What is glaucoma and how common is it?
Glaucoma is a major disease given its frequency and potential seriousness. Approximately 1.5-2% of over 40s suffer from the condition and this rate increases with age. It is the second most common cause of blindness in this country. Nevertheless, this blindness can be avoided if diagnosed and treated in time.
Glaucoma is a disease of the optic nerve that is usually chronic, progressive and irreversible. It is characterized by loss of visual field, which does not normally have symptoms until the more advanced stages. In most cases it is linked to high eye pressure.
There are some acute forms of glaucoma that show symptoms quickly and are normally accompanied by pain and loss of vision and which are less common. In these, eye pressure rises quickly due to the anatomy of the eye (primary closed-angle glaucoma) or secondary to swelling, trauma or another eye disease.
What causes glaucoma?
There are lots of risk factors that can contribute to the appearance of glaucoma. Amongst them, high eye pressure is the most serious. In most cases, raised eye pressure is the result of difficulty eliminating aqueous humour (the liquid in the eye). Eye pressure is considered normal when it is below 22 mmHg, but some eyes with glaucoma need to maintain lower pressure to prevent the disease from progressing.
Other important factors, such as genetic predisposition or vascular factors also influence to a different degree in each patient.
What can be done to not lose vision due to glaucoma?
Seeking diagnosis in order to prevent consequences. That’s to say, going to the ophthalmologist if you have any of the risk factors listed below (question 4).
Comply with the revisions and treatment recommended by the ophthalmologist.
Recommend to members of your family that they have a medical check up.
Who is at a greater risk of suffering from glaucoma?
- Those over 40 are at greater risk of suffering from the condition. This risk increases as patients get older.
- Those with high eye pressure. This is the main risk factor for developing glaucoma. It is essential to follow any treatment that has been prescribed in order to have the best possible prognosis for the illness.
- Those with a family history of glaucoma. There is between a 4% and 16% risk of developing glaucoma if a close family member (father, mother, sibling) suffers from it.
- Myopia. Those with myopia have approximately double risk of developing glaucoma than the rest of the population.
- Those from certain ethnic backgrounds. Those of African descent have a higher incidence of glaucoma and it tends to present itself earlier and more aggressively.
Those at higher risk of suffering from glaucoma should have an eye exam to rule out the presence of the disease or to enable early diagnosis if present.
Is there more than one type of glaucoma?
There are various types of glaucoma. Amongst the most common are the following:
- Primary open angle glaucoma. This is the most common type. It normally appears after the age of 40. It develops slowly and does not present symptoms until the final stages where it causes loss of vision. It is normally diagnosed in routine check-ups at the ophthalmology consultation.
- Closed-angle glaucoma. It may present in acute or chronic form. The acute form is usually accompanied by intense eye pain, reddening of the eye and blurred vision, which is why most patients go to the emergency services, where the diagnosis is carried out. It is a serious illness, with a high risk of vision loss. For this reason early diagnosis and preventative laser treatment (iridotomies/iridoplasty) can help to avoid it.
- Secondary glaucoma. Heterogenous group of glaucoma. There is a specific cause in these cases, which is often another eye disease, which causes eye pressure to be raised. Amongst these is pigmentary glaucoma, pseudoexfoliative, connected with swelling, secondary to treatment with corticoids, neovascular…
- Congenital glaucoma. This is seen in the first days or months of the patient’s life and is secondary to anomalies in eye development during pregnancy. Specifically, it occurs at the level of the trabecular meshwork (which is where aqueous humour drainage takes place).
How is glaucoma diagnosed?
In acute glaucoma, patients often suffer pain and loss of vision, which is why they normally go to the ophthalmology emergency room, which makes their diagnosis easier with the exams that are described below.
Nevertheless, chronic glaucomas (the most common types) are a slow and silent illness, that does not cause patients discomfort until very advanced stages. Those who suffer are not aware of their illness until very advanced stages. For this reason those who are at greater risk of suffering from the disease should undergo check ups to rule it out and to make possible early diagnosis.
Glaucoma is diagnosed with a complete eye exam, aimed at evaluating intraocular pressure, the state of the optic nerve and its function.
In addition to the general opthalmological exam, the following tests will be carried out:
Tonometry: analysis of intraocular pressure
Campimetry: examination of the visual field
Detailed exam of the pupil and the layer of nerve fibres with a slit lamp. There are currently various instruments that contribute to early diagnosis and monitoring of glaucoma: GDX, OCT and HRT.
Gonioscopy: examination of the drainage angle of the aqueous humour.
Once you have had your consultation and depending on our doctor’s opinion, the relevant tests will be carried out to ensure the appropriate monitoring depending on the type and degree of glaucoma. Chronic glaucoma requires regular check ups for the rest of the patient’s life.
What is the treatment for glaucoma?
The main objective of the treatment is to maintain vision and quality of life for the patient. Treatment is currently aimed at treating the cause in secondary glaucomas and, in all types of glaucoma, reducing eye pressure.
The main treatment is medical and consists of eyedrops. These eyedrops contain different medications that help to reduce intraocular pressure. There are many types of effective eyedrops, but some of them cause mild discomfort when applied (eye reddening, sensation of a foreign body in the eye…). Nevertheless, it is very important to carry out treatment following the instructions indicated by your ophthalmologist. If you do not follow the treatment, the evolution of the disease is worse. Not using drops correctly can put your vision at risk.
Laser treatment is also useful for glaucoma. There are two types:
Trabeculoplasty, suitable for open-angle glaucoma.
Iridotomy (small hole in iris) and iridoplasty (strong impacts that stretch the peripheral iris and open the angle). It is used in closed-angle glaucomas.
Cyclophotocoagulation. This is used in few cases, only in those that do not respond to other medical or surgical treatments.
It should be pointed out that laser treatments are carried out on an outpatient basis.
Surgical treatment is necessary for a considerable number of cases. Generally this is carried out when medical or laser treatments are not enough to control pressure and/or stop the illness from progressing.
The most widely used surgical techniques for treating glaucoma are:
- Deep non-perforating sclerotomy with or without an implant.
- Devices for drainage in the sub-conjunctival space (Ahmed, Baerdvelt, Molteno…)
- Trabecular implants
All of these surgeries are carried out on an out-patient basis, but they require strict postoperative care and a treatment that the patient should carry out at home. The success of the surgery largely depends on the patients following the treatment prescribed by their ophthalmologist.
Can glaucoma cause blindness?
Yes, some types of glaucoma can lead to blindness. In fact, this illness is the second most common cause of blindness in our country. Nevertheless, with the available treatments, in most cases the illness can be controlled.
Dr. Anton, head of the Glaucoma Department, answer some of the more frequent questions.