What is Glaucoma?

Glaucoma is an eye disease affecting the optic nerve, causing a sharp increase in pressure that can lead to progressive vision loss. In the affected eye, the outflow of aqueous humor is obstructed. Fluid accumulates, and intraocular pressure increases, compressing the optic nerve and damaging nerve fibers. Optic nerve damage results in progressive visual field alteration, narrowing until complete vision loss. If undiagnosed, this disorder causes irreversible visual damage.

Symptoms of Glaucoma

Glaucoma symptoms vary considerably depending on disease progression and can mimic other conditions like brain tumors.

Generally, both eyes are involved (though one may be more severely affected).

Slowly progressing glaucoma initially has no symptoms. Months or years later, symptoms may appear as spots obscuring vision, starting at the edges of the visual field and gradually expanding. Headaches, malaise, and eye redness may also occur. Untreated, vision loss becomes complete, leading to blindness. These types of glaucoma are painless.

Acute angle-closure glaucoma, conversely, presents with immediate symptoms lasting one to two hours before subsiding. Each episode reduces vision further, necessitating urgent medical attention. Symptoms of acute angle-closure glaucoma include:

• Intense eye and surrounding pain;
• Headaches;
• Nausea and vomiting;
• Red eye;
• Seeing colored rings around lights;
• Blurred vision;

Diagnosis and Screening for Glaucoma

Visual Field Examination

The operator measures peripheral vision using an instrument presenting light stimuli around the eyes.

Tonometry

Tonometry measures eye pressure. The doctor anesthetizes the eye (with analgesic eye drops) and uses a tonometer – an instrument gently placed on the eye or using an air puff (air tonometer) to measure intraocular pressure. This is painless and harmless. Normal intraocular pressure is 11-21 millimeters of mercury (mmHg). Higher values suggest glaucoma, though other causes exist.

Evaluation of the Optic Nerve by Ophthalmoscope, Slit Lamp or OCT

The ophthalmologist evaluates the optic nerve using pupil-dilating eye drops and instruments for detailed visualization. The ophthalmoscope and slit lamp allow magnified observation of the optic nerve using lights illuminating the eye's back. Optical Coherence Tomography (OCT) captures images of the optic disc for visualization and comparison over time. Angio-OCT detects abnormalities in eye blood vessels.

Gonioscopy

Gonioscopy analyzes the trabeculum (the area between the iris and cornea where aqueous humor circulates) involved in glaucoma. A special lens allows the doctor to observe and detect abnormalities.

Corneal Measurement

The doctor measures corneal thickness. Thin corneas increase the likelihood of glaucoma, but don't necessarily indicate its presence.

Treatment of Glaucoma

Treatment of Secondary Glaucoma

Secondary glaucoma treatment addresses the underlying cause. Infections are treated with antibiotics, antivirals, or antifungals; inflammation with corticosteroids. Simultaneous cataracts and glaucoma necessitate urgent cataract surgery, sometimes resolving the glaucoma as well.

Treatment of Open-Angle Glaucoma

Open-angle glaucoma is initially treated with eye drops, often lifelong, to control intraocular pressure. Common medications include beta-blockers, prostaglandin analogs, alpha-adrenergic agonists, or carbonic anhydrase inhibitors. Regular check-ups are essential. If medication is ineffective, causes side effects, or lesions are too advanced, surgery may be necessary.

Treatment of Acute Angle-Closure Glaucoma

Acute angle-closure glaucoma requires urgent intervention with potent, fast-acting drugs to quickly lower intraocular pressure, possibly including acetazolamide and diuretics. Surgery follows on both eyes, even if symptoms are in only one, due to the high likelihood of bilateral involvement.

Surgical Treatment of Glaucoma

Several surgical options exist for glaucoma. These are generally safe, often allowing same-day discharge:

• Argon Laser Surgery: Eye drops anesthetize the eye's surface before laser enlargement of drainage holes (laser trabeculoplasty) or creation of new ones in the iris (laser peripheral iridotomy). This safe, painless, brief procedure (minutes) is often outpatient. Initial intraocular pressure increase may necessitate short-term eye drops;
• Trabeculectomy: Creates a new opening to facilitate aqueous humor circulation. This filtering surgery requires sedation or general anesthesia. Complications (bleeding, infection, hypotension, trauma) are rare and manageable;

Living with Glaucoma

Ophthalmologists are researching gene therapy to repair optic nerve damage and potentially reverse glaucoma-induced blindness. Currently, this is experimental. Meanwhile, individuals with glaucoma can take steps to lower intraocular pressure and manage treatment-related difficulties, such as glare from eye drops.