Glaucoma: the silent thief of sight

Glaucoma is a disease of the optic nerve, the cable that connects the eye’s camera to the brain. When this cable is damaged, the images captured by the retina no longer reach the visual centers correctly, and a portion of the visual field switches off slowly, progressively, and silently. This is exactly why it is known as “the silent thief of sight”: it steals portions of the world without the patient noticing.

In simple terms, the eyes are balls under pressure. Inside the eye, a fluid called aqueous humor is continuously produced and must drain away steadily; when this balance is disrupted and drainage slows down, internal pressure rises and compresses the fibers of the optic nerve until they wear away. However, elevated pressure is not the only culprit: there are forms of glaucoma that develop even with apparently normal pressure values.

Why it is so insidious

Typically, chronic glaucoma causes no pain or blurred vision in its early stages. The damage begins at the periphery of the visual field and moves toward the center, so the patient continues to see well “straight ahead” and does not notice the scotomas, the portions of the visual field that are no longer perceived. It is a bit like looking at the world through a tube that narrows year after year. By the time symptoms become evident, unfortunately, the damage to the optic nerve is already advanced and this is the crucial point – irreversible.

As a rough estimate, glaucoma is thought to affect around 2-3% of the population over the age of forty, and a significant proportion of those affected are unaware they have it. It is one of the leading causes of irreversible blindness worldwide, which explains why prevention holds such particular value for this disease.

The progressive loss of optic nerve fibers over time, faster in glaucoma patients.

Diagnosis

The good news is that today we have highly sophisticated technology to detect glaucoma long before the patient notices anything. Measuring eye pressure (tonometry) is only the first step. The visual field test (perimetry) records any portions of vision that may have been lost, while OCT (optical coherence tomography) measures the thickness of the nerve fibers around the optic nerve with micrometric precision, revealing early damage years before symptoms appear. These are complemented by assessment of the drainage angle (gonioscopy) and measurement of corneal thickness.

Treatment

The goal of treatment is not to cure damage that has already occurred cannot be recovered but to halt progression by lowering the internal pressure of the eye. In most cases, treatment begins with pressure-lowering eye drops, instilled daily, which reduce the production of aqueous humor or improve its drainage. When drops are not enough or are not well tolerated, it is possible to turn to laser treatment (trabeculoplasty) or surgery, which today is increasingly minimally invasive. In any case, a glaucoma patient must be monitored over time: treatment is measured and adjusted visit after visit.

Early diagnosis: the real challenge

However, as we have seen, the real challenge of glaucoma is early diagnosis. Because the disease gives no warning signs until the damage is significant, the only truly effective tool is a periodic eye exam, particularly after the age of forty, and even more so in the presence of a family history, since having a parent or sibling with glaucoma carries a significantly higher risk. A simple exam, including tonometry and OCT, can catch the disease while it is still completely silent and it is precisely in that silence that the chance to preserve excellent visual function for a lifetime is decided.