Glaucoma

Glaucoma summary

Glaucoma is a group of diseases characterized by damage to the optic nerve that causes vision loss. High ocular pressure usually, but not always, causes glaucoma. It is the second cause of blindness in the world, with almost 1 million people affected in Brazil.
The causes of glaucoma are still not fully known, but it is known that the main triggering factor is the abnormal increase in intraocular pressure. This increase may be due to factors such as trauma, diabetes, factors related to ethnicity and age. There are several types of glaucoma, such as acute, chronic, secondary, etc.

Chronic glaucoma is usually an insidious disease without significant symptoms and therefore dangerous. In acute glaucoma, some symptoms that may appear are eye pain, headache, eye redness and dilated pupil. The diagnosis is made by measuring the internal pressure of the eye and with tests that measure the state of the optic nerve, corneal thickness and visual field.

The main complication of glaucoma is permanent and irreversible blindness.

Treatment is done with eye drops and tries to reduce the production of aqueous humor inside the eye or increase the drainage of this liquid. Other approaches are surgery and the use of oral medications.

To control glaucoma, it is important to follow the treatment correctly and apply the eye drops at the indicated times. It is also important to make regular appointments with the ophthalmologist and to exercise constantly.

Definition

Glaucoma is an eye condition characterized by increased intraocular pressure and irreversible damage to the optic nerve that causes vision loss. Increased intraocular pressure usually, but not always, causes glaucoma. To be more precise, glaucoma is a group of eye diseases. In other words, there are several forms of glaucoma.

In fact, intraocular fluid (aqueous humor) is difficult to eliminate. This strong pressure on the eye deteriorates the ophthalmic nerve and over time can lead to blindness.

The term glaucoma comes from the Greek glaukos which means blue-green or gray.

There are different types of glaucoma, which is why, sometimes, glaucomas are also spoken of in the plural (a group of diseases): acute, chronic, congenital and secondary glaucoma.

Glaucoma usually strikes people over the age of 40, however, it can also occur in younger people and in children.

Women are more affected by glaucoma than men, but it is usually more severe in men.

There are several treatments for glaucoma: eye drops, laser, surgery.

Epidemiology

In Brazil, it is estimated that 985,000 people suffer from glaucoma.

In Europe, 9.5 million people suffer from the disease, which is responsible for 20% of cases of blindness in the European Union.1.

A large proportion of these people do not know they have the disease, so it is important to consult an ophthalmologist periodically.

Glaucoma has caused blindness in 7 million people worldwide. Currently 120 million people suffer from glaucoma.

It is estimated that between 1 and 2% of people over 40 years of age have glaucoma, a rate that rises to 10% among those over 70 years of age. It is necessary to know that half of the people affected by this disease ignore it.

Causes

Although the exact causes of glaucoma often remain unknown, the aggravating factors of glaucoma are known, such as:

– heredity (genetic factor, such as cases of glaucoma in the family)

– the “race” or ethnic origin (African and Asian people are more affected than white people)

– to diabetes

– age (risk increases with age)

Glaucoma is caused by increased pressure in the eye. Intraocular pressure increases due to a difficulty of the aqueous humor (intraocular fluid) to flow.

In addition to diabetes, certain diseases such as heart disorders, hypertension and thyroid disorders such as hypothyroidism.

There are different forms of glaucoma, with different origins:

acute glaucoma

In case of acute glaucoma, the intraocular pressure increases sharply, as there is a blockage of the aqueous humor outflow, through the closure of the iridocorneal angle. If no treatment is adopted, blindness may occur in the next few days. It is usually an acute angle-closure glaucoma (rare).

chronic glaucoma

Chronic glaucoma is a disease in which the increase in pressure occurs progressively over the years. It is caused by slowing down the outflow of aqueous humor. Optic nerve damage occurs slowly, and in the long term, if left untreated, glaucoma can lead to blindness. It is usually an acute open-angle glaucoma (common).

congenital glaucoma

This type of glaucoma affects children in their first months. It occurs because of a membrane formed in the iridocorneal angle, which prevents the aqueous humor from being eliminated.

secondary glaucoma

Secondary glaucoma is caused by hypertension in the ocular region after various eye conditions, retinal detachment, thrombosis of the central retinal vein, tumors, trauma.

low pressure glaucoma

A disease not yet fully understood is glaucoma with low intraocular pressure values. In this form, the optic nerve is injured without the eye pressure being elevated.

pigmentary glaucoma

This form of glaucoma develops in young people and adults and is associated with the scattering of pigment granules throughout the eye. These granules can interfere with the drainage of aqueous humor and cause the pressure to rise.

Glaucoma risk groups

As we saw in ” causes of glaucoma “, people at greater risk of developing glaucoma are:

– people who have a relative with glaucoma (heredity)

– Afro-descendants

– the diabetics

– people over 40 years old

– women around 50 years old (acute glaucoma)

– people who have suffered an eye injury, such as impact and speed sports practitioners

– people with high intraocular pressure. We emphasize that an increase in intraocular pressure does not always correspond to glaucoma.

