Comprehensive Eye Tests
Cataract is the most common cause of blurry vision in the elderly. A cataract is a clouding of the normally clear lens of the eye and usually affect both eyes, though often at different rates. While the rate of progression is usually slow, it sometimes matures rapidly in only a matter of weeks.
Cataracts are often a part of ageing and usually starts after age 60 but for some it can start as early as age 40. Not all cataracts are age-related. Cataracts can also occur from eye injury, taking certain medications or hereditary. They tend to occur more often in patient with diabetes and high myopia.
The typical symptom of cataract formation is a slow, progressive, and painless decrease in vision. It often starts as blurring of vision when reading or in sunlight or bright lights, glare, particularly at night; frequent eyeglass prescription change; a decrease in colour intensity; a yellowing of images; and in rare cases, double vision.
The treatment for cataract is to replace the eye’s natural lens with an artificial lens made of biocompatible material such as silicone or plastic. The implanted lens is customized in terms of the lens power to manage the patient’s existing refractive errors to enable the patients to have better vision without glasses.
Glaucoma is a disease which damages the nerve to the eye (optic nerve). It is caused by an increase in eye pressure due to a block in the drainage system of the eye. As a result, the natural fluids produced by our eyes accumulate and damages the optic nerve causing blindness. It usually progresses slowly with no pain, no redness or other symptoms until an advanced stage. The term for this is chronic glaucoma. Initially, only side vision is loss but if untreated, vision is lost progressively until only a small central ‘tunnel’ of vision is left. Glaucoma affects mainly the middle-aged and elderly. As the disease is silent, it is important for those above age 45 years to have their eye pressure checked at least once a year, especially if they have family members with Glaucoma or if they have diabetes or high myopia.
In some cases, the onset is sudden and termed acute glaucoma. This is caused by a sudden rise in the internal eyeball. There is severe pain in the eye, redness and blurring or loss of vision. There may also be nausea, vomiting and a one-sided headache. Some patients may see coloured rings or haloes. If there is sudden loss of rather than blurred vision, the eye surgeon will need to exclude other causes such as retinal detachment, block of either branches of the retinal vein or artery and diabetic eye disease.
Vision loss due to chronic glaucoma is usually permanent. However, if diagnosed early, the raised eyeball pressure can usually be controlled by using pressure-lowering eye drops daily, and on the long-term. This either reduces the amount of fluid produced or assists in the flow of fluid out of the eye. It is a means of control, not cure as Glaucoma is a life-long disease. If control of the eyeball pressure cannot be maintained with eye drops, surgery or laser treatment may need to be carried out. Regular eye-checks are mandatory.
Diabetic Eye Disease
Diabetic eye disease is the leading cause of blindness in Singapore. Diabetes damages the blood vessels of the retina causing the blood vessels to leak blood and fluid into the retina. In the early stage of disease, vision is not affected unless the leakage of blood and fluid happens to involve the macula. Therefore, all diabetic patients should have their eye checked once a year by an eye doctor, even if they have no visual symptoms of blurred vision.
In more severe cases of diabetic eye disease, abnormal blood vessels start to grow on the surface of the retina. These abnormal blood vessels are fragile, bleed easily and cause scarring in the eye and blindness.
Diabetic eye disease requires a painless examination of the back of the eye. Eye drops are first used to dilate the pupils to allow the doctors to examine the retina thoroughly. A photograph of the retina is taken. Sometimes, a yellow dye is injected to do an investigation called fluorescein angiography before taking the photographs for closer analysis and management.
Early detection and prompt treatment is important. A special laser machine produces a light beam that is focused on the retina to seal the leaking blood vessels or destroy the diseased portion of the retina to stop the growth of the abnormal new vessels.
If laser treatment cannot be used a surgical procedure, called vitrectomy, will allow the surgeon to operate directly on the retina within the eyeball itself. About 60% of these patients will have improved vision following the operation. In the past, these eyes would have been lost. Life-long follow-up of patients with diabetic eye disease is important to prevent a recurrence.