Glaucoma | Miranza - Clínica Muiños
What is Glaucoma?
Glaucoma is a frequent disease in our environment and the main cause of preventable blindness in developed countries. Glaucoma is the progressive damage of the optic nerve that we can notice if a progressive change of the visual field occurs and which is usually related to increased intraocular pressure, arterial hypotension or alterations in circulation. If this disease is not treated, it will slowly cause blindness, but if it is diagnosed on time it can be treated and controlled.
This is a disease caused by an increased intraocular pressure up to a level that produces irreversible damage to the optic nerve fibers. These fibers are damaged when the intraocular pressure is greater than the level that varies depending on each individual. If the increased pressure is maintained for some time or if it is quite high, these fibers can be damaged in an irreversible manner. This means, that the loss of eyesight will be irreversible.
When all optic nerve fibers are damaged, the capacity to transmit images to the brain is completely lost, so the individual will become completely blind.
Why does the Intraocular Pressure Increase?
Inside the eye flows a liquid, which is in charge of feeding internal eye structures. This liquid has a function that is similar to blood, but it has the advantage that, since it is completely transparent, it allows the light to pass through it. This allows eyes to accomplish the mission for which they were designed. This liquid called the aqueous humor has production and evacuation systems. The perfect balance between these two systems maintains the intraocular pressure practically constant. But, if due to some malfunction of these mechanisms, more liquid enters than the liquid that leaves the eye, the pressure increases and the optic nerve starts to get damaged.
Types of Glaucoma
Not all glaucomas are alike. Although ophthalmologists are able to diagnose dozens of different glaucomas, based on a practical point of view, we will highlight the following:
- Congenital Glaucoma. It is produced due to a defective development of exit paths of the aqueous humor. In the first weeks or months of life, the child will feel tearing and photophobia (which means that the child cannot keep his/her eyes open when there is light.) The cornea will start losing transparency and will look whitish. At the same time, the eye, due to the increase of internal pressure, will become larger. One must be especially careful with children who have eyes that are bigger than the rest of children of the same age, specifically if light bothers them.
- Closed-Angle Chronic Glaucoma: This type of glaucoma occurs with the sudden closing of aqueous humor elimination pathways. It is the best known one because it appears abruptly with a great deal of pain and with a sudden decrease in eyesight, colored hazes that surround lights and even nausea and vomit, etc. This occurs because, due to the special form of the eye of some persons, the angle through which this liquid must be eliminated is too narrow and it is possible that, in some circumstances, the walls of this angle will contact each other, and will completely obstruct the pathway. Everything that was previously explained brings about the very quick increase of pressure and a very intense pain (nail pain).
- Open-Angle Chronic Glaucoma: This is the most frequent type of all glaucomas, since it corresponds to around three fourths of glaucoma cases that are diagnosed. It is caused by the progressive deterioration of the aqueous humor elimination system that, in a natural manner, is produced when aging, but, in this case, it accelerates until the capacity to maintain a normal of intraocular pressure is lost. The disease appears slowly, without producing symptoms that might be detected by the person who suffers them.
How is Glaucoma Diagnosed?
Periodic ophthalmic exams, which are usually carried out each year to detect glaucoma, include the following ones:
1. Tonometry or measurement of intraocular pressure.
2. Ophthalmoscopy or exam of the back of the eye, to find out if there is some damage to the optic nerve.
3. Gonioscopy to check, in case of suspected glaucoma, which type it belongs to.
4. Campimetry or exploration of the visual field. This exam is not routinely carried out, but it is required to confirm the diagnosis and to decide on an adequate treatment. That is why it is performed when tonometry or ophthalmoscopy make the ophthalmologist suspect that the disease is in its initial stage or if the specialist has doubts and wants to confirm the diagnosis.
The individuals with a greatest risk to suffer from glaucoma are those that have a family history of the disease, elderly individuals, persons who have diabetes, who have been treated for a long time with corticosteroids or who have cardiovascular diseases. Therefore, they must get periodic checkups.