Glaucoma pathology diseases

2021-02-02 12:00 AM

Glaucoma is one of the leading causes of blindness in our country as well as in the world, if not diagnosed and treated promptly, it can lead to permanent blindness.

Define

A glaucoma is a group of diseases caused by many causes and pathogenesis, but in the full-blown stage, there are 3 typical signs for all forms, these signs are:

Elevated intraocular pressure of 25 mmHg or more.

The vision is narrow.

Eye bottom examination shows signs of disc atrophy.

Epidemiology

Glaucoma is one of the leading causes of blindness in our country as well as in the world, if not diagnosed and treated promptly, it can lead to permanent blindness. 

Primary glaucoma is familial. Family history is considered a significant factor in primary glaucoma. Scientists have identified the genes responsible for primary open-angle glaucoma. In primary angle-closure glaucoma, it is recognized that angle-closure glaucoma can be inherited, but family history does not allow to confirm in the future whether the blood relatives of patients with angle-closure glaucoma will have glaucoma or not.

Glaucoma is an age-related disease, the older the age, the greater the incidence of glaucoma. The disease is common in people over 35 years old.

Angle-closure glaucoma is common in eyes with special structures as follows: small eyes, small cornea, shallow anterior chamber, narrow anterior chamber angle, vitreous larger than the normal, position of vitreous protrudes anteriorly, farsightedness.

Open-angle glaucoma commonly occurs in black and white individuals because of the structural features of the eyeball and the size of the corneal curvature in black and white people. Angle-closure glaucoma often occurs in people with yellow skin. This is explained by the fact that the eyeballs of yellow people are usually small.

The disease often occurs in emotional people, the rate is higher in women than in men.

Pathogenesis

Pathogenesis of primary angle-closure Glaucoma

Pupil blocking mechanism

In eyes where the structure of the lens is larger than normal, or the position of the lens is more protruding than normal people, then the front of the lens will be close to the back of the iris, causing the pupil to block. The aqueous humor does not escape into the anterior chamber, it will be stasis in the posterior chamber, and the posterior chamber pressure increases, the iris root is pushed forward against the corneal raft, causing angle closure. The aqueous humor collects in the eyeball causing increased intraocular pressure.

Anterior occlusion of the trabecular sclera (an angle-closure mechanism)

On eyes with a small corneal structure, the anterior chamber is shallow, and the anterior chamber angle is narrow. When the pupil is dilated, the iris thickens and adheres to the back of the cornea, so the anterior chamber angle is closed. The aqueous humor does not escape through the trabecular region into the venous system, so it accumulates in the eyeball, causing glaucoma.

Angle-closure glaucoma can occur without pupillary obstruction. In some cases the iris surface is flat, the central anterior chamber appears deep. This phenomenon is due to a malformation of the iris, without pupillary obstruction. After the pupil dilates, the circumferential region of the iris convex and occludes into the trabecular region, causing angle closure.

Pathogenesis in primary open-angle glaucoma

The pathogenesis of primary open-angle glaucoma is unknown. The disease usually corresponds to optic nerve damage caused by disturbances in blood supply to the optic disc and glaucoma due to disturbances in fluid circulation.

Clinical symptoms

Primary angle-closure glaucoma

There are three clinical types: acute, subacute, and chronic.

Acute episode

This is the most typical clinical form.

Circumstances of occurrence: Sudden onset, may occur after a number of triggers such as strong emotions, systemic drug use, in the eye with parasympathetic or alpha sympathomimetic effects....

Symptoms: Suddenly, the patient feels pain in the eye, pain around the eye socket, pain spreading to the half of the head on the same side. Accompanied by the patient's vision is much blurred, the light has a red-blue halo. Sometimes the patient feels photophobia, tears but no discharge.

Physical symptoms: eyelid swelling, red eyes in the pattern of conjunctival convexity, corneal edema opaque with epithelial puffiness, shallow anterior chamber, dilated pupils deformed and unresponsive to light, edematous vitreous Blue turbidity may have anterior capsular fissures, vitreous edema. Fundus in acute attack is difficult to see due to edema of the transparent media, in cases where ophthalmoscopy can see pink optic discs, there may be peri-spinous hemorrhage.

 

Image: Acute glaucoma

Systemic symptoms: Some cases of glaucoma are accompanied by some systemic symptoms such as nausea, vomiting, abdominal pain, sweating...

Functional tests:

Visual acuity is severely reduced, sometimes only distinguishing light.

Intraocular pressure elevated above 30 mmHg can be over 60 mmHg, if you touch the eyeball, you can feel the eyeball as hard as a marble.

The vision may or may not be damaged depending on the time the patient arrives at the hospital.

Subacute bout

Circumstances of occurrence: the disease appears in waves.

