Diabetic retinopathy: Symptoms, diagnosis and treatment in Turkey

What is diabetic retinopathy and why does it progress silently?

Diabetic retinopathy (DR) is a complication of diabetes that damages the tiny blood vessels of the retina. What makes it particularly dangerous is that it often develops without any symptoms in its early stages.

It is one of the leading causes of vision loss among working-age adults worldwide (20–74 years),according to the WHO. Yet many patients are unaware of it until their vision is affected.

In the early phase, there is no pain and no noticeable change in vision. When symptoms such as blurring, floaters, or dark spots appear, the disease is often already advanced. This is why people with diabetes are strongly advised to undergo annual eye examinations, even if their vision seems perfectly normal.

From a medical perspective, the mechanism is well established. Persistently high blood sugar damages the walls of retinal capillaries, making them leak fluid or bleed. Over time, reduced oxygen supply (retinal ischemia) triggers the release of vascular endothelial growth factor (VEGF).

VEGF stimulates the growth of abnormal, fragile blood vessels. These vessels can bleed, scar the retina, and in severe cases, lead to retinal detachment and vision loss.

Understanding the stages of diabetic retinopathy

Not all diabetic retinopathy requires the same treatment. The internationally recognised classification divides the disease into five distinct stages:

Diabetic macular oedema (DME) can occur at any stage, even in mild NPDR. It results from fluid leaking into the macula, the central part of the retina responsible for sharp vision, and is the most common cause of vision loss in diabetes. Prompt anti-VEGF treatment can often reverse the fluid accumulation and restore central vision, allowing patients to read, drive, and maintain independence.

Diagnosing diabetic retinopathy: Key tests your ophthalmologist will use

Proper diagnosis and staging are critical in diabetic retinopathy, treatment strategies differ dramatically between mild non-proliferative DR (NPDR) and proliferative disease. Istanbul's partner clinics use the same advanced diagnostic tools found in Europe's top retinal centers to ensure accurate assessment:

1. Optical Coherence Tomography (OCT): The gold-standard test for detecting diabetic macular edema (DME). OCT produces high-resolution, cross-sectional images of the retina, allowing doctors to measure retinal thickness and fluid accumulation with micron-level precision. It is non-invasive and takes less than five minutes.
2. Fluorescein Angiography (FA): A special dye is injected into the arm, which highlights retinal blood vessels in real time. FA identifies areas of leakage, poor perfusion, and abnormal new vessels (neovascularization) that OCT alone may miss, making it essential for advanced disease management.
3. Colour Fundus Photography: Standardized retinal photographs are taken to document and stage the disease according to the ETDRS (Early Treatment Diabetic Retinopathy Study) scale. These images allow ophthalmologists to track disease progression over time.
4. Fundoscopy: Direct and indirect examination of the retina, optic disc, and vitreous. This remains a routine part of every initial consultation and helps detect subtle changes that imaging might not capture.

Important clinical note: OCT alone is not sufficient for evaluating proliferative DR. Fluorescein angiography is necessary to map areas of retinal ischemia and guide laser treatments. Clinics that rely solely on OCT for advanced diabetic eye disease may not provide comprehensive care.

What are the treatment options of diabetic retinopathy in Turkey?

One of the first things patients notice during consultation in Istanbul is the level of precision before any treatment is proposed. There is no one-size-fits-all protocol.

Treatment decisions depend on several key factors: the stage of the disease, the presence of macular edema, the degree of retinal ischemia, and the patient's metabolic control.

Metabolic control: The foundation that no treatment can replace

Before any eye treatment is considered, specialists work closely with endocrinologists to stabilise blood sugar (HbA1c),blood pressure, and lipid levels.

The reality is simple: no injection or laser can compensate for poorly controlled diabetes.

The landmark DCCT study showed that reducing HbA1c from 9% to 7% lowers the risk of retinopathy progression by up to 76% — one of the most powerful findings in diabetic eye care.

Anti-VEGF injections: The current standard of care

Anti-VEGF injections (ranibizumab, bevacizumab, aflibercept) are now the first-line treatment for diabetic macular edema and proliferative retinopathy.

They work by blocking VEGF, the molecule responsible for both fluid leakage and abnormal vessel growth.

Major clinical trials (RESTORE, VIVID/VISTA, PROTOCOL T) show average gains of 8–12 letters on the ETDRS scale at 12 months. In practical terms, this often means regaining the ability to read or drive.

In practice:

• Performed under sterile conditions
• Monthly or bi-monthly follow-up depending on response
• Most patients receive 3 to 7 injections in the first year

Laser photocoagulation

Laser treatment remains a cornerstone of proliferative diabetic retinopathy management.

The Diabetic Retinopathy Study (1976) showed that panretinal photocoagulation (PRP) reduces the risk of severe vision loss by around 50% in high-risk patients.

Two main types are used today:

• Focal/grid laser: targets leaking areas in the macula (non-central edema).
• Panretinal photocoagulation (PRP): treats ischemic peripheral retina to stop abnormal vessel growth.

Modern laser systems (Pascal, Navilas) used in Istanbul allow faster, more precise, and significantly more comfortable treatments compared to older technologies.

Intravitreal corticosteroids

When anti-VEGF treatment is insufficient or not well tolerated, long-acting corticosteroid implants (such as dexamethasone) offer an effective alternative.

Their effect typically lasts 4 to 6 months and can be repeated. They are particularly useful in chronic or refractory macular edema.

Vitrectomy: When surgery becomes necessary

Vitrectomy is indicated in advanced cases, such as:

• Persistent vitreous hemorrhage
• Tractional retinal detachment
• Fibrotic membranes affecting vision

This is a surgical procedure performed under local or general anaesthesia, with a recovery period of 1 to 3 weeks.

Specialised retinal teams in Istanbul use minimally invasive techniques (23G, 25G, 27G),which reduce surgical trauma and speed up recovery.

In experienced hands, anatomical success rates exceed 90% at 3 months for vitreous haemorrhage cases.

Risks and how Turkey's specialists manage them?

Transparency about risk is a sign of medical integrity, not a reason to avoid treatment. Untreated diabetic retinopathy carries a far greater risk of blindness than any of the interventions used to control it.

What happens when you choose Turquie Santé for diabetic eye treatment?

For most patients, the process is simpler than they expect.

1. Step 1: Remote assessment (before you travel): send your OCT scans, fundus photographs, most recent HbA1c and diabetic history. A partner retinal specialist reviews your case and provides a preliminary opinion, confirming whether treatment in Istanbul is appropriate and which modality is recommended
2. Step 2: Travel and confirmation appointment: on arrival, a full clinical examination is performed, including repeat OCT and, where necessary, fluorescein angiography. The treatment plan is confirmed or refined based on the current retinal status.
3. Step 3: Treatment: anti-VEGF injections and laser procedures are typically performed on the same day as diagnosis confirmation, or the next morning. Vitrectomy is scheduled within 24–48 hours with a pre-operative assessment.
4. Step 4: Return and ongoing care: most patients fly home within two to three days of injection procedures, or after seven to ten days following vitrectomy. Your Turkish specialist provides a detailed follow-up protocol for your local ophthalmologist, and remains accessible via teleconsultation between visits.