Diabetic Retinopathy and Avastin, Lucentis (Anti-VEGF) treatments

Diabetic retinopathy is a complication of diabetes that affects the retina — the light-sensitive tissue at the back of the eye. Persistently high blood sugar levels can damage the small blood vessels that supply the retina, which can affect vision and, in advanced cases, lead to severe and permanent vision loss. It's one of the leading causes of blindness in people aged 20–64, though the outlook is generally good with early detection and appropriate treatment. Dr Zoran Aleksic diagnoses, monitors, and treats diabetic retinopathy at his rooms in Sea Point, Cape Town, and Vredenburg on the West Coast.

What Is Diabetic Retinopathy?

High blood sugar levels damage the small blood vessels in the retina over time. These vessels can swell and leak fluid, or close off entirely, starving parts of the retina of blood supply. Diabetic retinopathy develops in two broad stages:

NPDR (non-proliferative diabetic retinopathy) — the earlier stage, where blood vessels leak and the retina swells. When this swelling affects the macula (the central part of the retina responsible for detailed vision), it's called macular oedema, and is the most common cause of vision loss in people with diabetes. Blood vessels can also close off, reducing blood flow to the macula.
PDR (proliferative diabetic retinopathy) — the more advanced stage, where the retina responds to reduced blood flow by growing new, abnormal blood vessels, a process called neovascularisation. These new vessels are fragile and prone to bleeding into the vitreous (the gel-like substance filling the eye), and can form scar tissue that distorts the macula or pulls the retina away from the back of the eye (retinal detachment). PDR can threaten both central and peripheral vision.

Diabetic retinopathy often causes no symptoms in its early stages. As it progresses, patients may notice floaters, blurred or fluctuating vision, dark or blank areas in their field of vision, poor night vision, or colours appearing faded — usually affecting both eyes. The risk increases the longer someone has had diabetes: retinopathy affects up to 80% of people who have had diabetes for 20 years or more, which is why regular screening matters regardless of whether you've noticed any change in your vision.

Why Regular Screening Matters

Because diabetic retinopathy can progress silently, a dilated eye examination is recommended at least once every 12 months for everyone living with diabetes, or more frequently if your retinal findings or other risk factors call for it. Diabetic eye care works best as part of a coordinated approach between your diabetic physician or GP and your ophthalmologist, since your overall blood sugar, blood pressure, and cholesterol control all directly influence how diabetic retinopathy progresses. Optometrists and GPs are often the first point of contact for detecting diabetic retinopathy, even though further treatment usually requires an ophthalmologist.

How Diabetic Retinopathy Is Detected

Screening and diagnosis typically draw on a combination of tools:

Fundus photography — high-resolution photographs of the retina, taken with a specialised camera, allow retinal changes to be documented and compared over time, and reviewed by a specialist even at a different time or location.
Optical coherence tomography (OCT) — used to assess the severity of retinal swelling (oedema) and monitor how well it responds to treatment.
Fluorescein angiography — a dye-based imaging test used to assess the extent of retinopathy and help plan treatment.
AI-assisted image analysis — software-assisted analysis of fundus photographs helps identify which patients need to be seen urgently by an ophthalmologist ("referable") versus those who can continue routine monitoring ("non-referable"), making screening more efficient and accessible.

OxIA Screening Centre

The Eye Surgery is a registered OxIA screening centre, and Dr Aleksic is an OxIA reporting specialist. Screening can be booked directly with our rooms, or through your GP — just let the booking staff know you're booking specifically for a "OxIA diabetic screening" photography. Patients are photographed with a fundus camera, and the images are analysed to determine whether the patient is referable for further assessment or can continue routine monitoring alongside their usual GP visits. This software-assisted approach offers a more cost-effective, efficient follow-up pathway for diabetic patients who stay compliant with their recommended screening schedule. At the same screening visit and at no additional cost, patients can also be checked for other common causes of vision loss, such as glaucoma and age-related macular degeneration.

