Glaucoma is a group of eye diseases that damage the optic nerve, which is essential for clear vision. It is one of the leading causes of irreversible blindness worldwide, yet many people are unaware they have the condition until significant vision loss has occurred. Glaucoma often develops slowly and painlessly, making early detection through regular eye examinations crucial. The World Health Organization identifies glaucoma as a major cause of global vision impairment. With timely diagnosis and appropriate treatment, further vision loss can often be prevented.
What Is Glaucoma
Glaucoma occurs when damage to the optic nerve gradually impairs the transmission of visual information from the eye to the brain. This damage is most commonly associated with increased pressure inside the eye, known as intraocular pressure. However, glaucoma can also occur when eye pressure is within the normal range. The condition affects peripheral vision first and may eventually lead to total blindness if left untreated.
Types of Glaucoma
The most common form is primary open-angle glaucoma, which develops gradually as the eye’s drainage system becomes less efficient, causing pressure to build up over time. Angle-closure glaucoma is less common but more serious and occurs when the drainage angle of the eye becomes blocked suddenly, leading to a rapid rise in eye pressure. Other types include normal-tension glaucoma, where optic nerve damage occurs despite normal eye pressure, secondary glaucoma caused by injury, inflammation, or medication, and congenital glaucoma, which is present at birth due to abnormal eye development.
Causes of Glaucoma
Glaucoma is usually caused by an imbalance between the production and drainage of fluid inside the eye. This fluid, called aqueous humour, normally drains through a mesh-like channel. When drainage is reduced or blocked, fluid accumulates and increases pressure within the eye, damaging the optic nerve. The exact reason why some optic nerves are more vulnerable to damage is not fully understood, but blood flow to the optic nerve may also play a role.
Symptoms of Glaucoma
In the early stages, glaucoma often causes no noticeable symptoms, particularly in open-angle glaucoma. Vision loss begins at the edges of the visual field and progresses slowly, which is why it may go unnoticed for years. As the disease advances, tunnel vision may develop. Angle-closure glaucoma can cause sudden symptoms such as severe eye pain, headache, blurred vision, halos around lights, nausea, and vomiting. This form is a medical emergency and requires immediate treatment.
Risk Factors for Glaucoma
Several factors increase the risk of developing glaucoma. These include increasing age, a family history of glaucoma, African, Caribbean, or Asian ancestry, high intraocular pressure, thin corneas, and certain medical conditions such as diabetes and high blood pressure. Long-term use of corticosteroid medicines, especially eye drops, also increases risk. Eye injuries and severe short-sightedness or long-sightedness are additional contributing factors.
Diagnosis and Eye Screening for Glaucoma
Glaucoma is diagnosed through a comprehensive eye examination. This includes measuring intraocular pressure, examining the optic nerve, testing peripheral vision, and assessing the thickness of the cornea. Imaging tests may be used to monitor changes in the optic nerve over time. Because glaucoma can develop without symptoms, regular eye checks are essential, particularly for people at higher risk.
Treatment Options for Glaucoma
Although glaucoma cannot be cured, treatment can slow or stop further vision loss. The main aim of treatment is to lower eye pressure. This is commonly achieved with prescription eye drops that reduce fluid production or improve drainage. Oral medicines may be used in some cases. Laser treatment can help improve fluid outflow, and surgical procedures may be recommended when other treatments are not effective. Lifelong monitoring and adherence to treatment are critical for protecting vision.
Living With Glaucoma
Living with glaucoma requires ongoing care and commitment to treatment. Vision already lost cannot be restored, but early and consistent treatment can preserve remaining sight. People with glaucoma may need support to adapt to changes in vision, including the use of visual aids and lifestyle adjustments. Emotional support and patient education play an important role in maintaining quality of life.
Preventing Vision Loss From Glaucoma
There is no guaranteed way to prevent glaucoma, but early detection is the most effective strategy for preventing blindness. Regular eye examinations, particularly for older adults and those with risk factors, are essential. Following prescribed treatment, attending follow-up appointments, and informing close relatives about potential inherited risk all contribute to better outcomes.
Glaucoma Awareness
Glaucoma is often called the silent thief of sight because it can cause significant vision loss before a person is aware of any problem. Raising awareness encourages regular eye checks, early diagnosis, and timely treatment. With increased knowledge, accessible eye care services, and lifelong management, the burden of glaucoma-related blindness can be significantly reduced, protecting vision and independence for millions of people worldwide.