Glaucoma - A silent disease that can cause blindness
It's important to know that glaucoma is the third most common cause of blindness worldwide, after cataracts and trachoma.
Glaucoma is a chronic and silent eye disease which, if left untreated, can lead to permanent vision loss and even blindness. The term "glaucoma" derives from the Greek word γλαύκωμα (Glaucose) used since 400 years before Christ, and which essentially described a greenish tinge to the pupil, very different from the normal color.
When we talk about glaucoma, we are talking about a group of signs characterized by high intraocular pressure, associated with damage to the optic nerve and visual field loss. However, it was discovered that a good number of cases, commonly known as low-tension glaucoma, showed definite evidence of damage to the optic nerve and alterations in the visual fields, despite having a normal intraocular pressure. Thus, in addition to high IOP, several other factors, such as inadequate blood supply to retinal ganglion cells and optic nerve fibers due to atherosclerosis or advanced age-related connective tissue changes, are believed to play an important role in the progression of glaucoma. This possible vasculogenic theory has led to talk of a "vascular optic neuropathy".
It's important to know that glaucoma is the third most common cause of blindness worldwide, after cataracts and trachoma. But when it comes to causes of irreversible blindness, glaucoma is the first cause. It's even more important to know that in the vast majority of cases vision loss and blindness could have been avoided.
It is estimated that there are around 70 million people with glaucoma worldwide. Of these, around 7 million are blind in one eye and around 1 million are blind in both eyes. In around 20% of cases, patients go blind before they have access to diagnosis or treatment. Portugal has around 200,000 people with glaucoma, half of whom don't know they have the disease. The prevalence of glaucoma increases with age. Between the ages of 40 and 49, it's around 1%, but rises to 3% between 60 and 69. After 70, it's 5%. Apart from age, there are other risk factors. A family history of glaucoma, African or Hispanic race, high myopia, diabetes, high blood pressure and the use of corticosteroids increase the risk of glaucoma.
Glaucoma prevention mainly involves early detection and appropriate treatment. Regular eye examinations are essential, especially for people with risk factors. Diagnosis of glaucoma by an ophthalmologist usually involves a combination of intraocular pressure measurements, evaluation of the optic nerve and visual fields. It should be noted that the most common form of glaucoma - open-angle glaucoma - can go on without any symptoms until a very advanced stage of the disease. At that point, the loss of vision and visual field is irreversible. This is why glaucoma is often referred to as "the silent thief of sight". It's very important for people to see their eye doctor regularly, especially after the age of 40.
Treatment for glaucoma usually begins with eye drops, which help to lower intraocular pressure. In rare cases, oral medication may be prescribed. In more advanced situations or when medication is not effective, it may be necessary to resort to laser surgery or conventional surgery to reduce intraocular pressure. It's important not to stop taking the drops because in their absence the glaucoma continues to progress without the person having any symptoms. It is also important for the person with glaucoma to make sure that the drops are being placed correctly. Often the lack of efficacy has to do with poor placement. The drops should be placed in the lower conjunctival sac of the affected eye (the conjunctival sac is the area between the lower eyelid and the eyeball). To apply the drops correctly, the person tilts their head back slightly, gently pulls the lower eyelid to create a small space (the fundus of the conjunctival sac) and applies the drop into this space. You should avoid touching the tip of the bottle to your eyes or eyelids to avoid contamination. It is advisable to keep your hand holding the lower eyelid so that it remains away from the eyeball for another minute or two after placing the drop so that it is completely absorbed. It is also important to use the drops the number of times a day indicated by the doctor and to leave an interval of around 5 minutes between drops.
Although there is currently no cure for glaucoma, advances in early detection, more effective treatments and a better understanding of the disease offer hope for a future where vision loss due to glaucoma is minimized. Awareness, education and access to proper eye care are crucial to achieving this goal.
Source: "Observer", March 2023.