Glaucoma – the main cause of blindness

15. August 2014

Glaucoma is the chronic neuropathy of the optic nerve that causes damage to the nerve fibres of the optic nerve and ganglion cells. This disease is the leading cause of blindness in the world.

Ophthalmologist at East-Tallinn Central Hospital Pille Tein says the disease is characterised by scotomas, concentric constriction of the field of vision and, in the late stages, reduction of visual acuity until total loss of vision in the eye. The disease often causes an increase in intraocular pressure, which is the main risk factor in the development of the neuropathy of the optic nerve. Other risk factor are age – eye pressure usually increases after the age of 60 – local and systemic vascular factors and genetic predisposition. Long-term use of steroids, especially eye drops, can increase the secondary risk of glaucoma. This is why patients who use eye drops based on dexamethasone (e.g. for allergic conjunctivitis) should have their eye pressure checked twice a year.

“Glaucoma is also called the ‘small thief of vision’, as it often causes no pain or noticeable changes in vision and has no symptoms in its early stages,” says Tein. “This means that glaucoma progresses slowly, until irreversible damage has been caused.”

The most common forms of glaucoma are open-angle and angle-closure glaucoma, and eye pressure may also increase as a result of other eye diseases (diabetic retinopathy and uveitis) or developmental disorder syndromes.

The symptoms of glaucoma are eye pain or headache in the region of the forehead or eyebrows, usually on the side where the eye has been damaged; pressure or tension in the eye; halos or circles in front of the eyes or seeing rainbow-coloured rings; light sensitivity; blurred vision (periodic or constant); and acute attacks of glaucoma can cause severe eye pain and headaches in the forehead region which may radiate into the arms as well as nausea and vomiting.

Diagnosing glaucoma starts with a routine eye check or determination of visual acuity and correction with glasses. Glaucoma can also be diagnosed by studying the eyes with a biomicroscope or a slit lamp or by examining the ocular fundus with an ophthalmoscope: assessment of the status of the optic disc and nerve fibres; measuring eye pressure (tonometry); measuring the thickness of the cornea (pachymetry), which is related to eye pressure; examining the iridocorneal angle with a special goniolens (gonioscopy); and testing fields of vision with static or kinetic perimetry. Qualitative examination of the optic disc may also be used to support the process of diagnosis: optical coherence tomography (OCT), Heidelberg retinal tomography (HRT) and scanning laser polarimetry (GDX).

Tein says the objective of glaucoma treatment is to maintain the patient’s existing quality of life, which is closely related to the preservation of the visual function and field of vision. Today, glaucoma is treated by lowering intraocular pressure, which is still the only efficient method of treatment. Reducing the pressure by 1 mm Hg decreases the progress of glaucoma by 20%. Diagnosing glaucoma is usually followed by medicinal treatment, which may be associated with laser treatment and then surgical treatment.

As glaucoma is a long-term progressive disease that often requires the use of topical treatment and regular visits to the doctor, the patient’s constant cooperation with the doctor is essential for successful treatment of the disease. Glaucoma may be kept under control, but unfortunately it cannot be cured. Early diagnosis and treatment help slow the progress of damage to the optic nerve and preserve the existing functions for a longer period.

The inpatient treatment facilities and operating theatres of the Eye Department of East-Tallinn Central Hospital are located in the Ravi Unit, while the Outpatient Eye Clinic sees patients in the Ravi and Magdalena units.

Call 1900 for information and registration.