Glaucoma vs Normal Eye Pressure: What Every Adult in Seoul Should Know

Why “normal” eye pressure does not rule out glaucoma — a practical guide for residents and expats in Yeongdeungpo, Guro, Gasan and Gwanak

Q. What is the difference between glaucoma and normal eye pressure?

Eye pressure is a measurement; glaucoma is a disease. Intraocular pressure (IOP) is the fluid pressure inside the eye, commonly cited as a statistical range of roughly 10–21 mmHg. Glaucoma is a progressive optic neuropathy in which retinal ganglion cells and their fibres are lost, producing a characteristic cupping of the optic nerve head and gradual loss of visual field. High IOP is the best-known risk factor and the only one we can currently treat, but a person can have glaucoma with pressure inside the “normal” range, and a person can have pressure above 21 mmHg without ever developing nerve damage (ocular hypertension).

This distinction matters for adults across Yeongdeungpo, Guro, Gasan and Gwanak, where many patients tell us they were reassured by a “normal” pressure reading at a workplace health screening or glasses shop. Non-contact “air-puff” readings are a screening estimate; they cannot show the optic nerve, the drainage angle or the visual field.

Q. Why can glaucoma happen with normal eye pressure?

Normal-tension glaucoma occurs when the optic nerve is damaged even though IOP stays within the statistical normal range. Several factors are thought to contribute: an optic nerve that is individually vulnerable to pressure, reduced blood flow to the nerve (for example with very low blood pressure at night, migraine or vasospasm), thin corneas that make a reading look lower than the true pressure, and high myopia, which changes the structure of the optic nerve head. Studies in Korea and Japan have found that normal-tension glaucoma accounts for a large share of open-angle glaucoma in East Asian populations, which is why pressure alone is an unreliable safety net here.

Pressure also fluctuates through the day and is often highest at night, when we are lying flat. A single clinic reading at 2 p.m. can miss the peak. Central corneal thickness (pachymetry) is therefore measured to correct readings, and in selected patients repeat measurements at different times of day are useful.

Q. What are the symptoms and signs of glaucoma?

Most chronic open-angle glaucoma has no symptoms in the early and moderate stages, which is exactly why it is called the “silent thief of sight”. Peripheral vision is lost first, and the brain fills in the gaps, so many people notice only when the central field is affected. Signs that may appear later include:

Q. How is glaucoma diagnosed and treated?

Diagnosis rests on several tests done together: tonometry (IOP), gonioscopy (looking at the drainage angle), optic nerve and retinal nerve fibre layer assessment by OCT, a visual field test, and corneal thickness. One abnormal test is rarely enough; the pattern and change over time matter, so follow-up scans are compared with a baseline.

Treatment is built around lowering pressure to a target for that individual. Options include prescription eye drops (the usual first step), laser trabeculoplasty or laser iridotomy for selected eyes, and surgery when drops and laser are not enough. Even in normal-tension glaucoma, lowering IOP by a meaningful percentage slows progression. Regular follow-up, with repeat visual fields, is as important as the medication itself.

Q. What can I do between check-ups to protect my optic nerve?

Use prescribed drops exactly as directed and tell your doctor about every steroid product you use, including creams, inhalers and eye drops, since steroids can raise IOP. Avoid skipping follow-up visits when you feel fine; glaucoma progress is measured on scans and visual fields, not by how you feel. Moderate aerobic exercise is generally considered safe and may help circulation, while heavy head-down positions can transiently raise pressure, so ask about yoga inversions. If you live or work around Yeongdeungpo, Gasan, Guro or Gwanak, choosing one clinic for all follow-up scans lets the same equipment compare your results year after year, which makes small changes easier to spot.

Q. How can foreigners in Seoul get a glaucoma check-up?

Foreigners living in Korea can see an ophthalmologist directly; a specialist referral is generally not required for a private eye clinic. Book through Naver Booking (the button below) or contact the clinic to arrange an English consultation. Bring your passport or Alien Registration Card (ARC), your current glasses or contact lens details, a list of any eye drops and medicines you use, and any prior records, such as OCT or visual field printouts and your last prescription from home. Whether a visit is covered by the national health insurance or paid out of pocket depends on your enrolment status and the tests involved, so ask the clinic for a current quote before the visit. A typical visit includes history, vision and pressure testing, a dilated or undilated look at the optic nerve, OCT imaging and, if indicated, a visual field test, followed by a plain-language explanation in English or Korean at Nunehim Eye Center in Guro-gu, easily reached from Gasan, Gwanak and Yeongdeungpo.

Q. What types of glaucoma should I know about?

Dr. Daniel Baik’s Clinical Tip

“Do not judge your risk by one pressure reading. If your family has glaucoma or you are highly myopic, ask for an OCT of the optic nerve and a visual field test as a baseline, and keep the printouts. The earliest sign we act on is change between visits, so a baseline from today makes every future check far more meaningful.” — Dr. Daniel Baik, board-certified ophthalmologist

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