The term Glaucoma covers a group of degenerative disorders causing damage to the optical nerve and the vision field. In 2/3 of the cases the changes are due to increased intraocular pressure and in 1/3 of the cases it is caused by blood vessel changes.
The individual norm is different for every patient. Intraocular pressure which does not bring any risk for damaging the optic nerve and the vision field is considered normal. Usually the normal range is between 10 and 20 mm Hg although in some conditions such as glaucoma with a damaged optical nerve and other factors like atherosclerosis, diabetes, etc, it is necessary to keep IOP below 18 mm Hg to stop progression of glaucoma damage.
When glaucoma manifests after birth it is congenital or childhood glaucoma. The most common type of glaucoma, which is not caused by other eye diseases, occurs after the age of 35 and is known as primary glaucoma. If glaucoma is caused by other diseases such as inflammation, changes in the lens, injuries, etc, it is called secondary glaucoma.
This is the most common type of glaucoma. It occurs when the eye drainage canals are clogged. The intraocular pressure (IOP) increases because the intraocular fluid cannot flow out of the eye in the normal way. In this type of glaucoma the entrances to the drainage canals are clear and they should be functioning properly. However, clogging appears inside the drainage canals like the clog that builds up in the drain pipe of your kitchen sink.
Angle-Closure Glaucoma This type of glaucoma is also known as acute glaucoma or narrow-angle glaucoma. It is not so common and what makes it different from the open-angle glaucoma is the fact that the intraocular pressure increases very rapidly. This occurs when the drainage canals are clogged or blocked. In angle-closure glaucoma the iris and cornea are not as wide or open as they should be. The exterior edge of the iris covers the drainage canals when the pupil is dilated too much or too quickly. This can happen, for example, when you enter into a dark room from bright light.
Glaucoma is a disease which if not treated leads to blindness as a result of cell death and damage to the optic nerve. Blindness is irreversible because the optic nerve dies and cannot be restored.
A leading risk factor for the optical nerve damage is the increased intraocular pressure. Other factors are: very low blood pressure, short-sightedness, diabetes, decreased blood flow to the optic nerve and the combination of all of these factors. The risk is 8 times higher if you have an immediate family member with glaucoma. Glaucoma can occur at any age but is more common in people over 45.
Patients suffering from glaucoma have no symptoms and for a long time they do not realize that they are losing their sight. Visual acuity is preserved for a long period while in the mean time the damage to the optic nerve progresses. The patient realizes the vision problems when 40% of the optic nerve has died and that is the advanced stage of the disease. Therefore, regular eye tests are very important. Early diagnostics of the disease and timely treatment can save your vision.
Depending on its type, glaucoma can develop without any symptoms, similarly to the cataract, without pain and other signs except for decrease in vision and narrowing of the peripheral vision or it can start with a rapid increase of the intraocular pressure. This is accompanied by pain in the eye, the temple and headache, blurred vision, poor eyesight, coloured rings, nausea and vomiting. If glaucoma is not treated the damage to the optic nerve and the vision field is irreversible and leads to blindness.
These include: observation of the anterior eye segment, measuring of intraocular pressure, visualisation of the optic nerve with an ophthalmoscope, examination of nerve fibre layer (HRT and OCT), visual field exam (perimetry) and chamber angle examination (gonioscopy).
The aim of treatment is through medication, laser intervention and surgery, to lower the intraocular pressure and stop the progression of glaucoma.
Surgery is recommended when medications do not achieve the desired level of intraocular pressure and glaucoma progresses.
Glaucoma surgery restores the natural drainage of the eye by creating a new drainage pathway for the free flow of fluid or by reducing the production of fluid. 80-90% of glaucoma surgeries are successful. They do not result in a better vision but help preserve it in its current state. Any surgery carries a small risk of complications like bleeding, inflammations, too low postoperative intraocular pressure, clouded lens and others but they are incomparable with the risk of irreversible loss of vision.
After trabeculectomy the intraocular fluid is drained through a fistula and forms a bleb under the conjunctiva of the upper eyelid which can cause a feeling of irritation. Patients should have good hygiene and apply anti-inflammatory drops and ointments. Only early disease detection and timely treatment can maintain vision in patients with glaucoma.
Glaucoma is the second leading reason for blindness globally. More than 4 million people around the world have lost their vision due to glaucoma. In many cases it develops without any symptoms and is diagnosed too late. More than half of the patients are unaware of the disease and do not get any treatment. If the disease is found and treated on time vision can be saved. At the beginning of March every year you can have a free examination of your eyes: do not miss it!
EX-PRESS™ Glaucoma Filtration Device is a small device with the size of a rice grain which is implanted between the inner region and the outer region of the eye. EX-PRESS ® Glaucoma Filtration Device ensures proper functioning of the drainage system of the eye which was damaged by glaucoma.