy of conjunctival pallor for anemia — sensitivity 43.6%, specificity 81.4%. A clue, but no substitute for a test — BMC Pediatrics, 2005
• Bilirubin binds readily to elastin, and elastin is abundant in the conjunctiva and episclera rather than the sclera — so "conjunctival icterus," not "scleral icterus," is the accurate term — American Family Physician, 2005
• Acute angle-closure glaucoma — severe unilateral eye pain, headache, blurred vision and nausea, with intraocular pressure rising to 50–80 mmHg and irreversible sight loss if treatment is delayed — StatPearls, 2026

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Written by Dr. Heo Ji-young (PhD in Korean Medicine Pathology, Kyung Hee University · former Research Professor of Herbology, Kyung Hee University)