Glaucoma

Have you ever heard that glaucoma is the “vision thief”? Because some glaucoma causes vision loss, you will not be aware of its existence, there will be no pain or symptoms, and there will be no recovery after suffering from it. The causes of glaucoma include: profound myopia/hyperopia, sleep apnea, long-term migraines, etc. If you have these causes, you need to have regular eye examinations. Once glaucoma is discovered, you need to seek treatment advice from an ophthalmologist immediately. Early detection and treatment of eye diseases can reduce the chance of visual impairment.

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What is Glaucoma?

Glaucoma is usually caused by excessive internal eye pressure, resulting in progressive degeneration to the retina and fibres on the optic nerve in the posterior chamber of the eye. Yet, there are cases where the normal pressure (within 10-21 mmHg) the optic nerve is still unable to withstand and is thus damaged, resulting in visual loss. Patients with glaucoma may experience peripheral vision loss followed by a decrease in central vision. Vision loss or even complete blindness may occur without proper treatment. Glaucoma has no obvious signs and symptoms and is usually difficult to detect. Many patients may be ignorant about their condition until the field of vision has sustained irreversible narrowing damage. Women are at higher risk of developing acute glaucoma, especially in middle age and beyond. However, even children can develop such illness.

Types of Glaucoma

Chronic Glaucoma

There is no apparent symptom in the early stage. In the later stages of the disease, the vision field is narrowed and only the central vision is left, so that patients cannot see images beyond the central field of vision, forming a “tunnel vision”. If the condition continues to deteriorate, it could lead to total blindness.

Acute Glaucoma

A sudden increase in intraocular pressure may cause acute glaucoma, with the following symptoms suddenly appearing: blurred vision, rainbow circles when looking at lights, red eyes, corneal opacity, severe eye pain with accompanying headache, nausea and vomiting. Acute glaucoma may cause permanent loss of vision within a day, so it is necessary to seek medical advice early and have regular eye examinations.

Primary and Secondary Glaucoma
Glaucoma

There is no apparent cause of primary glaucoma, and patients with this condition are affected by other factors. As for secondary glaucoma, it is caused by other diseases that result in elevation of the eye pressure, including hypermature cataract, iritis, intraocular haemorrhage, tumours, trauma, postoperative complications and inappropriate use of steroids and so forth.

Causes of Glaucoma

Aged 40 or above

Aging plays an important role in glaucoma, as its prevalence increases exponentially with age. However, the pathophysiology of increasing age as a risk factor for glaucoma is unclear.

Family inheritance

While everyone can develop glaucoma, you may be at higher risk if glaucoma runs in your family. The most common form of glaucoma, open-angle glaucoma, is hereditary. If you have an immediate family member with glaucoma, your risk of developing the disease is 4 to 9 times higher.

History of eye injury
(especially blunt trauma)

If the eyeball is unfortunately hit head-on by a fast-moving hard object, it may cause bleeding of the iris and other structures, block the flow of aqueous humor, and cause an increase in intraocular pressure. With proper treatment, the optic nerve can be protected from permanent damage. However, if the structure near the ciliary body or trabeculae is damaged due to impact, it may affect the drainage system, causing long-term increase in intraocular pressure and inducing glaucoma.

High myopia/hyperopia

In addition to people with hyperopia who are prone to corner-angle closed glaucoma, high myopia is also one of the causes of chronic open-angle glaucoma. Studies have also pointed out that myopic eyes are more susceptible to increased intraocular pressure; if myopia of more than 400 degrees is accompanied by increased intraocular pressure, it is more likely to cause visual field defects.

Diabetes

The relationship between diabetes and open-angle glaucoma, the most common type of glaucoma, has intrigued researchers for years. People with diabetes are twice as likely to develop glaucoma as people without diabetes.

Sleep Apnoea

In recent years, literature research has pointed out that sleep apnea is related to glaucoma. It is possible that the patient's body is deprived of oxygen during sleep, which affects the blood circulation around the eyeballs, deprives the optic nerve of oxygen, and slowly degrades vision.

Chronic migraine

Glaucoma is generally divided into acute and chronic. Among them, acute glaucoma is mostly the cause of obvious migraine. Because the outlet opening of the anterior chamber of the eyeball is occluded in a short period of time, the intraocular pressure rises rapidly, and corneal edema is more common, causing severe headaches. Therefore, it is easily mistaken for migraine and treatment is delayed.