Symptoms

Symptoms differ depending on the type of glaucoma:

Symptoms of Acute Glaucoma

– severe pain in the eye that radiates throughout the head

– headaches (sometimes)

– Red eye

– cloudy cornea

– dilated pupil (in mydriasis)

– hardening of the eyeball

chronic glaucoma symptoms

Chronic glaucoma is an insidious disease, at first little or not at all characteristic (we speak of an asymptomatic disease).

Then there is a narrowing of peripheral vision (almost always imperceptible phase) which triggers (in the absence of treatment) a narrowing of central vision. At this stage, the patient has the impression of seeing through a keyhole or a tube. And if the disease progresses, vision may even disappear, we speak of blindness.

Attention, vision loss due to glaucoma is irreversible!

Only a medical diagnosis can detect the disease.

Diagnosis

The diagnosis of glaucoma in general is performed exclusively by the ophthalmologist. Eye exams for glaucoma include measuring eye pressure.

Tonometry
Intraocular pressure should be measured, usually by tonometry. In this eye pressure measurement test, the ophthalmologist anesthetizes the cornea with the help of anesthetic drops. The examination, thanks to a tonometer that slightly flattens the cornea, lasts only a few seconds or minutes and turns out to be painless, even if it is a little unpleasant. Currently, laser measurements are also available.

When to repeat the exam?
If the eye pressure measurement at the first check is normal, another measurement after 3 to 5 years is sufficient, according to an article published in November 2019 in the scientific pharmaceutical journal Astrea Pharmacie , which quoted a professor of ophthalmology at Winterthur (cantonal hospital ) in Switzerland. On the other hand, if in the measurement, the pressure is at the limit, it is necessary to check again after 1 or 2 years, also according to the article published in Astrea Pharmacie.

Visual field
Another test to assess whether a patient has glaucoma is the visual field test or perimetry. In this exam, the doctor checks the field of vision to analyze low vision or blindness.

Pachymetry Pachymetry
is also a diagnostic tool that measures the thickness of the cornea. This test is important because it allows taking into account the thickness of a patient’s cornea and adapting it to the results of intraocular pressure measured by tonometry. In fact, a thick cornea naturally causes slightly higher pressure. The doctor may think of glaucoma (false positive), while the patient does not have this disease. On the other hand, a patient with a thin cornea may have normal pressure (by tonometry) but still have glaucoma (false negative).

Optic Nerve
Another test in the evaluation of glaucoma is to check the condition of the optic nerve. The doctor, using specific devices, will check whether or not there is damage to the nerve fibers and monitor the evolution.

Consultation after age 40 – Screening
– It is essential to see your ophthalmologist every year after age 40 to perform glaucoma control. In fact, as already seen in the Symptoms section , chronic glaucoma has few characteristic signs and, therefore, it is impossible to diagnose this disease on your own.
– A sore eye, accompanied or not by severe headaches , nausea and vomiting , requires an emergency consultation to treat a possible acute glaucoma as soon as possible.

Complications

Untreated glaucoma, whatever its type, can lead to blindness. This may occur within a few days in the case of acute glaucoma. Patients with untreated chronic glaucoma can lose sight within ten years.

Attention, the loss of vision caused by glaucoma is irreversible!

It is also important to know that glaucoma is in fact the biggest cause of irreversible blindness in the West. In the first place is the cataract , but this disease is easily operated on and the patient can regain vision, in the case of glaucoma, unfortunately, the loss is still irreversible.

When to see a doctor?

It is always advisable to consult a doctor in case of glaucoma (see symptoms of glaucoma).

If the following symptoms are observed, it is necessary to consult a doctor immediately:

– severe eye pain

– blurred vision

– headaches, nausea and vomiting

Treatments

Treatment of chronic glaucoma (open-angle glaucoma)

Nowadays (2022), eye drops or otic solutions for external use can effectively treat open-angle glaucoma by significantly reducing intraocular pressure. This means that taking oral pills (eg acetazolamide) or having an operation is quite rare.

Note on administering eye drops (in drops):
– In general, all eye drops should be administered as a single drop, as the average volume of a drop is greater than the capacity of the eyelid to hold liquid. A second drop only eliminates the first, can increase systemic absorption and double the cost of treatment.2 .
– In case of instillation of a 2nd drop, it must be performed after an interval of at least 5 minutes.

Once the diagnosis of chronic glaucoma has been made, the ophthalmologist may prescribe medications such as:

– prostaglandin analogs : these molecules increase the flow of aqueous humor, the fluid that fills a part of the eye. Examples of prostaglandins: bimatoprost, latanoprost, travoprost or tafluprost. Latanoprost, the first prostaglandin analogue on the market, is often considered the gold standard. Latanoprost, as well as other prostaglandin analogues, can be used for glaucoma alone or in combination with other drugs that lower intraocular pressure, such as timolol (a beta blocker).
Prostaglandin analogues are the drugs of choice for the initial treatment of open-angle glaucoma3.