Functional symptoms: The patient has intermittent pain in the eyes, a feeling of tension in the eyebrows, or a dull pain in the eye socket. Accompanied by blurred vision like through a fog, looking at lights with blue-red halos lasts a few hours, then the eyes return to normal or almost before. The pain gradually increased in frequency and intensity, vision gradually decreased.

Physical symptoms. Similar to an acute attack, but with a milder degree:

Eyes are not red or less red, intraocular pressure is increased moderately during the attack.

The vision suffers from Glaucoma damage.

The bottom of the eye has a concave optic disc.

Chronic form (atypical form)

Circumstances of appearance: The disease manifests silently.

Functional symptoms: Non-specific, patients have no eye pain, only signs of blurred vision. Sometimes the patient finds out by accidently covering one eye and seeing nothing in the other eye.

Physical symptoms: The eyelids and conjunctiva are normal. Clear cornea, shallow anterior chamber, pupils of normal size and shape; pupillary reflex may be lost (if the eye loses function):

The bottom of the eye has a concave optic papillae.

Intraocular pressure of 25 mmHg or more.

The vision is narrow.

Examine the anterior angle of the room with all angles closed 360°.

Open-angle glaucoma G

Functional symptoms: The patient sometimes has pain in the eyes, pain on the eyebrows, a blurred vision like through fog when looking at lights with the blue-red halo.

Physical symptoms:

Conjunctiva is non-conjunctival or marginally edematous

The cornea is normal in thickness and curvature.

The round pupils may be normal or slightly dilated, reflecting with or without light.

Intraocular pressure of 25 mmHg or more.

The fundus often has a concave optic disc atrophy.

The vision is often narrow.

Diagnose

Implementing the quadrants

Based on the main symptoms of the disease:

Intraocular pressure above 25 mmHg.

The vision may or may not be hurt.

The fundus may have a concave optic disc.

Morphological diagnosis

Closed angle glaucoma

Shallow anterior chamber, closed anterior chamber angle

Opened angle glaucoma

Deep anterior chamber, opened anterior chamber angle

Differential diagnosis

Acute conjunctivitis

Acute conjunctivitis

  Glaucoma
     

- No pain, just itching like sand in your eyes

- Much dirty eye fluid

- Concentration shallow conjunctiva

- Components of the normal eyeball

- Normal eyesight

- Normal palpable intraocular pressure

 

- Eye pain, migraine on the same side

- Glare, watery eyes, no dirty eye fluid

- Red conjunctiva in a fringe-concentrated pattern

- Corneal edema, shallow anterior chamber angle, narrow anterior

chamber angle, concave atrophy of the optic nerve

- Visual acuity is severely reduced

- High palpable intraocular pressure

Iritis 

Functional symptoms are the same as in glaucoma: All patients have pain in their eyes and blurred vision

Physical symptoms have different signs as follows:

Iritis 

 

Glaucoma

     

- The cornea is not edematous, but there are some small precipitates on the back

- Deep anterior chamber, Tyndall(+), or with pus

- Pupils are small, sticky, distorted, no response to light

- Intraocular pressure is usually not high

 

- Corneal edema, epithelial puffiness

- Clean, shallow anterior chamber, narrow anterior chamber angle

- Distorted pupils, loss of response to light

- High intraocular pressure 25 mmHg

Treatment of angle-closure Glaucoma

Principles

Surgical treatment is indicated for all stages of the disease. Medical treatment is only indicated temporarily in emergency cases as well as during the waiting period for surgery, or in cases where the patient has a severe systemic disease that is not able to be surgically treated.

Treatment methods

Medical:

Topical medication with miosis drugs such as Pilocacpin 1% x 3 to 6 times a day.

Whole body: Take acetazolamide 0.25g x 2-4 tablets in 1 day divided into 2 times

For cases of fulminant attacks, patients with vomiting a lot, oral drugs are not effective, patients can be prescribed Diamox 500 mg x 1 slow intravenous injection.

In addition, pain relievers and sedatives can be used.

Surgery:

Prophylactic peripheral iridotomy: Laser or surgical. This method is indicated for eyes diagnosed with latent or primary angle-closure glaucoma where the angle remains open above half of the circumference.

Tracheotomy: Indicated for cases when the anterior chamber angle has more than 180° of the closure angle.

Treatment of Open Angle Glaucoma

The principles of treatment

Treatment is aimed at lowering intraocular pressure, without further damaging the visual field and disc state. Treat with eye drops or laser first. Surgery is indicated when medical or laser treatment is not effective or in cases where there are no economic and health conditions, periodical follow-up.

Treatment methods

Medical

Topical drugs: Drugs to treat open-angle glaucoma are divided into several groups.

Parasympathomimetic drugs: Pilocacpin 1% x 3 times in 1 day.

Sympathomimetic agents: Ephedrine.

