Glaucoma is the second largest cause of blindness and the main cause of irreversible blindness globally. It is caused by an increase in eye pressure, which causes gradual damage to the optic nerve that conveys visual impulses to the brain – any damage to the optic nerve results in vision loss.
The number of people with glaucoma in Asia is estimated to increase from 51 million in 2013 to 81 million in 2040.
Usually, the ailment progresses slowly and insidiously, and the individual is generally unaware of the condition until it is too late. When one experiences a symptom, there is generally already moderate to severe nerve damage. This is why the condition is known as the “quiet thief of sight”.
The eye continuously produces a clear fluid in the eye, which flows out of the eye form the drainage angle. Glaucoma is caused by a build-up of fluid within the eye.
Different Types of Glaucoma
Glaucoma usually progress slowly, with the most prevalent kinds being Primary Open-Angle Glaucoma and Chronic Angle-Closure Glaucoma. These commonly afflict those in their 40s or 50s. Glaucoma can be inherited, which means that relatives of glaucoma patients are at a higher risk.
Primary Open-Angle Glaucoma
In many countries, Primary Open-Angle Glaucoma is the most commonly found. 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.
Chronic Angle-Closure Glaucoma
In this type of glaucoma, the drainage angles are narrow or closed preventing the fluid from reaching the drainage system. This in turn results in a build-up of fluid within the eye. Asians are prone to having angle-closure glaucoma, with Singapore having the world’s highest documented incidence of it. In chronic form, this type of glaucoma develops gradually, similar to Primary Open-Angle Glaucoma, and often goes unrecognised for a long time. It is caused by increasing obstruction of the eyeball’s drainage pathways, resulting in a prolonged rise in eye pressure.
Acute Angle Closure Glaucoma
This kind of glaucoma typically affects middle-aged or older women. It is caused by a blockage of the fluid drainage pathway in the angle of the eye. This results in a fast rise in fluid pressure within the eye. The symptoms are sudden and dramatic, and requires the individual to seek immediate medical intervention.
Glaucoma can also develop when the eyeball gets inflamed or when a cataract becomes too advanced and large. Other causes of secondary glaucoma are having undergone eye surgery or an eye injury.
Symptoms of Glaucoma
Because peripheral vision is impaired first and the disease progresses slowly, people with Primary Open-Angle Glaucoma and Chronic Angle-Closure Glaucoma frequently have no symptoms in the early stages. Most people do not realise they have glaucoma until blurring of vision occurs and their central vision begins to deteriorate. By then, there may have already been considerable permanent nerve damage. Blindness occurs at end-stage glaucoma.
On the other hand, Acute Angle-Closure Glaucoma causes significant eye pain, redness, blurring, and the appearance of haloes around lights. When this happens, the individual should seek immediate medical attention.
Be aware of the following glaucoma risk factors:
- High eye pressure
- Over 60 years old
- A family history of glaucoma
- Diabetes and excessive blood pressure
- Excessively high or low short- or long-sightedness.
- A history of eye injuries or certain types of eye surgeries
- Long term steroid use
- Obstructive sleep apnoea
Pay close attention to your eye health and have regular comprehensive eye exams as recommended by your eye doctor to lower your chances of developing chronic glaucoma.
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.