Glaucoma Unnoticed by Eye Pressure Alone... Beware if You Have Myopia or Aging [Kok! Health]

Glaucoma is one of the top three causes of blindness identified by the World Health Organization (WHO). It is mainly known to occur due to high intraocular pressure (IOP), but since the level of IOP that the optic nerve can tolerate varies from person to person, it can develop even when the IOP is within the normal range. Especially because early symptoms are difficult to notice, by the time symptoms appear, glaucoma may have already progressed significantly. Therefore, those with myopia or aging eyes should be more cautious as they have a higher risk of developing the disease.

A patient undergoing a visual field test for glaucoma examination
[Photo by Kim Eye Hospital]

Glaucoma is a condition where relatively high intraocular pressure damages the optic nerve, causing a narrowing of the visual field. The term "high intraocular pressure" here does not refer to a specific number but rather to a level higher than the appropriate IOP that an individual's optic nerve can tolerate. The reason glaucoma is frequently found in older adults is that the optic nerve weakens due to aging of the eye.

Generally, the normal range of intraocular pressure is 10 to 21 mmHg. Because of this, it is easy to assume that glaucoma does not occur if the IOP is within this range. However, the normal IOP range is based on measurements taken from people without glaucoma, so it is difficult to conclude that glaucoma will not develop within this range. The IOP that an individual's optic nerve can tolerate may differ from the "normal IOP" range.

If the eye cannot tolerate it, glaucoma can develop even at an IOP of around 15 mmHg, whereas if the eye is more resilient to high pressure, glaucoma may not occur even if the IOP rises to 30 mmHg. Additionally, people with thin or soft corneas may have their IOP measured lower than it actually is, leading to a mistaken belief that their IOP is normal despite it being high.

Normal-tension glaucoma symptoms appear gradually, so in the early stages, one may not notice any abnormalities. In the mid-stages or beyond, symptoms such as a gradual narrowing of the visual field appear. This can result in situations like failing to notice surrounding vehicles changing lanes while driving, missing a tennis ball at certain moments, or misstepping when going down stairs due to missing parts of the visual field.

The fundamental treatment for glaucoma, including normal-tension glaucoma, is to lower the intraocular pressure to prevent further damage to the optic nerve. Medication treatment, primarily eye drops, is usually administered. If the IOP is not well controlled or if visual field deterioration continues despite IOP control, laser treatment or surgical treatment may be considered.

Glaucoma is a disease without a cure, but early detection and prompt treatment can prevent worsening. It is important to avoid behaviors that can increase IOP, such as drinking alcohol or smoking, and to regularly check IOP control and disease progression through routine examinations. Those with myopia or aging eyes have a relatively higher risk of developing normal-tension glaucoma, so regular check-ups should not be neglected.

Jongjin Jeong, a glaucoma specialist at Kim Eye Hospital Glaucoma Center, said, “Normal-tension glaucoma is difficult to detect, so it is recommended that people over 40, whose optic nerves may weaken with aging, undergo regular fundus examinations.” He added, “If you have normal-tension glaucoma, it is important to manage it with medication to prevent further increases in IOP, and aerobic exercises such as cycling and running can help improve blood circulation to the eyes.”

This content was produced with the assistance of AI translation services.