Cardiovascular disease

High blood lipids may also cause glaucoma. Although it does not directly cause eye disease, research statistics show that it does cause an increase in intraocular pressure, thereby increasing the risk of glaucoma.

Hypertension

Studies have found that patients with high blood pressure are twice as likely to suffer from "normal intraocular pressure glaucoma" as other people. This is because high blood pressure can damage the blood circulation regulation system of the eyeball and cause blood flow in the eyeball to be disordered. Therefore, although the intraocular pressure is normal, it will accelerate the withering of the optic nerve.

Increased eye pressure
due to steroid use

Steroid glaucoma is one of the sequelae of long-term use of steroids and is also considered a type of open corner glaucoma. Long-term use of steroids may cause the aqueous humor drainage hole of the eyeball to be blocked, resulting in a decrease in the drainage rate of aqueous humor and an increase in intraocular pressure. However, as long as the use of steroids is stopped, the intraocular pressure of most patients can drop to the normal range.

Symptoms of Glaucoma

Chronic Glaucoma

No obvious sign and symptom in the early stage. Over time, the peripheral vision shrinks and the patient loses central vision.

Acute Glaucoma

Eye redness, seeing rainbow circles around lights, vision loss, eye pain, headache and vomiting, etc.

Glaucoma treatment methods

According to statistics, there are approximately 120,000 glaucoma patients in Hong Kong, of whom 5% are over 40 years old. Currently, glaucoma cannot be cured or the lost vision can be restored. However, as long as glaucoma examination (checking intraocular pressure, cornea and other health conditions) and diagnosis are carried out early, and appropriate treatment is given, vision loss can still be prevented or slowed down.

Treatment plans	Principles of treatment methods	Degree of illness
Eye Drops	In the early stage of the disease, drugs (eye drops) can be used to control the disease, which can protect and maintain the patient's optic nerve tissue and its functions, control the intraocular pressure level to an appropriate target range, reduce further damage to the optic nerve, and stabilize the visual function. main purpose. Compared with other treatment options, eye drops cause fewer serious side effects and are safer than surgery and laser treatment.	Initial treatment
Laser trabeculoplasty	By creating small holes around the iris, the flow of aqueous humor is promoted to reduce intraocular pressure.	Open-angle glaucoma (initial treatment)
Peripheral iridectomy	Laser is used to stimulate the drainage structure in the eye, increase fluid drainage, and help reduce intraocular pressure.	Open-angle glaucoma (mid-term treatment)
Selective laser trabeculoplasty	Lasers are used to repair specific mesh structures to promote drainage and reduce intraocular pressure.	Open-angle glaucoma (mid-term treatment)
Micropulse light cyclophotocoagulation	Micropulse light is used to irradiate the ciliary body tissue to reduce the production of aqueous humor to reduce intraocular pressure.	Patients with refractory glaucoma or those who require further intraocular pressure control

Caution

Prolonged use of eye drops may cause dryness and redness in the eyes and may even cause allergy and discomfort.

Glaucoma FAQ

Does it have to be high eye pressure to have glaucoma?

No, there is a type of glaucoma called low-tension glaucoma, where the eye pressure is below 21mmHg (glaucoma is generally suspected when the eye pressure is above 21mmHg).

Could headache be caused by glaucoma?

There can be many reasons for headaches, but it turns out that many of them have nothing to do with the "head" but are related to the eyes, which are called "ocular headaches." One of the common conditions is acute glaucoma. Because the outlet opening of the anterior chamber of the eyeball is occluded in a short period of time, intraocular pressure rises rapidly, and corneal edema is more common, eventually leading to severe headaches, which can easily be mistaken for migraine. If treatment is delayed, it may damage the optic nerve and even cause the patient to lose vision rapidly. Therefore, if you continue to have headaches, eye pain, worsening headaches when pressing the eyeballs, blurred vision, and nausea, you should seek help from an ophthalmologist as soon as possible.

How to detect early-stage glaucoma?

Because early-stage glaucoma has no obvious symptoms, it steals vision silently at any time. When you find that your field of vision is narrowed, irreversible damage has been done to your eyes. Therefore, it is recommended that adults undergo regular comprehensive eye examinations every one to two years to check intraocular pressure, cornea and other eye health conditions to avoid missing opportunities to control the disease.