What it is
In short: diabetes can damage the small blood vessels in the retina, the layer at the back of the eye that senses light. This is called diabetic retinopathy. It often causes no symptoms at first, so regular eye checks matter even when you see well.
These blood vessels can leak or become blocked. Diabetes is also linked to cataract and glaucoma, so your eye check may look at more than the retina.
Diabetic retinopathy has two main stages:
- Non-proliferative retinopathy is the early stage.
- Proliferative retinopathy can develop if the retina's blood supply becomes poor. Abnormal new blood vessels grow on the surface of the retina. They are fragile and can bleed into the vitreous, the clear gel inside the eye. Scar tissue can also form and pull on the retina.
Diabetic macular oedema is swelling of the macula, the small central part of the retina that you use for detailed vision. It is caused by fluid leaking into the macula, and it can happen at different stages of retinopathy. The swelling and the stage of retinopathy are checked separately when planning your care.
Symptoms
Early changes may cause no symptoms. Clear vision does not rule out retinopathy, which is why regular checks of the retina matter even when your glasses still seem fine. Both type 1 and type 2 diabetes can affect the retina.
When symptoms appear, they can include:
- blurred or distorted central vision
- difficulty reading
- colours looking different
- floaters or a shadow in your vision
- a sudden haze or dark moving shapes, which can be caused by bleeding
The two eyes can be affected differently.
Changes in blood sugar can also blur your focus for a while. But do not assume that new blurring is caused by your sugar levels. Have your eyes checked.
When it is urgent
Get your eye checked the same day if you notice:
- a sudden drop in vision
- many new floaters
- flashes of light
- a curtain across your sight
- a painful red eye with blurred vision
These can be signs of bleeding or another retinal problem that needs prompt care.
Call the clinic at +65 6694 0400. Outside clinic hours, call the 24-hour answering service at +65 6535 8833, or go to a hospital A&E with eye services. Do not wait for your next diabetes screening appointment.
What the assessment involves
Dr Chin will ask about your diabetes, blood sugar, blood pressure, cholesterol and any eye treatment you have had. Your vision is checked, and drops widen your pupils so that Dr Chin can examine the retina. Photographs of the retina may be taken to compare changes over time.
The drops take 20 to 30 minutes to work and blur your sight for a few hours. Allow about 90 minutes to two hours for the visit, and arrange for someone to drive you home.
An OCT scan uses light to take detailed pictures of the layers of the macula. It shows any swelling.
Sometimes a test called fluorescein angiography is needed. A dye is injected into a vein in your arm, and photographs show it flowing through the blood vessels of the retina. This helps show leaks and areas with poor blood supply. Dr Chin will explain why the test is needed, and its risks, beforehand.
A screening photograph is not the same as a full assessment. Singapore's diabetic eye screening programme uses photographs to find people who need a closer look. Being referred does not decide which treatment you need. The examination and any further tests guide that decision.
Treatment options
Looking after your general health
Some early changes only need regular checks, without any eye procedure. At every stage, looking after your blood sugar, blood pressure and cholesterol is part of the plan. Work with your diabetes doctor, and take your medicines as prescribed. Eye treatment does not replace diabetes care.
Treatments for the eye
- Anti-VEGF injections: used for macular swelling or abnormal new vessels. VEGF (vascular endothelial growth factor) is a signal in the eye that drives leaking and the growth of abnormal blood vessels. The medicine blocks it. The eye is cleaned and numbed, then the medicine is injected into it. Treatment often involves a series of appointments.
- Steroid treatment: medicine placed inside the eye, used in some situations. It can lead to cataract and raise the eye pressure.
- Laser: used to treat specific leaking spots, or to help stop fragile new vessels growing. Laser for proliferative retinopathy can affect your side vision and night vision, and Dr Chin will talk you through this trade-off.
- Vitrectomy surgery: may be suggested for bleeding that does not clear, or for scar tissue pulling on the retina.
Risks and questions
Injections and surgery have risks, including infection, bleeding and problems with the retina. Your plan depends on what is found in your eye, and on how often you would need to come back.
Good questions to ask:
- What is each treatment meant to do?
- What would regular checks without treatment involve?
- What would make us change the plan?
Recovery and follow-up
Checks continue after a course of treatment, because swelling or new vessels can come back. Vision tests, retinal examinations and scans help decide when you need to be seen next, and whether you need more treatment. If you cannot attend an appointment, call the clinic to rearrange it rather than leaving a long gap.
After a procedure, follow the instructions you are given about drops and activity. After an injection, get checked straight away if pain, redness or blurred vision gets worse. Recovery after surgery depends on the operation and the condition of your retina.
If your sight stays limited, low-vision support can help with everyday tasks such as reading, checking medicine labels and using a phone.
Related articles
Sources
- National Eye Institute: Diabetic retinopathy
- US National Institute of Diabetes and Digestive and Kidney Diseases: Diabetic eye disease
- American Society of Retina Specialists: Diabetic retinopathy
- NHS: Diabetic retinopathy
- Singapore National Eye Centre: Singapore Integrated Diabetic Retinopathy Programme