Patients with diabetes have an increased risk of blindness to those without. Fortunately, most patients who have their diabetes well-controlled may develop nothing more than minor eye disorders. Dr Brian Kramer, specialist physician/endocrinologist at the Centre for Diabetes and Endocrinology discussed common types of diabetes related eye disorders and ways in which patients can care for their eyes.
“Diabetic retinopathy is a general term for all disorders of the retina (the light-sensitive membrane at the back of the eye) caused by diabetes. There are two major types of retinopathy: non-proliferative and proliferative,” said Dr Kramer.
- Non-proliferative retinopathy: This is the most common form of retinopathy where capillaries in the back of the eye balloon and form pouches. Non-proliferative retinopathy can pass through three stages, namely mild, moderate, and severe as a result of blood vessel blockage. “Although retinopathy does not usually cause vision loss at this stage, the capillary walls may lose their ability to control the passage of substances between the blood and the retina. Fluid can leak into the part of the eye where focusing occurs, the macula. When the macula swells with fluid, it results in a condition called macular oedema, vision blurs and can be lost entirely,” explained Dr Kramer. “Although non-proliferative retinopathy usually does not require treatment, macular oedema must be treated. Fortunately, treatment is usually effective at stopping and sometimes reversing vision loss,” he said.
- Proliferative retinopathy: For some patients, this form of retinopathy develops over several years. “Blood vessels are so damaged they close off. In response, new blood vessels start growing in the retina. These new vessels are weak and can leak blood, blocking vision – a condition called vitreous haemorrhage. The new blood vessels can also cause scar tissue to grow. After the scar tissue shrinks, it can distort the retina or pull it out of place – this is called retinal detachment,” Dr Kramer explained. The retina can be badly damaged before a patient notices any change in their vision. “Most people with non-proliferative retinopathy have no symptoms. Even with proliferative retinopathy, the more dangerous form, patients sometimes have no symptoms until it is too late to treat them. For this reason, patients should have their eyes examined regularly by an eye care professional.”
There are several factors that determine whether a patient develops retinopathy or not. These include blood glucose control, blood pressure levels, how long they’ve have had diabetes, and genetics. “The longer a patient has had diabetes, the more likely they are to have retinopathy,” said Dr Kramer. “Almost everyone with type 1 diabetes will eventually have non-proliferative retinopathy, and most patients with type 2 diabetes will also get it. But the retinopathy that destroys vision, proliferative retinopathy, is far less common. Remember, patients who keep their blood glucose levels close to normal are less likely to develop retinopathy, or if they do, they will have milder forms.”
Many patients without diabetes develop cataracts, but patients with diabetes are more likely to develop this eye condition, more specifically at a younger age where it only progresses faster. “With cataracts, the eye’s clear lens clouds, blocking light. To help deal with mild cataracts, you may need to wear sunglasses more often and use glare-control lenses in your glasses. For cataracts that interfere greatly with vision, doctors usually remove the lens of the eye and sometimes the patient gets a new transplanted lens. In people with diabetes, retinopathy can get worse after removal of the lens, and glaucoma may start to develop,” said Dr Kramer.
“People with diabetes are 40% more likely to suffer from glaucoma than people without diabetes. The longer someone has had diabetes, the more common glaucoma is. Glaucoma occurs when pressure builds up in the eye. The pressure pinches the blood vessels that carry blood to the retina and optic nerve. Vision is gradually lost because the retina and nerve are damaged,” explained Dr Kramer. There are several treatments for glaucoma, some include drugs to reduce pressure in the eye, while others involve surgery.
TIPS ON TAKING BETTER CARE OF THE EYES
It is important that patients with diabetes take precautions to help reduce their risk of developing eye problems. “Most importantly, they should keep their blood glucose levels under tight control. High blood glucose levels may also make one’s vision temporarily blurry. Bring down high blood pressure as it can make eye problems worse.
“Advise patients to see an eyecare professional at least once a year for a dilated eye exam, advised Dr Kramer. “Having a general practitioner examine the eyes is not enough. Only optometrists and ophthalmologists can detect the signs of retinopathy and only ophthalmologists can treat retinopathy.” In addition, patients should visit an eyecare professional if they experience any of the following:
- Vision becomes blurry
- Trouble reading signs or books
- Double vision
- Painful eyes
- Eyes get red and stay that way
- Experience pressure in the eye
- See spots or floaters
- Straight lines do not look straight
“Patients who are between the ages of 10 and 29 and have had diabetes for at least five years should have an annual dilated eye exam. Those who are 30 or older should have an annual dilated eye exam, no matter how short a time they’ve had diabetes. More frequent exams may be needed if the patient has an eye disease. Lastly, dilated eye exams are important for patients who are pregnant or are planning to get pregnant,” said Dr Kramer.