Open Angle Glaucoma

Description of Glaucoma

Glaucoma is a progressive optic neuropathy, an eye disease characterized by damage to the optic nerve and retina (the retina receives visual information from the environment and transmits it to the optic nerve) cells. Glaucoma is divided into 3 forms: congenital, open-angle, closed-angle.

Open-angle glaucoma can be congenital, primary, secondary. Risk factors for developing it:

heredity, race (it occurs earlier and more severely in black people), age, concomitant diseases such as diabetes or arterial hypertension, as well as eye circulation disorders, eye refractive errors (myopia). The disease develops when nerve fibers and retinal cells responsible for transmitting visual information to the optic nerve die due to intraocular pressure. Intraocular pressure may increase due to changes in the drainage system, when fluid drainage is disrupted (Schlemm’s canal blockages, changes in the trabecular meshwork and collector channels).

Symptoms

The disease starts in individuals over 40 years old, it is often asymptomatic for many years, affecting both eyes. One day, vision worsens suddenly or is completely lost. Only a few people experience symptoms before the onset of the disease – sometimes there is a recurring dull pain in the eye, temple area, above the eyebrow, tearing, seeing colored rings when looking at a light source, narrowing of the visual field.

After several years of the disease, atrophy (wasting) of the optic nerve and retinal cells occurs. In this case, the visual field narrows, the person sees spots in the field of vision (scotomas), as the disease progresses, vision weakens until complete blindness.

Diagnosis

An eye doctor performs ophthalmoscopy – examination of the fundus of the eye, gonioscopy – inspection of the angle of the anterior chamber. They also measure intraocular pressure and visual field.

Treatment

Primary glaucoma is treated with medications that reduce eye pressure: beta-adrenergic blockers (Timolol maleate), carbonic anhydrase inhibitors (locally – dorzolamide), systemic diuretics (Diacarb), prostaglandins (latanoprost), adrenergic agonists (clonidine), parasympathomimetics (pilocarpine).

Surgical treatment is applied when medications are ineffective, vision worsens, and the visual field narrows. New pathways for fluid to drain from the chambers are created.

If intraocular pressure is elevated but there are no changes in the fundus of the eye and visual field, surgery is not performed.

Patients with glaucoma must follow a specific regimen:

avoid work with the head down and in the dark, avoid alcohol and smoking, limit fluid intake to 1.5l/day, eat a more dairy and plant-based diet, take prescribed medications.

Source | Author Doctor Nikas Samuolis, reviewed by Prof. Virginijus Šapoka | Vilnius University | Faculty of Medicine | Head of the Department of Internal Medicine, Family Medicine, and Oncology