Glaucoma – causes, symptoms, treatment. Glaucoma prophylaxis

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Glaucoma is a disease that damages the optic nerve, gradually causing deterioration and loss of vision. Unfortunately, glaucoma usually develops slowly and is asymptomatic for a long time. So let’s find out how glaucoma develops and who is at risk of it.

How does glaucoma damage the optic nerve?

In a healthy eye, clear, aqueous fluid circulates inside the anterior chamber of the eye. For the eye to function properly, an adequate amount of aqueous humor must be maintained in the chamber to provide adequate pressure. The correct pressure is maintained thanks to the continuous inflow and outflow of liquid from the chamber. With glaucoma, the flow of the aqueous humor is disturbed, the fluid accumulates, the pressure inside the eye rises, which gradually damages the optic nerve.

See also: Structure of the eye – functions, the process of seeing

Glaucoma – causes

High pressure in the eyeball has always been considered the cause of glaucoma, but its origins may vary. Among people who are particularly exposed to glaucoma, we can mention:

1. diabetics,
2. people suffering from atherosclerosis and hyperlipidemia,
3. nearsighted people in whom the defect is below 4 diopters and is accompanied by changes in the retina and the choroid of the eye,
4. people with a family history of glaucoma,
5. people particularly exposed to stress,
6. migraineurs,
7. people over 60 (black people over 40),
8. people after an eye injury,
9. people who have had eye surgery before,
10. people taking corticosteroid medications (especially in the form of eye drops),
11. people who have problems with high blood pressure.

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See also: The myopia epidemic is coming. Find out how you can avoid the disease

Glaucoma – types

There are several types of glaucoma, depending on the causes and course of the disease.

Types of glaucoma – primary open angle glaucoma

Primary open angle glaucoma – This is the most common type of glaucoma. This type of glaucoma occurs because the special structures responsible for the drainage of the aqueous humor stop working properly, causing the aqueous humor to become trapped in the eye and the pressure inside the eyeball increasing.

This type of glaucoma develops slowly and gives no symptoms for a very long time, or the symptoms are so subtle that, ironically, you simply don’t notice them. Most often, the patient goes to the doctor with a very high degree of nerve damage, when the field of view is narrowed to approx. 50%.

It is also worth noting that the intraocular pressure, which is the main indicator of a doctor’s suspicion of glaucoma, may fluctuate and it often happens that the measured pressure is within the normal range at a given moment. Therefore, for a proper diagnosis, the doctor should also examine our optic nerve.

Types of glaucoma – glaucoma with normal intraocular pressure

Normal intraocular pressure glaucoma is a type of glaucoma that occurs despite normal (repeatedly measured) eye pressure. Although the pressure values ​​are similar to that of healthy people, there is nerve damage and a gradual loss of vision.

Types of glaucoma – angle-closure glaucoma

This type of glaucoma progresses in people who close the channel where the aqueous fluid flows out of the eye. If the channel is completely closed, the so-called an acute attack of glaucoma, accompanied by: very high pressure in the eye, headache, irritability of the eyeball, nausea and vomiting. In the event of an acute attack of glaucoma, you should immediately see a doctor or the emergency room.

Types of glaucoma – secondary glaucoma

Secondary glaucoma is caused by another eye disease, such as an eye injury, long-term steroid use or cancer.

Types of glaucoma – congenital glaucoma

Congenital glaucoma is the rarest type of glaucoma and is most likely hereditary. This glaucoma develops in infants and young children. Unlike other types of glaucoma, this type of glaucoma most often leads to complete blindness.

See also: The blind man partially regained his sight after 40 years. The effects of the new therapy are promising

Glaucoma and visual field defects

Loss of visual field can occur due to many diseases or disorders of the eye, optic nerve, or brain. In the eye, for example, glaucoma causes peripheral field defects. Macular degeneration and other macular diseases cause defects in the central field. Damage to the visual pathway causes characteristic forms of visual impairment, including homonymous hemispheric vision, quadrantanopsy, and scotoma.

The main classification of visual field defects includes:

1. eye retinal damage (heteronymous field defects in glaucoma and AMD);
2. optic nerve injuries (heteronymous field defects);
3. damage to the optic junction (e.g., binaural amblyopia, side vision loss).

