All about glaucoma; symptoms, types and diagnosis of glaucoma
Glaucoma is a condition that leads to slow, but progressive loss of nerve fibres in the optic nerve. Many factors may increase the risk of this condition. If left untreated, this can lead to loss of peripheral vision (i.e. what can be seen at the sides of the visual field, rather than in the centre). In older people, glaucoma is one of the commonest causes of preventable blindness. If glaucoma progresses, it can affect all peripheral vision, then impair central vision, and -- very rarely -- may lead to very significant visual impairment. Treatments for glaucoma are aimed at bringing down the pressure in the eye to a level that is low enough to prevent harm to the optic nerve. Once the optic nerve is affected by glaucoma, lowering the pressure in the eye prevents further damage to the nerve. Damage already done to the optic nerve cannot be reversed. Screening for glaucoma is important from around age 40, every two years at least, unless you are in a higher risk group (eg Afro-caribbean race, or very strong family history of glaucoma).
Signs and symptoms of glaucoma
Symptoms of glaucoma are often absent in the early stages of the disease. Unfortunately, impaired vision is sometimes the first sign of glaucoma. Classically in angle closure glaucoma, symptoms and signs of glaucoma may include eye pain, cloudy vision, red eyes, headaches, and nausea.
How Is Glaucoma Diagnosed?
Frequent eye examinations are the best way to detect glaucoma. Your ophthalmologist will test the eye’s drainage angle, evaluate the optic nerve (ophthalmoscopy), measure eye pressure, and test the visual field of each eye (perimetry). The information from these examinations is compared at regular intervals to determine if glaucoma damage has progressed over time. Regular examinations play a critical role in the early detection of glaucoma.
Glaucoma Progression
Glaucoma typically initially affects side (peripheral) vision first. If left untreated, vision loss will continue, eventually resulting in total blindness. If glaucoma is identified early and treated appropriately, good eyesight can most likely be maintained.
Types of glaucoma.
There are several types of glaucoma, all of which affect the optic nerve. Open-angle glaucoma, the commonest form of the disease, develops when the angle between the cornea and the iris where fluid is supposed to drain from the eye is open, but the fluid drains out too slowly. Closed or narrow angle glaucoma occurs when the drainage angle is blocked by part of the iris and fluid cannot drain from the eye. Normal-tension glaucoma occurs in patients with normal intraocular pressure and is treated in the same way as open-angle glaucoma. Congenital glaucoma occurs when a child is born with a poor drainage outflow facility.
Treatment for glaucoma.
There are two main types of treatment for glaucoma: medication and surgery. Both of these treatments for glaucoma manage the disease by lowering the intraocular pressure. Medications and eye drops are common treatments, but there is the possibility of side effects, and they may eventually become ineffective over time. If the IOP cannot be managed by medications or eye drops alone, surgery or laser may be recommended. Your ophthalmologist will decide on your "target IOP" to help plan your treatment.
Recovery after Glaucoma Treatment
Glaucoma surgery is usually painless, although some patients may experience a slight stinging sensation following the procedure. Local anaesthetics are used to minimise any patient discomfort. After surgical treatments for glaucoma, it is possible to experience blurred vision or irritation. Typically, however, these effects are short-lived and normal activities, such as going to work or running errands, can be resumed after 2-3 days. This time period can be variable, it depends on the exact procedure performed.
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