Treatment Options

Treatment depends on the type and severity of diabetic retinopathy found on screening or examination. Some patients need only regular monitoring, while others benefit from active treatment:

Intravitreal anti-VEGF injections — medications such as Avastin and Lucentis, injected directly into the eye to reduce abnormal blood vessel growth and swelling, are performed in our dedicated in-house procedure room in Sea Point.
Argon laser treatment — used to seal leaking blood vessels or prevent the growth of abnormal new vessels, performed at our dedicated laser clinic, Peninsula Eye Clinic, in Claremont. The eye is dilated and numbed with local anaesthetic, a lens is placed on the eye to help focus the laser, and the treatment itself typically takes 10–45 minutes. You'll hear clicking sounds and see flashes of light during treatment. Your vision will be blurred for a few hours afterwards due to the dilating drops, so you won't be able to drive yourself home — please arrange transport in advance. Improvement in vision, where relevant, is usually gradual and may take a few weeks to notice; if laser treatment was used to prevent bleeding rather than to treat existing swelling, you may not notice any change in vision at all, which is expected.

Your surgeon will discuss which treatment, if any, is appropriate based on your screening and examination findings, alongside general measures such as optimal blood sugar control that support any treatment you receive.

When Retinal Surgery Is Needed

Dr Aleksic is an anterior segment and refractive surgeon, and provides assessment, monitoring, and the treatments above for diabetic retinopathy. He does not perform vitreoretinal surgery (surgery on the retina and vitreous) himself — this requires a specialist retinal surgeon. This type of surgery, called a vitrectomy, may be needed when there's significant bleeding into the vitreous or a retinal detachment that can't be managed with injections, laser treatment, or monitoring alone; it involves removing the affected vitreous and replacing it with a saline solution. In these more advanced cases, Dr Aleksic works closely with, and refers patients to, appropriate vitreoretinal specialists for surgical management.

Frequently Asked Questions

What's the difference between NPDR and PDR?

NPDR is the earlier stage, where blood vessels in the retina leak and swell but haven't yet started growing new, abnormal vessels. PDR is the more advanced stage, marked by neovascularisation — the growth of fragile new blood vessels that are prone to bleeding and can lead to more serious complications, including retinal detachment.

How often should I have a diabetic eye exam?

At least once every 12 months if you have diabetes, though your surgeon may recommend more frequent checks depending on your individual retinal findings and other risk factors. Regular screening is important because diabetic retinopathy often has no symptoms until it's already advanced.

What does diabetic retinopathy screening involve?

Screening typically includes a dilated eye examination and fundus photography to capture detailed images of the retina, sometimes alongside OCT or fluorescein angiography for more detail.

What is argon laser treatment for diabetic retinopathy?

Argon laser is used to seal leaking retinal blood vessels or prevent the growth of abnormal new vessels. It's performed under local anaesthetic with your pupils dilated, and takes roughly 10–45 minutes. Because of the dilating drops, your vision will be blurred afterwards, so you'll need someone to drive you home.

Does Dr Aleksic perform retinal surgery?

No. Dr Aleksic is an anterior segment and refractive surgeon who diagnoses, monitors, and treats diabetic retinopathy with injections, laser treatment, and screening. When surgery on the retina or vitreous (a vitrectomy) is required, he works closely with, and refers to, specialist vitreoretinal surgeons.

Is diabetic retinopathy treatment covered by medical aid?

Diabetic retinopathy is a Prescribed Minimum Benefit (PMB) condition under South African medical aid regulations, so many schemes provide some level of cover, though the extent varies by scheme and treatment. We recommend confirming your specific benefits with your scheme, and our rooms can help clarify costs relevant to your treatment plan at your consultation.

If you have diabetes and haven't had a recent eye screening, or would like to discuss your diabetic eye care, book a consultation with Dr Zoran Aleksic at The Eye Surgery in Sea Point or Vredenburg.