Glaucoma (or glaucoma) is an eye condition in which the optic nerve is damaged and often leads to blindness.
This nerve is located at the back of the eye.
In most cases, damage to the optic nerve is caused by an increase in
How does glaucoma develop? Why does eye pressure increase?
The eye consists of two parts:
- The posterior area between the lens of the eye and the optical lens
- The anterior area, which is located between the lens and the cornea and which is divided into:
- Anterior chamber that includes the iris, pupil and cornea
- Posterior chamber, consisting of ciliary body and lens.
The aqueous humor is a liquid produced by the ciliary body, which serves to:
- To give shape and volume to the eye,
- To provide the eye with nutrients.
The aqueous humor flows from the ciliary body to the pupil.
It then circulates between the iris and the cornea (anterior chamber) to form a trabecular scaffold that acts as a filter for the aqueous humor.
This fluid must leave the eye via Schlemm’s canal, which leads to the veins of the sclera.
The balance between aqueous humor flowing from the ciliary body and the one flowing away again makes it possible to maintain a pressure between 10 and 21 mmHg.
Types of glaucoma
In chronic open-angle glaucoma (also called chronic glaucoma or primary open-angle glaucoma), there is a partial blockage (block) at the level of the cornea-scleral trabecular meshwork (resorption channel of the aqueous humor).
The reason why the trabecular meshwork is clogged and does not allow the circulation of aqueous humor is not fully understood.
The aqueous humor accumulates when the outflow is too small, and the excess fluid increases intraocular pressure.
There is a normal angle between the iris and the cornea.
The increase in pressure in the eye can damage the following structures:
- The optic nerve (the main nerve for vision)
- Nerve fibers that run from the retina to this nerve
The retina contains cells that receive light stimuli and convert them into nerve signals that are sent to the brain.
It is located in the back of the eye.
The damaged parts of the retina and nerve cause:
- Permanent spots in the field of vision
- Vision loss
In some cases, complete blindness may occur.
The nerve suffers from the pressure acting on it, and in advanced stages, the optic nerve papilla becomes atrophic and takes the form of a “bulge”.
Open-angle glaucoma is the most common type.
It develops slowly, possible damage to the optic nerve and loss of vision occur gradually.
In angle-closure glaucoma:
- The angle between the iris and the cornea is reduced (less than 20°)
- The space for the aqueous humor is too narrow, so fluid accumulates in the anterior chamber
- The iris can be pressed against the lens
- Chronic angle-closure glaucoma leads to a sudden increase in intraocular pressure
- The eye turns red very quickly and hurts
Secondary glaucoma is caused by various pathologies that lead to an increase in eye pressure.
For example, it can occur as a complication in:
- Some eye injuries
- Taking corticosteroids
Congenital glaucoma is a disease that exists from birth.
Neovascular glaucoma is characterized by the formation of fibrous tissue and new blood vessels in the area of the ventricular angle and trabecular meshwork.
If an eye problem leads to a reduction in blood flow, the cornea forms new blood vessels to prevent cell death of the retina.
Usually, this type of glaucoma is caused by:
The result is a reduced outflow of aqueous humor to the veins of the sclera.
Pigmentary glaucoma is characterized by abrasion of the iris tissue that contains a pigment (dye) to absorb excessive light.
The result is a displacement of iris fragments, which can reach the trabecular meshwork and clog it.
In pigmentary glaucoma, the trabecular meshwork is pigmented.
Pseudoexfoliation glaucoma is a particularly severe type of open-angle glaucoma.
It is characterized by erosions on the front surface of the lens caused by friction with the iris skin.
The material ejected from the lens can clog the trabecular meshwork.
Glaucoma can affect both eyes (bilateral). However, it progresses faster in one eye than in the other.
What is the difference between increasing eye pressure and glaucoma?
Glaucoma means that part of the optic nerve is damaged by the increase in eye pressure.
However, about 20% of people with glaucoma have normal eye pressure.