Sympathomimetic beta-blockers such as Betoptic 0.25%-0.5%, Timolol 0.5%, Timoptic 0.5%, Nyolol 0.5%... these drugs have the effect of reducing excretion hydrolysis.

Prostaglandin derivatives: Travatan, Xalanta. The effect of enhancing the circulation of aqueous humor through the scleral uveal pathway

Systemic drugs: Preoperative treatment only, not prolonged use. The dosage is the same as in angle-closure glaucoma.

Laser treatment

Shaping raft area by ND-YAG laser, ruby ‚Äč‚Äčlaser, diode laser. The laser beam is used to create burns at the ciliary dissolution and iris root to create traction scars to widen the trabecular foramen.

Surgery

Deep sclerectomy: Indicated in the early stages of the disease

Trabeculectomy: Indicated for late stages or cases of failed deep sclerectomy.

Early detection of Glaucoma

Primary Glaucoma is familial and spontaneous without external factors, so primary Glaucoma prevention is very difficult to implement. However, in order to reduce the rate of blindness due to glaucoma, it is necessary to detect it early.

Objects needed for early detection of Glaucoma

These subjects are people at high risk of disease.

The blood relatives of most primary glaucoma patients are those over 35 years of age.

People with eyes with an anatomical structure favorable to glaucoma.

People with symptoms suspected of glaucoma:

Eye pain, blurred vision, a red halo of lights

The intraocular pressure is between 22 mmHg and 24 mmHg.

Fundus with concave spines wider than 3/10, especially in cases of concave optic discs in two asymmetrical eyes.

Methods for early detection of Glaucoma

IOP monitoring: This method should only be performed in ophthalmology facilities, or by qualified technicians or nurses who accurately measure intraocular pressure.

Measure intraocular pressure for these groups of subjects from 2 to 6 times in 1 day, continuously monitor for 3 consecutive days.

Early detection by test types: This method is performed at ophthalmology facilities, the appointment of the test type is given by the doctor after carefully examining the patient and divided into 2 diagnostic groups:

Cases leading to the diagnosis of angle-closure glaucoma (individuals of patients with angle-closure glaucoma; people with small eyes, high farsightedness, shallow anterior chamber angle narrow anterior chamber): Using the prone, dilated test pupil, read a book or try drinking water combined with pupil dilation.

Those aiming for the diagnosis of open-angle glaucoma (blood relatives of glaucoma patients with the open-angle disease, those with symptoms of glaucoma on clinical examination with deep anterior chambers): Use the water-dose test or the oral test. water combined with pupil dilation.

How to evaluate results?

Positive result:

Diagnosed with Glaucoma.

The intraocular pressure after monitoring or after testing is 25 mmHg or higher.

The difference in intraocular pressure in 24 hours in the same eye is 5 mmHg or more.

After testing the intraocular pressure increased more than 5 mmHg in the same eye

Negative results:

Glaucoma is not thought of, but the patient needs to be monitored.

Some methods contribute to the early detection of glaucoma

Propaganda for the people to have a certain understanding of the symptoms of glaucoma so that patients can self-diagnose their disease and go to the ophthalmology clinic early.

Glaucoma, even though it has been treated by any method, has a certain recurrence rate, so patients need to be periodically monitored at ophthalmology facilities.

Prevention

Primary glaucoma cannot be prevented. However, a number of other causes can lead to secondary glaucoma. The progression of secondary glaucoma is also very severe and can lead to blindness like primary glaucoma. Therefore, the prevention of secondary glaucoma also contributes to reducing the rate of blindness due to glaucoma.

Some causes of secondary glaucoma

Long-term treatment of ocular and systemic corticosteroid preparations.

Patients with diabetes are not closely monitored and controlled blood sugar.

Patients with high blood pressure have eye complications but are not treated properly and promptly.

The patient suffered from uveitis, suffered an injury, burned his eye, and was not treated in time.

The patient has a late-stage cataract that causes glaucoma complications.

Issues to propagate in the community

People should not abuse drugs containing corticosteroids, especially those in the eyes because it can lead to blindness due to glaucoma, cataracts, corneal ulcers. If systemic corticosteroid therapy is required in some other diseases, it is necessary to closely monitor intraocular pressure to promptly detect drug-induced complications.

People with diabetes, high blood pressure need to be properly treated to keep blood sugar, or blood pressure stable in the normal range, on the other hand, must have periodic fundus examination to detect retinal deficiency blood caused by these diseases for laser treatment of neovascular glaucoma.

People who are diagnosed with cataracts need to be monitored and operated on at the right time to avoid complications caused by late-stage cataracts.

Teach people how to give first aid to chemical burns and injuries. Correctly and aggressively treat burns or injuries to avoid complications of iris adhesion

It is necessary to detect eye diseases and transfer them to a higher level in time.