Diabetic Retinopathy: Symptoms, Stages, and When to Act

If you have diabetes and want to know what diabetic retinopathy symptoms look like — and when to act — here is a clear answer. I'm Mr Dilraj Sahota, a consultant ophthalmologist and medical retina specialist, trained at Oxford and Moorfields Eye Hospital, and diabetic eye disease is a core part of my retina practice here in the West Midlands. Below I'll cover what diabetic retinopathy does to your vision, which symptoms to watch for, and what we can do about it if problems develop. If you've had a screening result you're unsure about, you can book a consultation to have it explained properly.

Diabetic retinopathy is damage to the blood vessels at the back of the eye caused by elevated levels of sugar in the bloodstream.

The most important thing to understand is this: in the early stages there may be no symptoms whatsoever. Damage can already be occurring while your vision seems, to you, completely normal. That is exactly why the diabetic eye screening programme exists in the UK — the photographs taken at screening detect changes before you would ever notice them yourself.

When symptoms do occur, they typically include:

• Blurred or fluctuating vision
• Problems with reading
• Dark or black spots in your vision
• Shadows in your eyesight

If you have any of these, it suggests the disease has progressed — and it needs a prompt review.

The most common type — the one most people with diabetes will be affected by at some point — is background retinopathy. This is not sight-threatening and doesn't need any treatment. It can continue to be monitored through community screening; you don't need to attend hospital at this stage.

There are early vessel changes, but no threat to vision. The main thing to do is control your blood sugar, your blood pressure, and your cholesterol if it's elevated. Time is on your side with background retinopathy — keep it at this stage and your vision can be protected for years to come. But you must keep attending screening regularly.

The two stages that need prompt specialist review

• Proliferative diabetic retinopathy — new, fragile blood vessels grow at the back of the eye and are liable to bleed and damage your vision.
• Diabetic macular oedema (diabetic maculopathy) — fluid leaks into the centre of the retina and directly affects your reading vision.

These are the stages where symptoms appear, and depending on severity, treatment can be needed quite urgently.

Here's something many patients don't realise: anti-VEGF injections — the gold-standard treatment for clinically significant diabetic maculopathy — are not a last resort. They are a front-line intervention. When your vision drops to a certain level, or the fluid reaches a significant point, injections can realistically preserve and improve your vision for years to come.

Many patients assume treatment only stops things getting worse. In diabetic maculopathy, that's not the case — improvement is a genuine goal.

One thing to understand clearly: improving your HbA1c (your long-term sugar control) and your blood pressure can halt progression — but if you're already in the later stages, it may not reverse damage that's already been done. Both the medical control and the eye treatment are necessary. Neither replaces the other.

⚠️ Go to eye casualty straight away — do not wait for a GP appointment — if you have: sudden loss of vision, or a sudden shower of black blobs or red strings in your vision. This can be a severe bleed at the back of the eye called a vitreous haemorrhage, and it needs to be seen urgently, including to rule out retinal damage.

• Attend your diabetic eye screening appointments regularly. Early diabetic retinopathy has no symptoms — it has to be picked up by the screening programme.
• Ask your care team for your HbA1c, cholesterol and blood pressure figures and optimise them. They directly affect how fast retinopathy progresses and how severe it becomes.
• If screening detects diabetic maculopathy or proliferative retinopathy, ask for an urgent ophthalmology referral — you may need treatment.
• If you develop sudden black dots, a shadow across your vision, or sudden vision loss — go to eye casualty immediately.

One thing worth knowing: if your vision fluctuates through the day and your eyes feel sore and gritty, that may not be your diabetic retinopathy at all. It's more than likely a common, treatable eyelid condition — I explain it fully in my guide to blepharitis and how to treat it.

If you've been told you have diabetic changes at screening, or you'd like a specialist review of your diabetic eye health, Mr Dilraj Sahota — a fellowship-trained medical retina specialist — offers consultant-led assessment, OCT imaging and anti-VEGF treatment at:

Edgbaston Eye Consultants — 22 George Road, Edgbaston, Birmingham B15 1PJ

The Westbourne Centre — 53 Church Road, Edgbaston, Birmingham B15 3SJ

Both clinics are easily reached from Solihull, Sutton Coldfield, Harborne, Wolverhampton and across the West Midlands, with flexible appointments and online booking. Private care runs alongside — never instead of — your NHS diabetic screening, which you should continue to attend.

• Early diabetic retinopathy has no symptoms — screening is the only way it gets caught early
• Blurred or fluctuating vision, reading difficulty, dark spots or shadows mean the disease has progressed and needs prompt review
• Background retinopathy is not sight-threatening — control your sugar, blood pressure and cholesterol, and keep attending screening
• Proliferative retinopathy and diabetic macular oedema need prompt specialist care — and anti-VEGF injections can improve vision, not just stabilise it
• Medical control and eye treatment work together; neither replaces the other
• Sudden vision loss or a shower of black blobs/red strings = eye casualty immediately

Can you have diabetic retinopathy without knowing?

Yes — and this is the single most important fact about the condition. In the early stages there are often no symptoms at all, while damage is quietly occurring. That's why the UK diabetic eye screening programme photographs the back of your eyes: it detects changes before you'd notice them yourself.

Is background retinopathy serious?

Background retinopathy — the most common form — is not sight-threatening and doesn't need treatment. It's monitored through community screening rather than hospital care. The key is to control your blood sugar, blood pressure and cholesterol, and to keep attending screening so any progression is caught early.

Do anti-VEGF injections actually improve vision?

In clinically significant diabetic maculopathy, yes — they can. Anti-VEGF injections are a front-line treatment, not a last resort, and many patients see their vision preserved and genuinely improved rather than merely stabilised.

Will controlling my blood sugar reverse retinopathy?

Improving your HbA1c and blood pressure can halt progression, but in the later stages it may not reverse damage already done. That's why medical control and eye treatment work together — neither replaces the other.

What diabetic eye symptoms are an emergency?

Sudden loss of vision, or a sudden shower of black blobs or red strings in your vision. This can be a vitreous haemorrhage — a bleed at the back of the eye — and you should go to eye casualty immediately rather than waiting for a GP appointment.

Diabetic retinopathy is common — but with regular screening, good medical control, and timely treatment, your sight can be protected for years to come. If you'd like a specialist review of your diabetic eye health, Mr Dilraj Sahota offers consultant-led medical retina care in Edgbaston, serving Birmingham and the wider West Midlands. Book a consultation, or arrange a free 10-minute video call to discuss your screening result.

This article is for general information and patient education. It is not a substitute for a personal consultation, diagnosis or treatment from a qualified clinician. If you have diabetes, please continue to attend your NHS diabetic eye screening appointments, and see your optometrist or an ophthalmologist with any concerns about your vision.

Last updated: July 2026