In this case, one speaks of normal pressure glaucoma, the optic nerve can be damaged even at a relatively low pressure.
Other factors, such as decreased blood outflow, can lead to atrophy of nerve tissue.
In contrast, some people have increased eye pressure, but no glaucoma and also no loss of vision.
However, if the eye pressure is increased, there is a much higher risk of developing glaucoma and thus loss of vision.
Who is affected by chronic open-angle glaucoma?
About 2% of people over the age of 40 have glaucoma.
In people over the age of 75, this figure rises to about 1 in 10 people.
Only rarely do young people under the age of 35 have glaucoma.
Risk factors include:
- Familial accumulation of glaucoma
- Ethnicity, as people of African or Afro-Caribbean origin are more affected because they have a slightly different form of eye structure
- Myopia and hypermetropia, in this case the anterior chamber of the eye is flatter
- Cataract, because the lens can increase volume and hinder the flow of aqueous humor
- Taking corticosteroids
What are the symptoms of chronic open-angle glaucoma?
As a rule, there are no symptoms in the first stages of the disease.
Most people with glaucoma don’t notice any problems until there is a slight loss of vision.
- The first part where vision loss occurs is the outer area (peripheral) of the visual field.
- Central vision, which is used when concentrating on an object, such as reading, is maintained until an advanced phase of the disease.
Blindness can be prevented. When glaucoma is detected and treated early.
Symptoms of angle-closure glaucoma
- Eye pain – an important symptom for diagnosis. A patient who arrives at the emergency medical service with eye pain must suspect glaucoma
- Reddened eyes
- Nausea and vomiting (for this reason, it is sometimes thought to be a digestive disorder)
- Limited field of view (tunnel vision) where central parts of the field of view are clear but edges are black
- Occurrence of halos around light sources
- Mydriasis (pupil dilation).
Diagnosis of glaucoma and examinations
The doctor must proceed as follows:
- Collection of medical history
- The eye examination usually involves a detailed examination with an instrument called a slit lamp.
- Examination of the fundus – the posterior part of the eye, where the optic nerve (the so-called papilla) exits, is examined
- There are certain changes that can be seen in this area when someone has glaucoma
- Tonometry – to also measure the pressure in the eye (intraocular pressure)
- Pachymetry – measurement of corneal thickness
- This value is important because the thickness of the cornea has an influence on the accuracy of intraocular pressure measurement.
- Also, people with a thinner cornea are more likely to develop glaucoma
- Gonioscopy – a special lens can be used to examine the area of the drainage (or trabecular meshwork) of the eye
- Visual field examination. This examination is important to determine the field of vision while looking straight ahead
- In glaucoma in the early stages, the periphery (outer side) of the visual field is usually affected
- OCT (optical coherence tomography) – an innovative device for examining the retina and macula.
Who Should Get Screened for Glaucoma?
All people over the age of 35-40 should have their eyes examined by an ophthalmologist every five years.
A check-up every 2-3 years should be carried out at the age of over 50 years.
The eye examinations are particularly important if you belong to one of the above-mentioned
An eye exam can detect glaucoma early, before significant vision loss occurs.
When to worry?
One should immediately visit an emergency room if there is eye pain associated with:
- Reduced vision
In this case, timely intervention by the ophthalmologist can preserve vision.
Not all hospitals can perform surgery for angle-closure glaucoma, so you should consult a specialist.
In open-angle glaucoma, the first symptom is loss of peripheral vision.
The patient becomes aware of this while driving, for example, if he notices too late cars or pedestrians coming from the side streets.
Treatment of chronic open-angle glaucoma
The aim of the treatment is to reduce eye pressure.
However, this treatment cannot restore all the vision that has already been lost.
Eye pressure can be lowered in several ways.
Eye drops for glaucoma
A variety of available eye drops can lower eye pressure.
These drugs are used to:
- Reduce the amount of aqueous humor produced. The drops used are mostly beta-blockers: timolol (timophtal), etc.
