Diabetes & your eyes
Diabetic retinopathy is a preventable cause of blindness and is reversible in the early stages. Therefore, regular eye checkups are important.
BY: Esther Low
While diabetes is a relatively well-known disease, few however have heard of diabetic retinopathy. As having diabetes can affect one’s legs, it can also affect one’s eyes. In Singapore, according to a study which was conducted on Malays in Singapore, aged 40 to 80, almost a third of all diabetics suffer from this condition (there were no further age breakdowns).
Dr Christopher Khng, medical director of Eyewise Vision Clinic, tells us more about the condition and how it should not be ignored:
What is diabetic retinopathy?
These are the changes that occur in a patient’s retina because of diabetes. Typically, they result from poor blood flow, and blood vessel blockage and closure. One typically may see fluid leakage, areas of hemorrhage, and possible proliferation of abnormal blood vessels in the retina.
Is it a reversible condition?
In its early stages, the changes are potentially reversible if the diabetes control is good. For example, some early changes called microaneurysms, or other changes like small retinal haemorrhages may heal and disappear in a few months. If the control of diabetes is good, then these heal and disappear with no new changes in the retina appearing. So it is possible to see early changes reverse with good diabetic control.
What are the signs and symptoms to look out for?
Temporary fluctuations in the clarity of the vision indicate changing sugar levels in the blood. Changes in the visual clarity suggest that diabetic control is not very good. More serious changes in the vision include spots in the vision (floaters) that may appear as cobwebs also. This may indicate bleeding into the gel cavity of the eye (vitreous). Sometimes sudden painless loss of vision may occur following the onset of lots of floaters that may result from bleeding into the vitreous. By and large, patients have no symptoms until it is too late, which is why regular eye screening is important to pick up earlier changes that can be more easily treated.
How often should one go for screening?
In patients with no diabetic retinopathy changes in the eyes, a yearly screening with your eye doctor is usually adequate. Patients with mild diabetic eye changes may need to be seen about every six to nine months. Patients with moderate changes should be seen every three to four months.
How is the screening procedure like?
In the screening process, some eye clinics put eye drops to dilate the pupils to have a look inside the eye at the retina. The doctor may use a headlamp ophthalmoscope or a table mounted slit-lamp to look inside your eyes at the retina. If the pupils are large enough, a retina photograph taken of the eye is good enough to detect diabetic changes. In this situation, no dilating eye drops are required and only retinal photographs are taken. Your doctor will determine which is the preferred method in your case.
Are those aged 50 and above with diabetes more susceptible to developing this disease, vs a diabetic below the age of 50?
The reverse is true. Younger diabetics are at higher risk of developing diabetic retinopathy, and in fact suffer a more severe form of the disease.
Are there any underlying medical/physical conditions that increase a diabetic person’s risk of developing the disease?
Patients with concurrent hypertension may increase the risk of retinopathy. Smoking would also increase the risk of developing the illness.
Do lifestyle choices (for example, sleeping late, straining one’s eyes, looking at the computer screen for extended periods, etc) play an important part in the development of the disease, or is it more a case of managing one’s blood sugar levels?
In general, lifestyle choices do not affect the development of the disease, except smoking of course. It has more to do with the sugar levels (i.e. control of the diabetes) and the length of time (years) one has had diabetes. In general, if one has had diabetes for a longer time, it becomes more likely to show changes of diabetic retinopathy.
What kinds of treatments are available for those with this condition?
Diabetic retinopathy affects both the central retina and the peripheral retina. The approach for treatment is different depending on which part of the retina is affected.
Diabetic retinopathy can cause the central retina (macula) to be swollen causing blurry vision (a condition called macular oedema/swelling). In the past, this used to be treated with a scatter laser treatment to the retinal area near the central part of the retina but sparing the actual centre itself. This is a procedure called macular grid laser. It tends to be destructive, and recently has been replaced by a more gentle and effective treatment involving injections of a drug called Lucentis. This drug specifically targets the abnormal leaking blood vessels while leaving the other normal structures alone.
If the peripheral retina shows severe diabetic changes, mainly caused by poor blood flow (called ischaemia), then another laser technique called pan-retinal photocoagulation (PRP) is required. Here, laser burns are scattered throughout the peripheral retina in a bid to lower the retinal oxygen consumption.
Patients with diabetes also get cataracts (lens clouding), which affect vision permanently unless the cataract is removed. In general, diabetics get cataracts about 10 years earlier than normal people without diabetes.
What advice would you give to someone suffering from diabetes/diabetic retinopathy?
The most important advice is to have your eyes checked regularly by an eye doctor even if you do not have any visual symptoms. Early detection can avoid the majority of the eye problems associated with diabetes.
People say the eyes are windows to the soul, but in this case the eyes also reflect the other changes in the body that occur with diabetes. By looking into the eyes, eye doctors have a good idea of what other changes are occurring in the kidneys, the brain and the heart. For example, if there are diabetic eye changes, one can be almost certain that the kidneys will also be abnormal, and may be malfunctioning, leaking protein and possibly blood cells.