In glaucoma, visual field defects result from damage to the layer of nerve fibers in the retina. Field defects are mainly visible in primary open-angle glaucoma. Due to the unique anatomy of the RNFL, many noticeable patterns are visible in the field of view.

These are the common disadvantages of the glaucoma field

1. Generalized visual field defect: Occurs in the early stages of glaucoma and many other conditions. Mild narrowing of the central and peripheral visual field caused by isopter contraction turns into a generalized visual field defect. If all isopters show a similar depression at the same point, this is called visual field shortening. Relative paracentral scotomas are areas where smaller and darker targets are not visualized by the patient. You can see bigger and brighter targets. In normal tension glaucoma (NTG), small medial depressions, mainly transnasal, are observed. The generalized depression of the entire field is also visible in the cataract.
2. Baring of the blind spot: means the exclusion of the blind spot from the center field due to the internal curvature of the outer 30 ° boundary of the center field. It is only an early nonspecific change in the field of vision, with little diagnostic value in glaucoma.
3. Bjerrum’s Arched Frost: The small scotoma in the Bjerrum area is the earliest clinically significant field defect observed in glaucoma. Dots may be visible above or below the blind spot.
4. Mroczek Siedla: The paracentral Mroczek connects with the blind spot, creating the Seidel sign.
5. Rönny’s step: formed when two arched scotomas run in different arcs, creating a cavity at right angles. This is also seen in the advanced stages of glaucoma.
6. Peripheral field defects: Peripheral field defects can occur in the early or late stages of glaucoma.
7. Tubular vision: Since macular fibers are most resistant to glaucoma damage, central vision remains unchanged until the final stages of glaucoma. Spotting or tunnel vision is the loss of peripheral vision while maintaining central vision, resulting in a narrowing of the field of vision that resembles a circular tunnel. This is seen in the final stages of glaucoma. Retinitis pigmentosa is another disease that causes spotting vision.
8. Temporal Isle of Vision: It is also seen in the final stages of glaucoma. The temporal islets lie outside the central field of view from 24 to 30 °, so they may not be visible with standard central field measurements made in glaucoma.

Also check: Visual field examination

Glaucoma – the most common symptoms

A follow-up consultation with a doctor once a year or two is very important because the symptoms of glaucoma are in many cases weak and ignored. It is worth contacting a doctor when the following symptoms appear:

1. seeing the so-called halo around light sources,
2. decreased vision,
3. redness of the eye
4. blurry iris of the eye, especially in newborns,
5. nausea or vomiting
6. cause of
7. narrowing of the field of view (so-called tunnel vision).

Glaucoma causes the bundles of visual fibers within thirty degrees from the center of the fundus to be damaged and a spot to appear in their place. Man has a lot of nerve fibers in the eye, which is why their slow atrophy is often imperceptible. For many years, many people are unaware that they have glaucoma. In the final stage of the disease, patients see the image around them as “through a keyhole”. Light, contours, some movement are noticeable, the eyes are actually blind. Glaucoma can cause complete blindness.

Also check: Dark spots in front of my eyes. What do they show and how to fight them?

The diagnosis of glaucoma

In order for a doctor to correctly diagnose glaucoma, he must take into account the characteristic changes in the appearance of the optic nerve disc and defects in the visual field. In the diagnosis of glaucoma, a very wide range of examinations is used, in which, in addition to the analysis of visual acuity at a distance and close, also include other aspects. You can make an appointment with an ophthalmologist via the halodoctor.pl portal. During the visit, the doctor will collect an interview and provide information on further procedures.

