Normal-Tension Glaucoma: Why Regular Eye Exams Matter
You can read a book, recognize faces, and see clearly across a room while a serious eye condition quietly develops. Glaucoma can damage the optic nerve before noticeable vision problems appear, making routine eye examinations essential even for people who believe their eyesight is perfectly healthy.
In a report published by Seoul Economic Daily on October 17, 2026, Dr. Na Jung-hwa, director of the Glaucoma Center at Hangil Eye Hospital in South Korea, explained why normal eyesight and an eye pressure reading within the usual range do not necessarily rule out glaucoma.
One important concern is normal-tension glaucoma, a form of the disease in which optic nerve damage occurs despite pressure measurements that fall within the generally accepted normal range. Recognizing this possibility can help people understand why comprehensive eye examinations involve more than reading letters on a chart.
How Glaucoma Can Develop Without Obvious Symptoms
The optic nerve carries visual information from the eye to the brain. When glaucoma damages this nerve, a person can gradually lose portions of their visual field, often beginning with peripheral vision rather than the central vision used for reading and recognizing objects.
Because these changes may be difficult to notice during everyday activities, a person can continue performing normal tasks while the disease progresses. Symptoms often become more apparent only after damage has accumulated.
Visual acuity tests measure how clearly someone can see specific details, but they do not provide a complete picture of optic nerve health. A person may achieve 20/20 vision and still have glaucoma-related damage that requires further investigation.
Eye pressure is another important measurement, but it also has limitations. According to Dr. Na’s explanation in the Seoul Economic Daily report, pressure levels that are tolerated by one person’s optic nerve may be associated with damage in another.
This is why glaucoma screening should assess the optic nerve itself rather than relying exclusively on how clearly someone sees or whether their pressure measurement appears normal.
What Is Normal-Tension Glaucoma?
Normal-tension glaucoma is a type of glaucoma in which characteristic optic nerve damage develops without an elevated intraocular pressure reading according to the usual reference range. It demonstrates that pressure is an important risk factor, but not the only consideration when evaluating the disease.
The Seoul Economic Daily report notes that normal-tension glaucoma accounts for a large share of glaucoma cases in South Korea. It also cites an average eye pressure of approximately 14 millimeters of mercury (mmHg) among Koreans.
That figure describes a reported population average, not a target pressure that guarantees protection from glaucoma. Individual susceptibility varies, and a measurement of 15 mmHg, for example, cannot by itself determine whether someone’s optic nerve is healthy.
Eye pressure can contribute to mechanical stress on the optic nerve, but other factors may influence how the nerve responds. The precise reasons why some people develop glaucoma at relatively low pressure remain an important area of medical investigation.
Normal-tension glaucoma also illustrates why a single reassuring result should not replace a complete examination. If an eye-care professional notices suspicious optic nerve changes, additional testing may be necessary even when pressure readings fall within the expected range.
Who Should Consider Regular Glaucoma Screening?
Age, family history, myopia, and elevated intraocular pressure are among the factors associated with increased glaucoma risk. The likelihood of developing the disease generally rises as people grow older.
Dr. Na recommends regular optic nerve examinations for people aged 40 and above, those with relatives who have glaucoma, people with myopia, and individuals who have previously been told that their eye pressure is high.
Family history deserves particular attention. The report describes findings from some studies suggesting that glaucoma risk may be more than twice as high when a parent has the disease and more than three times as high when a sibling is affected. These figures are study-dependent estimates, not predictions of an individual’s personal outcome.
Myopia, or nearsightedness, is another relevant consideration. Greater degrees of myopia can be associated with changes in the shape of the eyeball and the structure around the optic nerve, potentially complicating assessment and increasing susceptibility to glaucoma.
People whose health screening reports mention suspected glaucoma or an increased cup-to-disc ratio should also seek a detailed eye examination. The cup-to-disc ratio describes the appearance of the optic nerve head, and an unusual measurement may warrant further evaluation rather than automatically confirming a diagnosis.
Which Tests Help Detect Glaucoma Early?
A comprehensive glaucoma assessment combines several examinations because no single measurement can establish the full condition of the eye.
Tonometry measures intraocular pressure. It helps identify elevated pressure, but normal results do not exclude glaucoma, particularly normal-tension glaucoma.
Optic nerve examination allows an eye-care professional to inspect the nerve head for structural changes associated with damage. The cup-to-disc ratio and the appearance of the surrounding nerve tissue may provide important clues.
Optical coherence tomography (OCT) produces detailed images of retinal and optic nerve structures. It can measure the thickness of nerve fiber layers and help identify changes that may not be obvious from visual acuity testing alone.
Visual field testing assesses how well a person detects objects or points of light in different parts of their field of vision. This can reveal areas of reduced sensitivity associated with glaucoma.
Gonioscopy allows the clinician to examine the drainage angle inside the eye. This helps distinguish open-angle from angle-closure glaucoma and guides decisions about appropriate management.
Doctors interpret these results together, considering the person’s medical history, risk factors, optic nerve appearance, and changes over time. If glaucoma is suspected, follow-up testing may be needed to clarify the diagnosis and monitor progression.
Glaucoma Treatment and Daily Habits That Matter
Current glaucoma treatment focuses on preventing additional optic nerve damage. Nerve tissue already lost to glaucoma generally cannot be restored with available treatments, so identifying the disease early and maintaining effective management are especially important.
Lowering intraocular pressure is the best-established approach for slowing glaucoma progression, including in many people whose pressure was not elevated initially. The appropriate pressure target depends on factors such as existing damage, disease progression, and individual risk.
Treatment may involve prescription eye drops, laser procedures, or surgery. Selective laser trabeculoplasty (SLT), for example, uses laser energy on the trabecular meshwork to improve fluid drainage in suitable patients. Surgery may be considered when other approaches do not control pressure adequately.
Because glaucoma is usually a long-term condition, patients should follow their prescribed treatment and attend scheduled monitoring appointments. Stopping treatment simply because vision feels unchanged can leave progressive damage undetected.
Some activities can temporarily increase eye pressure. The report advises caution with heavy lifting and head-down positions, such as handstands, for people with glaucoma. Patients with advanced disease or unusual progression should discuss exercise and sleeping positions with their eye-care professional.
Ordinary smartphone or computer use has not been established as a direct cause of worsening glaucoma. Taking breaks for comfort may help with digital eye strain, but screen habits are not a substitute for glaucoma monitoring and treatment.
When Should You See an Eye Doctor?
Arrange a comprehensive eye examination if you are over 40 and have not had appropriate screening, have a family history of glaucoma, have significant myopia, or have previously received an abnormal optic nerve or eye pressure result. Your clinician can recommend an examination schedule based on your individual risk.
Seek urgent medical attention if you develop sudden severe eye pain, redness, blurred vision, rainbow-colored halos around lights, a severe headache, nausea, or vomiting associated with eye symptoms. These can be warning signs of acute angle-closure glaucoma, which requires immediate assessment.
Most importantly, do not wait for noticeable vision loss before checking your eye health. Schedule a comprehensive examination and ask whether optic nerve imaging and visual field testing are appropriate for you, especially if you have risk factors or have been told that your results are suspicious.
Early detection cannot guarantee that glaucoma will never affect vision, but timely diagnosis and consistent treatment can help preserve sight for longer. Even when your eyesight seems clear and your pressure reading looks normal, regular monitoring remains a practical investment in your long-term eye health.
