Glaucoma covers a group of diseases that affect the optic nerve, usually in a chronic and progressive way. This pathology arises due to the difficulty in draining a liquid naturally produced in the eye, called aqueous humor, and causes an accelerated loss of nerve fibers, which can lead to significant and irreversible defects in the patient’s vision.
It is a disease with a major impact on the world population. According to the WHO, this is the second most common cause of blindness in the world, and the main cause of irreversible blindness. In 2020, the number of patients with glaucoma was 76 million and is estimated to grow, reaching 112 million in 2040. In Portugal, data points to approximately 100 thousand patients with glaucoma, 6 thousand of whom are already considered blind.
Primary open-angle glaucoma is the most common form of all glaucomas. There is also primary angle closure glaucoma, in which the aqueous humor drainage area becomes narrower. This type is more prevalent in the Asian population. In addition to primary glaucomas, there are secondary glaucomas, which arise due to eye trauma, inflammatory eye diseases or corticosteroid treatments.
Most cases of open-angle glaucoma do not present any symptoms until the most advanced stages of the disease, which is why glaucoma is known as the “silent thief of vision”. In cases of angle narrowing glaucoma, patients may present symptoms at an early stage: intense eye pain, headache and nausea, red eyes, blurred vision and colored halos. In the presence of these symptoms, the patient must be urgently evaluated by an ophthalmologist, due to the risk of developing blindness in a short period of time, if not treated in a timely manner.
Half of glaucoma patients are undiagnosed
Several studies have shown that at least half of glaucoma patients are not diagnosed and that a large proportion of cases are diagnosed at an advanced stage of the disease. Since the damage it causes to the optic nerve is irreversible, early diagnosis and appropriate treatment are essential to mitigate the impact of glaucoma on the patient’s quality of life. To this end, regular follow-up at an ophthalmology consultation is important.
Glaucoma screening should always be carried out by an ophthalmologist and is recommended for patients over 40 years of age, or earlier if there are risk factors. Some risk factors for open-angle glaucoma are increased intraocular pressure, advanced age, being of African descent, having a family history of glaucoma, high myopia and a thin cornea. Risk factors for angle closure glaucoma are advanced age, being female, being of Asian ethnicity, having hyperopia and eyes with reduced axial length.
The ophthalmological examination of these patients should include measurement of intraocular pressure, observation of the optic nerve and assessment of the aqueous humor drainage angle. It is often complemented by measuring the field of vision of each eye, structural analysis of the optic nerve using optical coherence tomography (OCT), and determining the thickness of the cornea.
Glaucoma has no cure, but it can be treated. Currently, the only effective therapeutic approach is to reduce intraocular pressure to values that stabilize the progression of the disease, through the application of eye drops, laser treatment or surgery. For glaucoma treatment to be fully effective, it must be started before serious damage to the optic nerve occurs. It is for this reason that an early diagnosis by an ophthalmologist is essential.
An article by Teresa Gomes, Maria Reina and Mariana Cardoso, ophthalmologists at CUF Descupadas Hospital
