Diabetic Retinopathy

What is diabetes?

Diabetes is a disease that affects the body's ability to produce or respond to insulin, a hormone that allows blood glucose (blood sugar) to enter the cells of the body and be used for energy. Diabetes falls into two main categories: type 1, which usually occurs during childhood or adolescence, and type 2, the most common form of the disease, which usually occurs after age 45, but is increasingly being diagnosed in children and adolescents.

What is diabetic retinopathy?

Diabetes retinopathy refers to damage to the blood vessels in the eyes when the sugar levels in the blood gets too high. The blood vessels weaken and leak blood, fluid and proteins.

What are the types of diabetic retinopathy?

There are 2 main stages of diabetic retinopathy, non-proliferative diabetic retinopathy and proliferative diabetic retinopathy.

Non-proliferative diabetic retinopathy (NPDR) is an early stage of the disease where the blood vessels in the eye bleed. At this stage, vision is usually preserved. The blood vessels can also leak fluid or proteins, resulting in swelling of the retina. If the swelling happens at the centre of the retina, also known as the macula, this is called maculopathy.

Proliferative diabetic retinopathy (PDR) is a late stage of the disease where new and abnormal blood vessels are formed. These fragile vessels bleed easily and result in a leakage of blood in the eye, known as vitreous hemorrhage. With time, these vessels scar and pull the retina off the eye. This is known as a retinal detachment and often leads to blindness. If the blood vessels grow on the iris, this will lead to increased pressure in the eye known as glaucoma. This will cause pain and eventual damage to the nerve of eye.

What are the Symptoms and Signs?

In the early stages known as non- proliferative diabetic retinopathy, vision is usually not affected. At this stage, the retinopathy is often not diagnosed unless the patient goes for regular screening. When the macula gets affected, a condition also known as maculopathy, the patient will experience some blurring of vision.

In the late stage also known as proliferative diabetic retinopathy, the patient may still not experience any symptoms. The patient will experience sudden onset of severe blurring of vision or floaters when vitreous hemorrhage occurs. When retinal detachment occurs, this may be associated with increase in floaters, flashes of light or darkening of a certain portion of the vision.

How to reduce onset of Diabetic Retinopathy?

Have a healthy diet

Control blood sugar levels with regular blood sugar and HbA1c monitoring

Maintain good blood control

Exercise regularly

Stop smoking

Reduce intake of alcohol

How can I diagnose diabetic retinopathy?

Regular annual eye checks are very important. Early diabetic retinopathy is usually asymptomatic and thus often not diagnosed. However, it can be easily treated and blindness prevented. Often, when the patient experiences some symptoms, the diabetic retinopathy may be in the late stages or complicated with other conditions eg. cataract, glaucoma. At this stage, treatment is still possible but recovery may be limited.

How do I diagnose Diabetic Retinopathy?

Fundal photography can be used to capture images of the retina and document any diabetic retinopathy.

Fundal Fluorescein angiography (FFA) is a procedure that involves injection of a dye and taking multiple photos of the retina as the dye passes through the vessels. This allows identification of abnormal vessels and thus enables accurate treatment to the abnormal vascular structures.

Optical coherence tomography (OCT) is a diagnostic tool that allows a quantitative measurement of a cross-section image of the retina. This is useful for monitoring purposes as well as diagnosis for more complex cases. This also helps to measures the thickness of the retina to determine how swollen it is.

How can I treat Diabetic Retinopathy?

Early stages of diabetic retinopathy need no treatment. However, regular monitoring and preventive measures (as mentioned above) has to be taken.  Severe visual loss can be prevented if diabetic retinopathy is detected early and treated. Thus it is important for a dilated eye exam at least once a year.

1) Laser photocoagulation treatment

This involves shining a laser beam through a contact lens placed on the eye. The laser beam creates small burns on the retina to seal off abnormal blood vessels to stop it from leaking. This also prevents new vessels from growing. The whole process is usually spread out over 2-3 sessions. It does not require hospitalization and is usually not painful. The vision may be a bit blur for 1-2 days. After the whole process, the patient may experience some loss of side or night vision. Laser treatment may not restore vision that has been lost. However, this is essential to prevent further visual loss and eventual blindness.

2) Vitrectomy

When some bleeding inside the eye occurs, a procedure in the operating theatre called vitrectomy may be necessary to restore vision. This is a retina surgery where fine instruments are used to remove the blood from inside the eye. This also helps to remove scar tissue and treat retinal detachment. An air bubble may be injected at the end of the procedure to keep the eye in the normal shape. This may require the patient to maintain a facedown posture for a few days until the gas bubble disappears. Surgery usually implies a late stage of diabetic retinopathy has occurred and aims mainly to prevent further visual loss.

3) Anti-VEGFs

This is a recently discovered new group of drugs, called anti-VEGF (anti-Vascular Endothelial Growth Factor). By injecting the drug directly into the eye using a small, fine needle, it has been shown to be effective in a condition called Age-related Macular Degeneration by causing regression of the abnormal blood vessels. This has been also been used in patients with diabetic retinopathy. It can control retina swelling and prevent further bleeding in the eye. This is promising treatment that may result in improvement of vision but results vary between individuals. However, injections may have to be repeated on a monthly basis for optimal results. An example of this agent is Lucentis (ranibizumab) (www.lucentis.com). Due to the high cost of Lucentis, a close chemical alternative of Lucentis, Avastin (bevacizumab) can be used.

Avastin is a drug used for patients with colorectal cancer. It is used ‘off-label’ for patients who cannot afford Lucentis.

Both of these drugs are injected directly into the eye known as an intravitreal injection.

What can Eagle Eye Centre do for you?

At Eagle Eye Centre, we perform a complete ocular examination including visual acuity, slit lamp, intraocular eye pressure checks and dilated fundal examination. We offer a proper diagnosis and personalized treatment for your condition after your assessment.

With the latest imaging techniques including FFA, we offer an accurate diagnosis of stages of the diabetic retinopathy. In addition, we have a state-of-the-art spectral domain OCT, Zeiss Cirrus (www.meditec.zeiss.com/cirrus) which can deliver exquisite high-definition images of structures inside the eye.

We can perform laser from the latest PASCAL laser (www.optimedica.com). This is the latest and most advanced machine for precise, safe and efficient delivery of laser into the eye with less pain and side effects.

We have various intravitreal injection options between Avastin and Lucentis.

We also offer counseling with regards to diet and lifestyle modifications. We also have a wide range of low vision aids to help overcome various visual inconvenience.

Enquiries

Eagle Eye Centre Pte Ltd (EEC)

820 Thomson Road, Mount Alvernia Hospital,

Medical Centre Block B, #02-11/17,

Singapore 574623

Tel: 6456-1000 / 6eagleye (63245393)

Email: eec@eagleeyecentre.com.sg

Website: www.eagleeyecentre.com.sg

Written by: Dr Jacob Cheng, Director of Retina Services (EEC)