– beta blockers : these molecules reduce the production of aqueous humor. Examples: timolol, betaxolol, metipranolol, levobunolol or carteolol (Arteoptic®). Beta-blockers can be combined with a prostaglandin analogue (eg latanoprost and timolol).

– alpha agonists or α2-adrenergic receptor agonists (in English: alpha agonists ): they reduce the production of aqueous humor and increase drainage. Examples: apraclonidine, brimonidine

– carbonic anhydrase inhibitors (in English: carbonic anhydrae inhibitors ): these compounds reduce the production of aqueous humor. Examples: dorzolamide, brinzolamide, acetazolamide and methazolamide. Carbonic anhydrase inhibitors may have some systemic side effects4 . In general, the use of oral medications is indicated if the eye drops are not very effective.

– cholinergic agonists : these molecules increase the drainage of aqueous humor. Examples: pilocarpine, carbachol.

– Rho kinase inhibitor . Netarsudil, sold among others under the brand name Rhopressa in the United States, is a glaucoma medication used in the form of a 0.02% ophthalmic solution to reduce elevated intraocular pressure in people with open-angle glaucoma and ocular hypertension. The European Medicines Agency (EMA) approved it in 2019 for the same uses under the brand name Rhokiinsa.

– epinephrine derivatives: these molecules increase the drainage of aqueous humor. Example: dipivephrine.

Note: the doctor may also prescribe a combination of the various molecules mentioned above.

Surgery

– a surgical intervention when there are progressive changes in the visual field.

There are different surgical techniques:

– Laser surgery (these treatments improve the aqueous humor evacuation system of the eye).

– Surgery by filtration.

– Insertion of a drainage implant.

Through surgery, the doctor will allow the aqueous humor to flow by making a slit in the iridocorneal angle.

As seen above, a low-energy laser called selective laser trabeculoplasty (SLT ) can be effective. This laser therapy takes place in a doctor’s office and lasts only a few minutes. In some cases, people with newly diagnosed mild-to-moderate open-angle glaucoma may skip the eye drop phase and opt for SLT.5 . It is important to know that the effects of SLT wear off after three to five years. When this happens, you will likely need to do the procedure again or use eye drops.

Treatment of acute glaucoma by angle closure (narrow or angle closure glaucoma)

The treatment of acute glaucoma is an emergency treatment. It consists of:
1. Procaine injections.
2. Very frequent instillations of pilocarpine (eye drops), every quarter of an hour.
3. Administration of acetazolamide, a drug that decreases watery secretion.
4. A surgical intervention if the glaucoma is not cured by previous measures after 3 days.

Treatment of congenital glaucoma

As noted in the causes of glaucoma, congenital glaucoma occurs at an early age, due to a membrane (Barkan’s membrane) formed in the iridocorneal angle.

Treatment consists of surgical removal of this membrane.

Tips

– It is estimated that most patients suffering from glaucoma do not regularly use their medicine (in this case, the eye drops). Because it is a disease with a slow and insidious evolution, there is a temptation not to use eye drops regularly, which is a mistake, because if glaucoma is not correctly treated, it can develop irreversible blindness! For more information about the disease, see a doctor (or pharmacist, for medications).

– Avoid drinking liquids frequently: drink moderate amounts of liquid throughout the day instead of drinking a large amount at once.

– Exercise frequently, as there is evidence that exercise reduces intraocular pressure in some cases of glaucoma (such as pigmentary glaucoma).

– Make regular appointments with the ophthalmologist.

– Avoid the use of corticosteroids.

– The use of a wedge-shaped pillow that keeps the head slightly elevated by about 20 degrees has been shown to be effective in reducing intraocular pressure during sleep6.

Prevention

Annual ophthalmological consultation at:

>people over 40

>diabetics

>people with a family history of glaucoma (heredity)

– Avoid tobacco and coffee consumption, as these two substances can increase eye pressure.

– Control your eye pressure so that it does not turn into glaucoma.

– Wear eye protection, as eye injuries can trigger glaucoma.

– Adopt a healthy life: reduce stress, eat well, sleep well, etc. We know that diet plays a particularly important role. While a healthy diet won’t stop glaucoma from getting worse, as the Mayo Clinic explains , several vitamins and nutrients are important for eye health, including zinc, copper, selenium, and the antioxidant vitamins A, C, and E.
Plus, exercise regular can reduce eye pressure in open-angle glaucoma.

Jeanne Kenney
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I’m a stylist trainer, a content creator, and an entrepreneur passion. Virgo sign and Pisces ascendant, I move easily between my dreams, the crazy world I want, and my feet on the ground to carry out my projects.

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