Friday , May 7 2021

Major Causes of Blindness, Progress of Glaucoma with the Aging Population – 04/27/2019



The main cause of irreversible vision loss, glaucoma will affect 80 million people in 2020 and 111.5 million in 2040, according to forecasts from the World Health Organization (WHO). In Brazil there is a lack of reliable and up-to-date information on the prevalence of the disease, which this year is the main theme of Avril Marom's campaign to prevent and combat various types of blindness.

"What we know is that in recent years there have been more cases because of aging populations and diagnosis than in the past," says Nera Grovina Ogta, an expert on glaucoma in childhood and old age at Clinix Hospital, University of São Paulo (USP) and a member of the Brazilian Council of Ophthalmology (CBO).

What is glaucoma?

This is a chronic and degenerative neurodegenerative disease (a structure that sends the images from the eye to the brain), usually associated with increased intraocular pressure – this indicator indicates eye tension and has an average value of 16 mmHg, but up to 21 mmHg is still considered within the boundary of Normalcy.

This causes a reduction of the field of view, causing the person to gradually lose sight of the periphery. Nara explains that in most cases he is not symptomatic.

"The problem is that when the diagnosis is made, the optic nerve is badly damaged and peripheral vision has already been severely damaged," he said. He says.

Who is affected by the disease?

Pathology has different origins, with genetics being one of the most relevant. To get an idea, children with glaucoma have a 6 to 10-fold chance of developing it.

Advanced age also increases the risks. In general, the incidence of the disease is greater than 40 years, reaching 7.5% in 80, as well as indiscriminate use of corticosteroids without medical follow-up, as they can cause an increase in intraocular pressure.

Attention should also be paid to diabetics, heart patients, trauma or injury victims (for example, a heel or elbow in the eye) and persons of African or Asian origin.

According to Ministry of Health data, the incidence of the disease is three times higher, and the risk of blindness is six times higher among Latins and Afro-descendants than Caucasians.

What types of glaucoma?

There are several types of glaucoma. The most common is primary primary angle, which accounts for approximately 80% of the diagnoses. It is asymptomatic and affects people from the age of 40.

In this case, the intraocular pressure increases slowly due to a malfunction in the eye's drainage angle, which is responsible for the output of the eye fluid (Mimi humor). In general, loss of vision begins at the edges of the visual field, and if not properly treated, ultimately endangers the entire vision.

The closing of the primary angle, with a higher incidence of Asians and people with farsightedness, occurs when the exit angle of aqueous humor is blocked, usually by iris, and the fluid can not be drained.

In general, it causes a sudden increase in intraocular pressure, and the patient may have severe pain in the eyes and head and may blur vision.

Congenital glaucoma occurs when the child is born with a poor structure in the fluid drainage system of the eye. His symptoms include blue eyes, bluish, watery eyes, photophobia and the size of the eyeball. This may be expressed immediately after birth or childhood.

"This is a rare type, but early diagnosis is essential," says Wilma Ellis Barbosa, an ophthalmologist, a member of the Council of Ophthalmology in Brazil and president of the Brazilian Glaucoma Society (SBG).

"The test of the little eye (red reflex), mandatory in some cities, is a perfect opportunity for the pediatrician to assess possible eye diseases in infants."

Another type of glaucoma is normal stress. Unlike others, visual nerve damage also occurs without elevated intraocular pressure. Its causes are unknown, but it is known that there is a connection with vascular problems.

There are also secondary, triggered by external factors such as inflammation, trauma and the use of corticosteroids for a prolonged period without indication and medical follow-up; Pigmentation, caused by the obstruction of the drainage angle of the eye by the loose pigment from the iris, and the pseudo peeling, caused by the obstruction of the drainage system of aqueous humor by abnormal fibrillar deposits.

How is the diagnosis performed?

As in most cases they are a type of asymptomatic type, the diagnosis of the disease occurs in routine ophthalmological counseling. On this occasion, says doctor Nara Grovina Ogata, it is necessary that the measurement of intraocular pressure and examination of the eye's cones, analyze the state and functioning of the optic nerve.

"Depending on the case, a number of additional tests may be required, such as computerized tomography (visual field defects assessment), vocal ultrasound (corneal thickness), optical coherence tomography (retinal examination) "He adds.

It is worth noting that people over the age of 40 and those with a family history of glaucoma should see their ophthalmologist more often. In the assessment, the risk factors will be considered and visitation periods will be determined.

What are the treatment options?

After diagnosed glaucoma, treatment is given according to stage type. Wilma Ellis Barboza, of SBG, stresses that he has no cure, but, yes, control.

"This is a chronic and progressive disease, and the goal of the treatment, whatever it is, is to stabilize it, but it will not cause the patient to return the sight lost, but even in advanced cases, when there is a large loss of vision, , He says.

Treatments are done with clinical, surgical or a combination of the two procedures. With the onset of the disease, it is recommended to use daily application of specific eye drops.

Among the most common are: prostaglandin analogues (travoprost, bimatoprosta and latanoprost), beta blockers (maleol timateol), anhydrase carbon inhibitors (dorzolamide hydrochloride) and adrenergic receptor agonists (bimonidine timonrate). They can be used separately or in combination.

In some situations laser use is also necessary. The first steps of glaucoma angle closure, for example, are performed in this way. Surgery, in turn, is marked by about 10% of cases and congenital glaucoma.

According to the SBG president, adherence to treatment, which is continuous and without a predetermined duration, is very important for its success. "Because they do not understand the evolution of the disease, many patients tend to neglect the supply of drugs," he adds.

Recent studies on glaucoma

Recently, experts from the Brazilian Council of Ophthalmology have promoted two studies on the effects of glaucoma on driving a vehicle to ascertain whether a visual impairment caused by the disease increases the risk of accidents.

In the first month, the effect of density (agglomeration) was assessed – a phenomenon in which the objects mingle when shown very close, making visualization difficult – in glawcomatous.

"The density sets a basic limit to peripheral vision and is essential to explain performance across a wide range of daily tasks," explains Nara, one of the authors of the article.

"And because of the effects of glaucoma on seeing the periphery, we hypothesized that nerve loss in the disease would lead to stronger effects of visual density, which was confirmed," he adds.

At the end of the experiment, published in the February issue of Ophthalmology Research and Visual Sciences (IOVS), The Association for the Study of Vision and Ophthalmology (Arvo), it was found that those who had the disease, even in the early stages, find it more difficult to distinguish between the items.

The second study by the Brazilian Council of Ophthalmology assessed the ability to divide attention by driving and talking on the cell phone, a very common scene of everyday, although prohibited by the Brazilian Traffic Code (CTB). The goal was to examine the performance of glaucoma patients in this condition.

The conclusion was that the response time to visual visual stimuli was more significant in patients with glaucoma. Using the phone, it was 1.86 seconds, compared to 1.14 seconds of drivers with healthy eyes.

Those with the disease should not drive a car, but caution should be given that the risk of accidents is greater, and together with the doctor decide whether to stop or continue this activity.

This work by the Brazilian Council of Ophthalmology was presented at the recent Congress of the American Glaucoma Society in New York, USA, and published this month in the scientific journal What?of American Medical Association (AMA).

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