Mr. Su was 25 when he went to a clinic for routine laser eye surgery, only to be blindsided by an unexpected diagnosis: glaucoma.
Three years later, a health check revealed a sharp decline in his right eye's vision. A referral to a medical center confirmed his intraocular pressure had surged to 40 mmHg. Now 32, Su has lost the right half of his visual field. If he closes his left eye, he is left with fragmented images and near-total blindness.
Su's case highlights a growing health crisis. Glaucoma—a chronic, irreversible degenerative disease of the optic nerve—is the leading cause of irreversible blindness worldwide. In Taiwan, physicians estimate that more than 525,000 people have the condition, with the patient population growing at an average rate of 5% each year.
The 'Invisible' Threat to Younger Generations
While traditionally viewed as a disease of the elderly, glaucoma is increasingly affecting younger demographics. According to 2024 data, 122,659 glaucoma patients in Taiwan are under the age of 50, accounting for roughly one in four cases (23.3%).
Dr. Lu Ta-wen (呂大文), chairman of the Taiwan Glaucoma Care Association and a specialist at Tri-Service General Hospital, attributes this demographic shift partly to Taiwan's high rates of myopia (nearsightedness) and the prolonged use of digital devices. He warned that between 50% and 80% of patients are completely unaware they have the condition, as most cases are discovered incidentally during routine health screenings.
Crucially, Lu noted a major misconception regarding eye pressure.
"Many people assume that normal intraocular pressure means they are fine," Lu said. "But in Asian populations, up to 85% of glaucoma cases are normal-tension glaucoma—far above the global average of 40%."
Because pressure readings alone can be deceptive, specialists emphasize that the true measure of optic nerve deterioration must be assessed through a visual field test, specifically looking at the Mean Deviation (MD) value.
Tracking the Decline: The Importance of MD Values
Dr. Chen Yi-hao(陳怡豪), also a glaucoma specialist at Tri-Service General Hospital, explained that the MD value is the most critical indicator for assessing both the severity of the disease and how rapidly it is worsening.
"The goal of glaucoma treatment is not to restore vision, but to apply the brakes to the MD value's rate of decline to preserve future visual field," Chen said.
A single examination is not enough; doctors must track the trajectory over time. If a patient's MD value falls by more than 1 dB per year, the disease is accelerating, and serious visual impairment could occur within 10 to 20 years. For example, a 30-year-old with an MD of -10 dB who loses more than 1 dB annually faces a high risk of near-blindness by age 50. Conversely, if treatment flattens the decline to just 0.2 to 0.3 dB per year, most patients can retain functional vision for life.
Shifting Treatment Paradigms
Treatment strategies vary based on the disease's stage, encompassing medication, laser therapy, and surgery. Dr. Li Yung-sung (李泳松), a physician at Linkou Chang Gung Memorial Hospital, noted that while prescription eye drops are the first-line defense, international guidelines recommend using no more than three types simultaneously.
When drops cause intolerable side effects—such as severe dryness, redness, or itching—or when they fail to stabilize intraocular pressure, it is time to consider surgical intervention. Historically, patients have resisted surgery due to fears of large incisions, hospitalization, and long recovery periods.
However, Li highlighted a newer, minimally invasive option: micro-invasive bleb surgery using a catheter. This outpatient procedure involves precisely implanting a microscopic catheter to create a drainage channel for the eye's aqueous humor, largely avoiding disruption to surrounding ocular tissue.
With a high safety profile and a recovery time of just one to two weeks, the minimally invasive approach is particularly suited for younger, working-age patients who need to quickly resume their daily lives. By intervening earlier, doctors can more effectively slow the ongoing loss of the visual field.
Ultimately, glaucoma is a lifelong condition that requires continuous management. Experts strongly advise regular comprehensive eye exams for high-risk groups.
As Dr. Lu reminded patients, the key question in glaucoma care is not whether you can see clearly today, but what steps you are taking to ensure you maintain your vision for decades to come. （Related： Medical Experts Urge Maternal Vaccination as RSV Threatens Taiwan's Newborns ｜ Latest ）
