Glaucoma is an eye disease that is often associated with increased eye pressure, that causes damage to the optic nerve. The optic nerve is responsible for transmitting visual information from the eye to the brain.
Glaucoma is a leading cause of irreversible blindness worldwide. Asymptomatic in the early stages, it is often undetected until there is extensive visual field loss, hence it has been called “the silent thief of sight”.
Our eye produces a clear fluid, known as aqueous humor, that provides nutrients to the eye and maintains its shape. There is a delicate balance between fluid production and fluid drainage from the drainage angle. Glaucoma is caused by a build-up of fluid within the eye when the drainage system is not functioning properly, resulting in increased eye pressure and damage to the optic nerve.
The number of people with glaucoma in Asia is estimated to increase from 51 million in 2013 to 81 million in 2040.
Different Types of Glaucoma
Primary Open-Angle Glaucoma
Primary open angle glaucoma is the most common type of glaucoma. In this type of glaucoma, the drainage angles are open, however the drainage system is impaired. Hence, there is a build-up of fluid within the eye. It progresses slowly and has hardly any symptoms in the early stages.
Primary angle closure glaucoma
In primary angle closure glaucoma, the drainage angles are narrow or closed, and the fluid is unable to reach the drainage system, resulting in high eye pressure. Primary angle closure glaucoma is more common in Asia compared to other parts of the world.
Secondary glaucoma
Secondary glaucoma refers to high eye pressure that is caused by an identifiable cause, such as an eye injury, infection, inflammation, very mature cataract, subluxed cataract, or following an eye surgery.
Congenital glaucoma
Congenital glaucoma is a type of glaucoma that occurs in babies due to the drainage system not developing properly.
Symptoms of Glaucoma
Most forms of glaucoma develop gradually as the buildup of fluid pressure in the eye happens slowly. Patients lose their peripheral vision slowly, and central vision is usually maintained until late in the disease. The process is usually painless. Hence, most patients do not have any symptoms in the early stages of the disease. As the disease progresses, patients may develop tunnel vision, and even blindness in end-stage disease. Vision loss from glaucoma cannot be restored.
Acute glaucoma is less common, and occurs when there is a sudden severe rise in eye pressure. The symptoms include eye pain, redness, blurred vision, seeing haloes around light, and may be associated with headache, nausea and vomiting.
Risk Factors
Glaucoma can affect anyone. Although everyone is at risk of getting glaucoma, the following risk factors further increase the chance of a person getting glaucoma:
- Older age
- High eye pressure
- Family history of glaucoma
- High short-sightedness or far-sightedness
- Poorly controlled diabetes mellitus
- Long-term steroid use
- Eye injury
- Obstructive sleep apnoea
- Migraine
GLAUCOMA Screening
Glaucoma develops gradually and gets harmful eventually. During the early stages of the disease, most have only minor symptoms; they are only aware of the illness in its advanced stages. Glaucoma eye screening is extremely beneficial for those above 40 years old in detecting the condition early and initiating the best possible available treatment.
Our Glaucoma Specialist
Dr Annabel Chew
Dr Annabel Chew is the Senior Consultant Ophthalmologist at Lang Eye Centre.
She was formerly a Senior Consultant of the Glaucoma Department at the Singapore National Eye Centre (SNEC), and is currently a Visiting Consultant at SNEC. She completed her medical training with the Faculty of Medicine, National University of Singapore (NUS) in 2005. She completed her Ophthalmology residency training in Singapore and was awarded the Ministry of Health Training Award in 2010 for her specialist training. She obtained her Master of Medicine (Ophthalmology) from NUS in 2011, and her specialist accreditation in Ophthalmology. She qualified as a Fellow of the Academy of Medicine, Singapore (FAMS), and a Fellow of the Royal College of Surgeons of Edinburgh, and successfully completed her glaucoma sub-specialty fellowship training at SNEC.
Dr Chew specialises in cataract surgery and the treatment of general ophthalmology conditions including retinal and corneal diseases. She sub-specialises in glaucoma and has experience in managing patients with complex glaucoma. Her clinical interests include glaucoma lasers, trabeculectomy, tube shunt surgery, minimally invasive glaucoma surgery, cataract surgery, and implantation of toric and multifocal lenses for the correction of myopia, astigmatism and presbyopia.
Dr Chew was the Clinical Director of the Primary Eyecare Clinic and Community Eyecare clinic at SNEC. She was also the lead for community eye investigation units in the Regional Eye Service. She was instrumental in setting up the Glaucoma Observation Clinic (GLOC) at SNEC, and had overseen the planning and implementation of GLOC services at SNEC satellite sites.