1. Fundus examination: thanks to it, it is possible to determine if there are any anatomical damages in the area of ​​the optic nerve in the course of glaucoma.
2. Imaging examination to assess the condition of the optic nerve and the layer of nerve fibers: performed with modern equipment that precisely determines the advancement level of glaucoma and whether the optic nerves have been damaged by it. In Poland, this equipment is available, for example, in glaucoma clinics, so patients can control the development of the disease and the effectiveness of treatment. It is not enough to achieve low pressure inside the eye. Glaucoma imaging can be performed using the following methods: glaucoma tomography, optical fundus coherence tomography (OCT), SD OCT (new generation optical tomography), GDx (illustrates the thickness of the layers of nerve fibers).
3. Visual field test: This is one of the basic glaucoma tests that use computer programs. The examination precisely analyzes the field of view within thirty degrees from the center. This analysis should be repeated at least once a year, as it also allows you to monitor the effectiveness of treatment and the possible progression of the disease.
4. Measurement of intraocular pressure: this test is performed with the use of special tonometers: Tonometer, “Computer” tonometer, Goldmann applanation tonometer, Dynamic Contour Tonometer.
5. Angle of drainage test: This test observes the natural outflow path of the aqueous humor. This is done using a very high magnification and lighting with a slit lamp. The study classifies the types of open eye glaucoma. In open-angle glaucoma you can see the beginning of the outflow tract, i.e. trabecular glaucoma, while in closed-angle glaucoma you will not see it. The examination of the angle of filtration is helpful in diagnosing the primary closure of the angle of filtration, which is due to the anatomy of the eye, and the secondary closure, which is due to other conditions.
6. Imaging of the anterior segment of the eye with optical tomography: helps to recognize what is the mechanism of angle closure in a given eye. Thanks to this examination, the doctor is able to adjust the appropriate therapy. Treatment consists of correcting the existing eye corner to open the natural drainage path and prevent it from closing. Another procedure (for occlusive eye closure) is to create an artificial outflow of aqueous humor.

All results of imaging tests should be kept (do not throw away!) As they are the basis of any consultation with a doctor, but also useful when, for example, we move to another city and change the doctor (glaucoma is a lifelong disease and requires treatment for the rest of our lives) .

In the diagnosis of glaucoma, the most important are diagnostic tests. Don’t wait, buy a glaucoma diagnostic test package. The package includes both an ophthalmological consultation and the necessary tests necessary to diagnose glaucoma.

Glaucoma epidemiology

There is a belief that glaucoma is a disease that mainly affects the elderly, but it can also occur in young people – unfortunately it often goes undiagnosed. The risk of glaucoma increases with age. In people aged 40-50, glaucoma occurs in 0,5% of cases. In the following years, the risk of the disease increases up to 5%, and the greatest risk exists in people over 60 years of age (respectively 70 -80 years – almost 10%). In fact, half of those affected by glaucoma are unaware of the disease and live with it for many long years. The symptoms of glaucoma are tricky and therefore often unnoticeable.

See also: What is epidemiology?

Glaucoma – treatment

Glaucoma can be treated in several ways depending on the severity and type of glaucoma. The main treatment is the use of eye drops (anti-glaucoma). Glaucoma drops lower the pressure in the eye in two ways: by inhibiting the secretion of aqueous humor or by increasing the flow of fluid so that it can drain freely. Glaucoma drops are strong medications and have many side effects, including: allergies, eye redness, severe burning and eye irritation, blurred vision.

Surgical treatment is the last resort and consists in allowing the aqueous humor to drain out of the anterior chamber of the eye. You should not use the eye drops more than once or twice a day as they have a long-lasting effect.

The group of anti-glaucoma drugs includes:

1. Prostaglandins: facilitate the drainage of aqueous humor from the eye and lower the intraocular pressure, have an effect of over 24 hours.
2. Pilocarpine: This drug was invented over a century ago and is used in acute angle closure attacks and before laser treatments.
3. Beta-blockers: cause less aqueous humor to come out of the eye and lower intraocular pressure by up to 25%. For beta-blockers, the last dose should be taken at least two hours before bedtime.
4. Carbonic Anhydrase Inhibitors and Sympathomimetics: Their action is similar to beta-blockers, they also reduce the amount of aqueous humor and the pressure in the eye.

See also: Prostaglandins and their application in medicine

When using anti-glaucoma drops, proper technique is important for the medicine to work properly. The active substances contained in the preparation must penetrate well into the eye. When instilling the eyes, do not drip the drug into the inner corner and blink to distribute the drug. Why? Blinking causes the so-called a tear pump, which sucks the drops into the tear duct, so as a consequence they have no chance of getting into the eye.

Attention! Glaucoma is a disease that cannot be cured, but it can only be stopped at an early stage to prevent damage to the optic nerve. In the treatment of glaucoma, it is also possible to perform procedures aimed at correcting the anatomical condition of the eye.

Glaucoma treatment – laser treatments

Laser treatment uses a strong beam of light to improve the drainage of fluid from the eye. While the laser may complement your eye drop use, it may not completely replace them. The results of laser treatments vary but can last up to five years. Some laser treatments can also be repeated.

