Taking A Closer Look At Glaucoma

Glaucoma is a group of conditions that causes damage to the optic nerve. It is one of the leading causes of blindness in people above the age of 60 years. Although acute angle-closure glaucoma is a medical emergency, there are other types of glaucoma that have no early symptoms and your vision may seem normal until the problem is advanced. This article explains what glaucoma is, its symptoms, diagnosis, and treatment.

What is glaucoma?

Glaucoma is a group of diseases that damages the optic nerve and is commonly associated with an increase in the pressure in the eyes (intraocular pressure or IOP). Untreated or improperly managed glaucoma can cause blindness and irreversible vision loss.

What are the types of glaucoma?

The four main forms of glaucoma are –

Open-angle glaucoma
Angle-closure glaucoma (also called closed-angle glaucoma)
Congenital glaucoma
Secondary glaucoma

Open-angle glaucoma is the most prevalent kind of glaucoma. There is no known cause. Over time, the ocular pressure gradually rises. The optic nerve gets compressed against this increasing pressure and, as a result, blind spots occur in your vision. Open-angle glaucoma frequently runs in families.

Angle-closure glaucoma (Closed-angle glaucoma) develops when the intraocular fluid gets suddenly blocked and cannot flow out of the eyes. It leads to a sudden, significant increase in ocular pressure. Acute glaucoma attacks can be brought on by dilating eye drops and some medications.
Closed-angle glaucoma is an emergency condition.

Congenital glaucoma occurs when the eyes do not develop normally. Here, the angle of the anterior chamber of the eye is abnormal, leading to high intraocular pressure. This is usually detected at the time of birth.

Secondary glaucoma develops because of some underlying cause. Medications like corticosteroids, illnesses of the eyes such as uveitis (an inflammation of the middle layer of the eye), diseases like diabetes, and eye damage are some of the reasons for secondary glaucoma.

What are the causes of glaucoma?

Glaucoma can develop without any known cause, but a number of things can influence it –

High intraocular eye pressure can cause mechanical strain on your optic nerve and lead to damage of the nerves in the eye and altered blood supply. This increase in pressure can be due to factors like genetics, increasing age etc.
Insufficient blood supply to the optic nerve
Exposure to toxins such as free radicals, nitric oxide etc.

What are the risk factors for glaucoma?

Some risk factors for glaucoma include –

Positive family history
Increasing age
Short-sightedness
Diabetics
High blood pressure
Cigarette smoking
Unregulated usage of topical drugs like steroids

What are the symptoms of glaucoma?

Certain types of glaucoma are usually difficult to diagnose because there aren’t any warning signs. Symptoms of vision abnormalities may appear gradually, making them easy to overlook. Routine eye exams are crucial for identifying open-angle glaucoma because many sufferers don’t exhibit any obvious symptoms; symptoms of closed-angle glaucoma are more severe and appear unexpectedly. You may encounter any type of these symptoms like –

Eye pressure or discomfort
Headaches
Lights with rainbow-coloured halos
Vision problems such as tunnel vision, poor eyesight, blurriness, or blind spots
Difficulty in reading or looking at things up close
Nausea and vomiting
Redness of the eyes

How is glaucoma diagnosed?

For the purpose of detecting glaucoma or other eye issues, routine eye exams are crucial. An eye doctor may do one or more of these painless tests to check for glaucoma

Tonometry is an ocular test that is used to measure eye pressure. Most commonly a puff of air is blown into your eye as you look at a bright light
Dilated eye exam is done to visualise the optic nerve at the back of the eyes
Visual acuity test (eye charts) is used to check for vision loss
Visual field testing checks your field of vision. Cover one eye and look straight ahead while your doctor stands in your peripheral vision holding up his fingers and asking you how many you can see
Optical coherence tomography is used to examine for abnormalities in your optic nerve
Pachymetry is used to measure corneal thickness
Slit-lamp exam uses a specialised microscope called a slit lamp to examine the interior of your eye

How is glaucoma is treated?

Glaucoma that is left untreated can hasten the progression of permanent vision loss and blindness. If you are experiencing eye pain, headaches, or problems with your vision, it’s crucial to see an eye doctor as soon as possible. The initial treatment includes eye drops and oral medications, and then in the later phase, further procedures like laser treatment and surgeries are usually done.

Eye drops are used for decreasing intraocular pressure by either accelerating the passage of the fluid out of your eyes or reducing its production. These include beta-blockers, prostaglandin analogues, adrenergics and carbonic anhydrase inhibitors. Common side effects include allergies, redness, stinging, blurred vision, and itchy eyes. Make sure your doctor knows all of your current medications and any other medical conditions you have because there may be drug interactions.

Oral medication such as beta blockers and carbonic anhydrase inhibitors are mostly prescribed as they reduce fluid production in the eyes.

Laser surgery can cause a modest increase in the drainage of fluid from your eyes if you have open-angle glaucoma. If you suffer from angle-closure glaucoma, it can prevent fluid blockage. Procedures for laser consist of –

Trabeculoplasty which is used to open up the drainage area
Iridotomy which makes a tiny hole in your iris for the fluid to flow more easily
Cyclophotocoagulation which reduces fluid production by treating the ciliary process

Surgery is another way to reduce eye pressure, it also provides better eye pressure control than eye drops and oral medications in severe cases. This includes –

Microsurgery: It is a procedure in which your doctor constructs a new channel to drain the fluid and lower eye pressure during a treatment known as a trabeculectomy. This surgery has to be done more than once

Minimally invasive glaucoma surgeries (MIGS) are less invasive surgeries that use microscopic apparatus to make tiny openings and allow fluid to drain

How can I prevent glaucoma?

You can’t prevent glaucoma, but if you identify it early, you can lower your risk of permanent vision loss. Some preventative measures include –

Regular eye checkups which should be done every one to two years if you are over 40 years and have a family history of the condition. You might need checkups more frequently if you have health issues like diabetes or are at risk for other eye illnesses
Protecting your eyes by wearing protective eyewear
Follow your doctor’s instructions if you have been diagnosed with increased intraocular pressure

What are the complications of glaucoma?

Untreated glaucoma can lead to permanent visual impairment and even blindness.

Can glaucoma be cured?

Unfortunately, there is no cure for glaucoma at present. You can, however, if identified and managed well, you will be able to control the symptoms and delay the progression of the disease.