Glaucoma is an eye disease that is actually related to irreversible damage to the optic nerve that leads to progressive vision loss and blindness. In most cases it is caused by an increase in intraocular pressure (the pressure inside the eye), something that has nothing to do with blood pressure.
Glaucoma usually evolves without symptoms so, since it does not cause discomfort, the person suffering from it can consult a doctor when it is too late.
Glaucoma usually affects both eyes, although it can be more severe in one than the other. It represents the second cause of blindness in the world after cataracts.
What are the causes of glaucoma?
Glaucoma is more frequent at advanced ages and has a certain hereditary component. The main cause of glaucoma is increased pressure inside the eye (intraocular pressure). Under normal conditions, intraocular pressure remains stable as there is a balance between the production of aqueous humor and its elimination.
The aqueous humor is a liquid produced by the eye that is responsible for nourishing the cornea and lens and providing the necessary pressure to maintain the spherical shape of the eyeball. When its production increases or its output is difficult, it can increase intraocular pressure.
Sometimes glaucoma is caused by an obstruction of the channel through which the aqueous humor is eliminated.(located between the iris and the cornea), which is called closed-angle glaucoma. Cause or consequence of another disease:
- Hereditary (they are the most frequent cause).
- Eye trauma.
- Serious eye infections.
- Blockage of the blood vessels of the eye.
- Inflammatory diseases of the eye.
- In case of complications for previous eye surgery.
The increased pressure maintained over time can injure the eyeball at its weakest point, which is the area where the optic nerve exits, compressing and damaging the nerve cells. Depending on the number of damaged nerve cells, more or less vision is lost. When the destruction is complete, blindness ensues.
What types of glaucoma exist?
There are various types of glaucoma. Its differentiation is important in terms of prognosis and treatment:
- Open angle glaucoma. It is the most frequent glaucoma in developed countries. Although there are no abnormalities in the structure of the eye that would lead to suspicion of an obstruction, the aqueous humor is usually not eliminated correctly.
- Closed or narrow angle glaucoma. The space between the iris and the cornea (front chamber of the eye) is smaller than normal so there is less room for fluid to be at that level. As a consequence, it is difficult for the aqueous humor to pass into the anterior chamber, increasing the pressure behind the iris. The iris is therefore pushed forward, obstructing the exit angle of the aqueous humor. When the outlet angle is completely blocked, an acute glaucoma attack occurs.
- Normal tension glaucoma. It may be due to a decreased blood supply to the optic nerve or other factors that cause nerve cell death.
- Congenital glaucoma. It is due to the defective development of the drainage channels of the eye during the period before birth. Children are born with a defect that decreases the elimination of aqueous humor.
- secondary glaucoma. It is due to an obvious cause that has led to said complication, such as the presence of cataracts, previous eye surgeries, treatment with corticosteroids, eye drops that dilate the pupils, etc.
Who is at risk for this disease?
Glaucoma affects more than 3 out of every 100 people in the population and can appear at any age, being more frequent in:
- Over 45 years old.
- People who have relatives with glaucoma.
- People with elevated intraocular pressure.
- Subjects with severe high-grade myopia.
- People with diabetes (both type 1 diabetes mellitus and type 2 diabetes mellitus).
- Subjects receiving treatment with oral corticosteroids.
- People with high blood pressure.
- If there are previous eye injuries.
- Descendants of African American, Irish, Russian, Japanese, Hispanic, Eskimo, or Scandinavian.
What are the symptoms of glaucoma?
Most glaucoma patients have no symptoms. The first sign is usually loss of vision in the lateral areas of the visual field. Depending on the severity of the elevation of intraocular pressure, vision can be lost in a period of between 2 and 5 years.
Children with congenital glaucoma often have cloudy eyes, high sensitivity to light, and excessive tearing.
Occasionally, in angle-closure glaucoma, eye pressure can rise sharply, leading to an acute glaucoma attack.
Acute glaucoma is characterized by:
- Stabbing eye pain spread to the entire eye socket (“nail pain”).
- Diminished vision.
- Light intolerance.
- Involuntary closure of the eyelids.
- Red eye.
- Dilated pupils.
- Headache, nausea and vomiting.
In acute glaucoma, the pressure of the eyeball through the upper eyelid produces a sensation of great hardness, as if it were made of marble, with intraocular pressure usually being greater than 40 mmHg.
Sometimes there are previous signs that “warn” of the proximity of an acute glaucoma attack (vision of colored halos around lights, blurred vision, eye pain in the dark, pain in the area where the attack is going to occur) .
Acute glaucoma is a medical emergency that requires hospital admission and immediate treatment to prevent irreversible vision loss that can occur after one or two days.