There are two main types of laser surgery to treat glaucoma. They help drain water from the eye. These procedures are usually performed in an ophthalmologist’s office or outpatient clinic.

The most popular method is peripheral iridoplasty (iris modeling), aimed at correcting the configuration of the flat iris. This procedure consists in flattening the steep slope of the iris and pulling its base away from the trabeculae. Thanks to the use of iridoplasty, the narrow slit of the percolation angle becomes wide open.

Iridotomy, on the other hand, like the previously discussed procedure, is aimed at people with primary angle-closure glaucoma. It involves making a small hole in the peripheral part of the iris (usually in the upper part of the eyeball). The opening creates an additional path of fluid flow between the posterior and anterior chamber of the eyeball. The treatment enhances the greater part of the trabecular structure and restores the more physiological anatomical system in the eye.

Glaucoma treatment – surgical treatment

This is another way to reduce eye pressure. It is more invasive, but can also achieve better eye pressure control faster than drops or a laser. Surgery can help slow vision loss, but it cannot restore lost vision or cure glaucoma. There are many types of glaucoma surgery, and depending on the specific type and severity, your eye doctor may choose one of them.

Kanaloplastyka – is a non-penetrating procedure using microcatheter technology. To perform a canaloplasty, an incision is made in the eye to access Schlemm’s canal in a manner similar to a viscocanalostomy. A microcatheter will circle the canal around the iris, enlarging the main drainage canal and its smaller collecting canals by injecting a sterile, gel-like material called viscoelastic. The catheter is then removed and the suture is placed into the canal and tightened.

Trabeculectomy — the most common conventional surgery performed for glaucoma is trabeculectomy. In this case, a partial thickness flap is made in the scleral wall of the eye and an opening is made under the flap to remove part of the trabecular mesh. The scleral flap is then loosely sutured back in place to allow fluid from the eye to drain through the opening, which lowers the intraocular pressure and creates a fluid bubble at the surface of the eye. There may be scarring around or above the opening, making it less effective or losing its effectiveness altogether. Traditionally, chemotherapeutic adjuvants such as mitomycin C (MMC) or 5-fluorouracil (5-FU) are applied to the wound bed with soaked sponges to prevent scarring of filtering follicles by inhibiting fibroblast proliferation. Contemporary alternatives to prevent scarring of the mesh opening include the sole or combined use of non-chemotherapeutic adjuvants, such as the Ologen collagen matrix, which has been clinically shown to increase the success rates of surgical treatment.

Glaucoma drainage implants – Over the years, many implants for glaucoma drainage have been developed, including the Baerveldt implant or valve implants such as the Ahmed valve implant or the ExPress Mini valve and Molteno implants. They are indicated for glaucoma patients who do not respond to medical therapy after an unsuccessful trabeculectomy procedure. A flow tube is inserted into the anterior chamber of the eye and a plate is implanted under the conjunctiva to allow the watery fluid to flow out of the eye into a chamber called a follicle. The first generation of Molteno implants and other valveless implants sometimes require the tube to be ligated until the follicle formed is slightly fibrotic and watertight. This is to reduce postoperative hypotension – sudden drops in postoperative intraocular pressure. Valve implants, such as the Ahmed valve, attempt to control postoperative hypotension with a mechanical valve.

Laser assisted deep sclerectomy – The most popular surgical approach currently used to treat glaucoma is trabeculectomy, in which the sclera is punctured to relieve intraocular pressure. A similar, but modified procedure is nonpenetrating deep sclerectomy (NPDS), in which, instead of puncturing the sclera bed and trabecular mesh under the sclera flap, a second deep scleral flap is formed, it is excised along with further Schlemm’s canal uncorking, on which it is obtained oozing of fluid from the inner eye, thereby relieving intraocular pressure, without penetrating the eye. NPDS has been shown to have significantly fewer side effects than trabeculectomy. However, NPDS is done by hand and requires a higher level of skill that can be assisted with tools. To prevent adhesion of wounds after a deep sclera resection and to maintain good filtering results, NPDS, as with other non-penetrating procedures, is sometimes performed using a variety of biocompatible spacers or devices.

Laser assisted NPDS is performed using a CO2 laser. The laser-based system completes itself when the required sclera thickness is achieved and the intraocular fluid is drained properly. This self-regulating effect is achieved because the CO2 laser essentially ceases to ablate as soon as it comes into contact with the soaked intraocular fluid, which occurs as soon as the laser reaches an optimal residual thickness of the intact layer.