- To improve the outflow of aqueous humor, drops with prostaglandin (for example, latanoprost, bimatoprost, travoprost) are used.
The drops work better for some people than others.
For example, beta-blocker drops can not be used in people with:
- Heart disease
In addition, the side effects vary with the different drops.
Contact lenses are not a contraindication in glaucoma, but beta-blockers cause dry eyes. Therefore, in this case, you should wear glasses.
In some cases, two different types of eye drops are required to keep eye pressure low.
Tablets work by decreasing the amount of aqueous humor produced. However, the side effects can be unpleasant. Therefore, tablets are not used so often by patients.
Laser treatment for glaucoma
If eye drops do not satisfactorily reduce pressure, laser treatment may be recommended.
There are two possible laser procedures for open-angle glaucoma, exfoliation glaucoma, or pigmentary glaucoma:
- Argon laser trabeculoplasty (ALT) – allows to widen the openings in the trabecular meshwork to favor the outflow of aqueous humor. The laser causes a burn that destroys some fibers of the trabecular meshwork.
- Selective trabeculoplasty (SLT), a more modern technique that acts only on the pigment cells. Beams with a wavelength of 532 nm are used.
This type of surgery reduces complications and risks.
Before the procedure, anesthetic eye drops are administered.
This treatment lasts only a few minutes and is carried out in a day clinic (the patient is not hospitalized).
A special contact lens is placed on the eye to direct the laser onto the iris.
Trabeculoplasty with the laser does not cause pain.
To lower intraocular pressure, the following are needed:
- 10-15 days for selective trabeculoplasty
- 30-45 days at ALT
When to operate? Surgery for glaucoma
If other methods of treatment are not effective, the surgeon may advise surgery, called a trabeculectomy.
Trabeculectomy consists in the creation of a canal in the anterior region of the eye, just below the conjunctiva.
In this way, the aqueous humor can bypass the clogged trabecular meshwork.
- The operation is painless.
- The procedure is performed under local anesthesia and takes about 2 hours.
- The patient is discharged home the same day and does not have to stay in the hospital.
Postoperative course of trabeculectomy
The patient must wear a bandage on the operated eye for two days.
The first two weeks he has to wear an eye patch at night and sunglasses on sunny days.
Postoperative symptoms include:
- Photophobia (photosensitivity)
- Blurred vision
- Foreign body sensation in the eye
It takes up to 15 days for vision to be restored.
Complications of trabeculectomy include:
- Decreased intraocular pressure
In some cases, a repeat of the operation may be necessary.
This is usually done because scar tissue forms inside the canal and prevents the correct drainage of the ocular humor.
Iridoplasty with laser (argon)
This treatment consists in the use of a laser beam that causes thinning and retraction at the base of the iris skin.
Iridoplasty allows the angle between the iris and cornea to be widened, facilitating the flow of aqueous humor.
The treatment lasts about 15 minutes.
Iridotomy is a surgical procedure used to treat:
- Angle-closure glaucoma
- Iridolenticular block, a condition in which aqueous humor cannot flow from the posterior chamber of the eye to the anterior one
- Acute attack of glaucoma
In this treatment, the surgeon pierces the upper part of the iris (under the eyelid) to create a channel between the posterior and anterior chambers of the eye.
The ophthalmologist can use a Yag or argon laser.
What is the prognosis for glaucoma patients?
Most people who suffer from glaucoma do not completely lose their vision.
However, for the preservation of vision, it is very important to follow the treatment plan prescribed by the doctor.
One should follow the appropriate instructions and use the eye drops regularly.
Prevention of glaucoma
For the prevention of glaucoma, a healthy diet is recommended because:
- Diabetes is a cause of this condition.
- Old age is a significant risk factor and a diet rich in fruits and vegetables and rich in antioxidants can slow down the aging process.
- Loss of vision
- Using natural remedies to treat gastritis
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