Glaucoma: Types, Development, Causes, Symptoms, Diagnosis And Treatment

Glaucoma: Types, Development, Causes, Symptoms, Diagnosis And Treatments.

What is Glaucoma?

Glaucoma can be defined as a group of eye conditions that damage the optic nerve. Optic nerve is responsible for carrying impulses from retina to the brain for sight. When glaucoma damage the optic nerve, it causes irreversible blindness.

Glaucoma is the leading cause of irreversible blindness globally affecting people at any age but more common in older adults. It is referred as a silent vision stealer, even with treatment about 15% of individuals with glaucoma become blind in at least one eye within 20 years.

How glaucoma developed?

Glaucoma develops as a result of elevated intraocular pressure (IOP) due to build up of aqueous humor. The fluid (aqueous humor) is usually produced by the ciliary body cells, passing from posterior chamber to anterior chamber through the trabecular meshwork (the angle between the Iris and Cornea), and finally draining in to schlemm's canal and the aqueous and episcleral veins. When the fluid is over- produced or the drainage system does not work properly, it can not flow out of its normal rate and pressure builds up beyond intraocular pressure of 15mmHg using applanation tonometer or schiotz tonometer.

  Types of Glaucoma

There are three types of glaucoma as listed and explained below:

Chronic/pen angle glaucoma

Acute/closed or narrow glaucoma

Congenital glaucoma

1. Chronic/open angle glaucoma

This is the most common type of glaucoma in West Africa sub-region.

It occurs in people 35 years and above with usually a family history, giving few warning signs until permanent damage already occurred.

Groups at risk of chronic/open angle glaucoma:

Diabetic patient

Very short sighted people

Older age group

Relatives of the patient (as hereditary disease condition).

What are the signs and symptoms of chronic/open angle glaucoma?

These includes:

One pupil may be dilated than the other and reacts slowly to light.

Gradual visual deterioration with a low grade pain behind or in the eye.

Visual field loss only picked up in severe cases.

Disc changes or change of glasses oftenly.

There may be no severe symptoms, no irritation or redness.

2. Acute/closed angle glaucoma

Acute/closed angle glaucoma is less common variety in the negroid (black people of African race) and occurs suddenly, therefore regarded as a medical emergency.

Groups at risk of acute/closed angle glaucoma include long sighted people and people over 65 years of age.

What are signs and symptoms of acute/closed angle glaucoma?

These signs and symptoms include:

Swollen eye lids with very red eye and cloudy cornea.

Sudden painful red eye with reduction in vision.

Severe headache

Nausea and vomiting

Dilated pupil and not responding to to light.

Patient may see coloured rings around light prior to onset of acute attack.

3. Congenital glaucoma

This is more common in population practising consanguineous marriage. Moreover, it is a rare condition presented at birth or within the first 2 years after birth, second to mother to child transmission of rubella during first trimester of pregnancy.

Signs And Symptoms Of Congenital Glaucoma.

Excessive watering of the eye

Large eye ball with an oxy cornea termed as 'Buphthalmos'.

Failure of the child to open eye in the sun or where there is light.

It may affect one or both eye.

Hazy and large cornea.

What causes Glaucoma?

Experts are unsure of the precise causes of glaucoma, but cases are divided into two categories:

Primary glaucoma: This means that the cause is unknown.

Secondary glaucoma: The condition has a known cause, such as a tumor, diabetes, an advanced cataract, or inflammation.

  Risk factors of glaucoma

Because chronic forms of glaucoma can destroy vision before any signs or symptoms are apparent, be aware of these risk factors:

Old age.

Ethnic background: East Asians, African Americans, and those of Hispanic descent have a higher risk of developing glaucoma, compared with Caucasians.

Some illnesses and conditions like diabetes or hypothyroidism.

Eye injuries or conditions.

Eye surgery.

Myopia (short sightedness).

  Corticosteroids

Patients on long-term corticosteroids have a raised risk of developing several different conditions, including glaucoma. The risk is even greater with eye drops containing corticosteroids.

How glaucoma is diagnosed?

Your doctor will review your medical history and conduct a comprehensive eye examination. He or she may perform several tests, including:

Measuring intraocular pressure (tonometry)

Testing for optic nerve damage with a dilated eye examination and imaging tests

Checking for areas of vision loss (visual field test)

Measuring corneal thickness (pachymetry)

Inspecting the drainage angle (gonioscopy)

  Complications of glaucoma

If glaucoma left untreated, it could lead to loss of vision in one or both eye or even blindness.

How Is Glaucoma Treated?

The goal of glaucoma treatment is to reduce IOP to stop any additional eyesight loss. Typically, your doctor will begin treatment with prescription eye drops. If these don’t work or more advanced treatment is needed, your doctor may suggest one of the following treatments:

Medications

Several medicines designed to reduce IOP are available. These medicines are available in the form of eye drops or pills, but the drops are more common. Your doctor may prescribe one or a combination of these.

Surgery

If a blocked or slow channel is causing increased IOP, your doctor may suggest surgery to make a drainage path for fluid or destroy tissues that are responsible for the increased fluid.

Treatment for angle-closure glaucoma is different. 

This type of glaucoma is a medical emergency and requires immediate treatment to reduce eye pressure as quickly as possible. Medicines are usually attempted first, to reverse the angle closure, but this may be unsuccessful. A laser procedure called laser peripheral iridotomy may also be performed. This procedure creates small holes in your iris to allow for increased fluid movement.

Will a Person with Glaucoma Go Blind?

If your increased IOP can be stopped and the pressure returned to normal, vision loss can be slowed or even stopped. However, because there’s no cure for glaucoma, you will likely need treatment for the rest of your life to regulate your IOP. Unfortunately, vision lost as a result of glaucoma cannot be restored.

How to prevent glaucoma?

Glaucoma can not be prevented but early diagnosis and prompt attention would prevent blindness.

These self-care steps can help you detect glaucoma in its early stages, which is important in preventing vision loss or slowing its progress:

Regular eye check up, every four years beginning at age of 40s in the absence of risk factors, or every two years if at risk or over sixty five years.

Ask your doctor to recommend the right screening schedule for you.

Know your family's eye health history. 

Glaucoma tends to run in families. 

If you're at increased risk, you may need more frequent screening.

  Exercise safely

Regular, moderate exercise may help prevent glaucoma by reducing eye pressure. Talk with your doctor about an appropriate exercise program.

 Regular Taking of prescribed eyedrops  

Glaucoma eyedrops can significantly reduce the risk that high eye pressure will progress to glaucoma. To be effective, eyedrops prescribed by your doctor need to be used regularly even if you have no symptoms.

  Wear eye protection 

Serious eye injuries can lead to glaucoma. Wear eye protection when using power tools or playing high-speed racket sports in enclosed courts.

Sources:

Community Health Unpublished Lecture Note.

www.medicalnewstoday.com

www.mayoclinic.org

www.healthline.com