Lens extraction In people with chronic angle-closure glaucoma, lens extraction can remove the blockage created by the pupil and help regulate intraocular pressure.

Glaucoma – prognosis

In open angle glaucoma, the typical progression from normal vision to total blindness takes about 25 to 70 years without treatment, depending on the method of assessment used. Intraocular pressure can also be affected, with higher pressure reducing the time to blindness.

Can Glaucoma Be Cured Completely?

It certainly cannot be cured glaucoma primary open angle (JPOK). This type of glaucoma is an idiopathic condition whose genetic cause and other factors are not fully known. Treatment in this case lasts until death, and is mainly based on inhibiting the progression of glaucoma, so that the patient can have reasonably good eyesight for the rest of his life.

Why is the treatment ineffective? This may be due to:

1. too late a diagnosis of glaucoma. The symptoms of the disease are the more difficult to recognize the more developed the damage to the optic nerve;
2. not taking medication or skipping doses, avoiding eye check-ups. Patients often ignore the recommendations because glaucoma sometimes does not indicate its presence at all, they do not feel pain, they do not feel any deterioration of their eyesight.

However, it can be cured primary angle glaucoma (JPZK). This type of glaucoma is caused by our eye’s anatomical structure, which is recognizable by optical tomography of the anterior segment of the eye. Thanks to this, the mechanism of closing the angle can be determined, and the doctor can choose the right method of laser or surgical treatment. This method introduced a revolution in the diagnosis of primary angle-closure glaucoma and its treatment, which allows the opening of the natural outflow pathway for watery pleas.

The possibility of eliminating the cause of the disease, both existing (treatment) and threatening (prophylaxis), is a big positive that can now be offered to patients exposed to the risk of vision loss in the so-called “Acute attack of glaucoma.” Unfortunately, this does not mean that the effects of glaucoma will recede if it previously led to optic neuropathy,

Glaucoma – research

Glaucoma and Rho Kinase Inhibitors

Rho kinase inhibitors, such as ripasudil, act by inhibiting the actin cytoskeleton, causing morphological changes in the trabecular meshwork and increased water drainage. More compounds in this class are being tested in Phase 2 and Phase 3.

Glaucoma and neuroprotective agents

A 2013 Cochrane systematic review compared the effects of brimonidine and timolol on slowing the progression of open-angle glaucoma in adult participants. The results showed that participants assigned to brimonidine showed less visual field progression than those assigned to timolol, although the results were not significant given the large loss of follow-up and limited evidence. Mean intraocular pressures in both groups were similar. Participants in the brimonidine group had a higher incidence of drug-induced side effects than participants in the timolol group.

Glaucoma and cannabis

Research in the 70s showed that cannabis use can lower intraocular pressure. In order to determine whether marijuana or drugs derived from it could be effective in the treatment of glaucoma, the US National Eye Institute supported research in 1978-1984. These studies have shown that some marijuana derivatives reduce intraocular pressure when administered orally and intravenously, or by smoking, but not when applied topically to the eye. In 2003, the American Academy of Ophthalmology (AAO) issued a statement stating that cannabis is no more effective than prescription drugs.

Moreover, no scientific evidence has been found to demonstrate an increased benefit and / or reduced risk of cannabis use in the treatment of glaucoma compared to the wide range of pharmaceuticals available today. In 2010, the American Glaucoma Society published a position that discredited the use of cannabis as a valid treatment for elevated intraocular pressure, for reasons ranging from short duration of action and side effects that limit many activities of daily living.

Also check: Legal cannabis – for health and beauty

Glaucoma – prevention

Here are some practical tips to help you avoid glaucoma.

1. Glaucoma runs in families, so do not forget about preventive examinations.
2. Early diagnosis of primary angle closure protects you from developing glaucoma and acute attacks that can cause permanent loss of vision.
3. Surgical correction of anatomical features that pose a risk of glaucoma is an effective way to prevent the disease from developing.
4. Preventive examinations should be accompanied by the selection of appropriate glasses for close-up work, it is especially necessary for people over 40 years of age. Glasses should be replaced every 2 years.
5. In addition to the intraocular pressure, the optic nerve should also be examined, as well as the front part of the eye with gonioscopy.