Glaucoma Vision’s Silent Killer

Dr. Dexter LEUNG

Honorary Consultant in Ophthalmology

Specialist in Ophthalmology

It is estimated that at least 2 in every 100 adults aged above 40 have glaucoma. In the absence of early symptoms, glaucoma is often neglected and has already reached an advanced stage when diagnosed.

Causes of Glaucoma

The eyeball contains a transparent fluid called "aqueous humour", which flows continuously like a tap left running. If it flows too fast or clogging occurs, the intraocular pressure will increase and cause damage to the eye and optic nerves, resulting in poor vision or even blindness. Optic nerves are prone to damage in some patients despite normal intraocular pressure.

For early detection and diagnosis, doctors will measure the intraocular pressure and conduct thorough examination.

Types of Glaucoma and Symptoms

• Acute Glaucoma: blurred vision, halos, eye pain, redness, headache, nausea, vomiting, etc.
• Chronic Glaucoma: vision deterioration and gradual narrowing of the field of vision with no telltale symptoms
• Congenital Glaucoma: sensitivity to light and large watery eyes (due to defective aqueous drainage)
• Primary Glaucoma: due to conditions other than systemic diseases or eye conditions
• Secondary Glaucoma: due to other systemic or underlying eye diseases
• Normal Tension Glaucoma: it occurs when the optic nerves cannot withstand normal intraocular pressure
• Hypertensive Glaucoma: it occurs when increased intraocular pressure damages the optic nerves, causing deteriorated vision and narrowed field of vision.

Glaucoma may also reflect one’s physical well-being, as glaucoma can be associated with cardiovascular health.  Patients with cardiovascular conditions and high blood pressure should be aware of any sign of glaucoma. A comprehensive check-up is recommended.

Treatment of Glaucoma

Glaucoma is treated by restoring the intraocular pressure to normal or lower level to alleviate or prevent further damage to the optic nerves. Depending on glaucoma type, eye drops, oral medications, laser treatment or surgery may be prescribed for treatment. For some patients, prophylactic laser peripheral iridotomy or drug treatment may be considered for the healthy eye to prevent acute glaucoma.

Risk Factors of Glaucoma

• Family history of glaucoma
• High myopia/high hyperopia
• Diabetes mellitus
• Cardiovascular and cerebrovascular diseases
• Sleep apnea
• Migraine
• Underlying eye conditions, e.g. uveitis, a history of eye injury

Glaucoma may cause permanent blindness if untreated, and the key to prevention is early diagnosis and treatment. Adults aged over 40 years, especially those with the above risk factors, should undergo eye examination every 1 or 2 years. Regular eye check-up is particularly important to patients with cardiovascular and cerebrovascular diseases.