Glaucoma
Glaucoma is a group of eye conditions that damage the optic nerve, often due to abnormally high pressure inside the eye. Left untreated, glaucoma can lead to irreversible vision loss or even total blindness. It is one of the leading causes of preventable blindness worldwide, particularly among people over the age of 60. However, early diagnosis and proper treatment can preserve sight and significantly slow progression.
The disease is typically painless in its early stages, which makes it particularly dangerous. Many people do not realise they have glaucoma until permanent damage has already occurred. Because of this, regular eye tests—especially after the age of 40—are vital to detect the condition before symptoms become apparent.
What Is Glaucoma?
Glaucoma refers to a family of eye diseases that share a common characteristic: progressive damage to the optic nerve, which connects the eye to the brain and is responsible for transmitting visual signals. Damage to the nerve impairs peripheral vision initially and can eventually affect central vision.
In many cases, the damage is associated with elevated intraocular pressure (IOP), which results from a build-up of aqueous humour—the fluid inside the front part of the eye. When this fluid does not drain properly, pressure increases and damages the nerve fibres in the optic nerve.
However, not all glaucoma patients have high eye pressure. In normal-tension glaucoma, optic nerve damage occurs despite IOP being within the normal range, likely due to poor blood flow or other risk factors.
Types of Glaucoma
There are several different forms of this condition, each with its own causes and characteristics:
1. Primary Open-Angle Glaucoma
The most common type worldwide
Caused by slow clogging of the eye’s drainage canals
Develops gradually and often without symptoms
Peripheral vision is affected first
2. Angle-Closure Glaucoma (Acute Glaucoma)
Less common but more dangerous
Occurs when the iris bulges forward and blocks the drainage angle
Sudden increase in IOP leads to eye pain, redness, headache, and blurred vision
A medical emergency that requires immediate treatment
3. Normal-Tension Glaucoma
Optic nerve damage occurs despite normal IOP levels
Risk factors include poor circulation, migraines, and vascular conditions
4. Congenital Glaucoma
Present at birth due to developmental defects in the eye
Symptoms include clouded cornea, enlarged eyes, and excessive tearing
Requires surgery and lifelong monitoring
5. Secondary Glaucoma
Caused by an underlying condition such as eye injury, inflammation, steroids, or diabetes
Can mimic open-angle or angle-closure types
Risk Factors
Certain factors increase the risk of developing this condition:
Age over 60
Family history of this condition
African, Asian, or Hispanic ancestry
High eye pressure (IOP)
Thin corneas
Diabetes or hypertension
Prolonged use of corticosteroids
Eye injuries or surgery history
Because many of these risk factors are silent, routine eye screening is the most effective way to catch glaucoma early.
Symptoms
In its early stages, this conditionoften has no noticeable symptoms. This is why it is often called the “silent thief of sight.”
In Primary Open-Angle Glaucoma:
Vision loss begins at the edges of visual field
May go unnoticed until significant peripheral vision is lost
Gradually progresses to central vision if untreated
In Acute Angle-Closure Glaucoma:
Sudden onset of severe eye pain
Redness, haloes around lights, and blurred vision
Nausea and vomiting
Requires immediate medical intervention to prevent permanent blindness
How Glaucoma Is Diagnosed
Routine eye exams include several tests to detect this condition, such as:
Tonometry: Measures eye pressure
Ophthalmoscopy: Examines the optic nerve
Visual field testing: Detects peripheral vision loss
Pachymetry: Measures corneal thickness
Gonioscopy: Checks the drainage angle
Most people are diagnosed during routine check-ups, underscoring the importance of regular eye care, especially in those with risk factors.
Prevention and Screening
While glaucoma cannot always be prevented, its progression can be significantly delayed. Prevention strategies include:
Regular eye exams: Every 2 years for those over 40; annually if at risk
Managing diabetes and blood pressure
Protecting eyes from injury
Avoiding prolonged steroid use unless medically necessary
Early detection remains the most powerful tool in preserving vision.
The Impact of Untreated Glaucoma
If glaucoma is not diagnosed or managed, it can lead to:
Permanent vision loss
Blindness
Reduced independence and quality of life
Vision lost to glaucoma cannot be restored, which is why timely diagnosis and ongoing treatment are essential.
Living with Glaucoma
With proper care, most people with this condition retain good vision throughout life. Key to this is:
Adherence to medication
Routine follow-up with an ophthalmologist
Reporting any new vision changes promptly
Understanding glaucoma empowers individuals to seek appropriate care, protect their sight, and lead full, independent lives.
