Can Diabetes Damage My Eyes If My Blood Sugar Is Controlled? By Dr Rupal Morjaria

You take your medication.

You attend your diabetes reviews.

Your blood sugar readings may seem relatively well controlled.

So it can come as a surprise to hear that changes are still developing at the back of your eyes.

One question patients understandably ask is:

“Can diabetes still damage my eyes if my blood sugar is controlled?”

Good blood sugar control is extremely important and can help reduce the risk of diabetic eye disease. However, it does not mean that your risk disappears completely.

Diabetes can affect the small blood vessels within the retina over time, and several factors beyond your current blood sugar reading can influence your eye health.

As a Consultant Ophthalmologist and Medical Retina Specialist, I regularly assess and treat patients with diabetic eye disease. Understanding what is happening inside the eye is important, particularly because retinal changes can sometimes develop before you notice a significant difference in your vision.

How Does Diabetes Affect The Eyes?

At the back of your eye is a light sensitive layer of tissue called the retina.

The retina contains a network of very small blood vessels.

Over time, diabetes can damage these blood vessels, causing them to become weakened, blocked or leaky.

This is known as diabetic retinopathy.

In its earlier stages, you may not notice any change in your eyesight at all.

As the condition progresses, however, changes within the retina can begin to threaten your vision.

This is one reason why monitoring your eyes remains important even when your vision feels completely normal.

Can Diabetic Retinopathy Develop Even If My Diabetes Is Controlled?

Yes, it can.

Managing your blood sugar well can significantly reduce your risk of developing diabetic retinopathy and can help slow its progression.

However, diabetic eye disease is influenced by more than a single blood glucose reading.

Your overall risk can be affected by factors including:

• How long you have had diabetes

• Your blood sugar control over time

• Your blood pressure

• Your cholesterol

• Kidney disease

• Pregnancy

• Smoking

• Existing changes within the retina

This means somebody can be doing many of the right things with their diabetes management and still require careful monitoring of their eyes.

Good diabetic control remains extremely valuable, but it should work alongside regular eye screening rather than replace it.

Does Having Diabetes For Longer Increase My Risk?

Yes.

The length of time you have been living with diabetes is an important factor in the development of diabetic retinopathy.

The longer the small retinal blood vessels are exposed to the effects of diabetes, the greater the opportunity for changes to develop.

This does not mean that everyone who has had diabetes for many years will experience serious sight problems.

It does mean that continuing to look after both your general health and your eyes remains important throughout your life with diabetes.

Can Diabetes Damage My Eyes Without Me Knowing?

Yes, and this is one of the most important things to understand about diabetic eye disease.

Early diabetic retinopathy may not cause noticeable symptoms.

You may still be:

• Reading normally

• Driving normally

• Working without difficulty

• Seeing clearly with your glasses

• Experiencing no eye pain

Yet changes may already be developing within the retinal blood vessels.

Waiting until your eyesight deteriorates is therefore not a reliable way of knowing whether diabetes is affecting your eyes.

Regular diabetic retinal screening is designed to identify these changes before you necessarily become aware of them yourself.

What Is Diabetic Macular Oedema?

Diabetes can also affect the macula, the central part of the retina responsible for detailed vision.

If damaged retinal blood vessels begin to leak fluid, this can cause the macula to swell.

This is known as diabetic macular oedema.

You may notice:

• Blurred central vision

• Difficulty reading

• Distorted vision

• Reduced fine detail

• Colours appearing different

• One eye seeing differently from the other

  
  

Diabetic macular oedema can occur at different stages of diabetic retinopathy and may require specialist treatment.

What Is Proliferative Diabetic Retinopathy?

When diabetic retinopathy becomes more advanced, areas of the retina may not receive enough oxygen because of damage to its blood supply.

The eye can respond by developing new, abnormal blood vessels.

This is called proliferative diabetic retinopathy.

These new vessels are fragile and can bleed into the eye.

In more advanced cases, scar tissue can also develop and potentially pull on the retina.

This is why identifying and managing diabetic retinopathy before serious complications develop is so important.

Is Blood Sugar The Only Thing I Need To Control?

No.

Blood sugar management is central to diabetes care, but your wider cardiovascular health also matters.

Blood pressure and cholesterol are particularly important because diabetes already places stress on the small blood vessels throughout the body, including those within the retina.

Working with your diabetes or primary care team to manage:

• Blood glucose

• Blood pressure

• Cholesterol

• Smoking

• Kidney health

• General cardiovascular health

Managing these factors effectively can play an important role in protecting both your eye health and your overall health.

Is Diabetic Eye Screening Still Important If My Vision Is Fine?

Absolutely.

One of the main purposes of diabetic eye screening is to identify retinal changes before they begin causing obvious symptoms.

Having clear vision today does not necessarily tell us that the retina is completely unaffected.

Screening allows changes to be detected and monitored so that patients can be referred for specialist assessment when appropriate.

It is therefore important to continue attending the diabetic eye screening appointments offered to you, even if:

• Your diabetes feels well controlled

• Your glasses prescription has not changed

• You have no eye symptoms

• Your eyesight seems perfectly normal

  
  

Screening and routine diabetes care each have different but complementary roles.

What Happens If Diabetic Eye Disease Is Found?

Finding diabetic retinopathy does not automatically mean that you need treatment.

The appropriate next step depends on the type and severity of the retinal changes.

Some patients may simply require monitoring.

If diabetic macular oedema or more advanced diabetic retinopathy develops, treatment may be recommended.

Depending on the individual condition, this can include:

• Intravitreal eye injections

• Retinal laser treatment

• Closer specialist monitoring

• Management of underlying health risk factors

  
  

The aim is to protect vision and reduce the risk of further retinal damage wherever possible.

Can Eye Injections Help Diabetic Eye Disease?

For some patients, yes.

Anti VEGF injections are commonly used to treat diabetic macular oedema.

These medicines are injected into the eye and work by reducing the effects of VEGF, a protein involved in blood vessel leakage and abnormal blood vessel growth.

Treatment can help reduce fluid within the macula and protect or improve vision in suitable patients.

Some people require a course of injections followed by ongoing monitoring, with further treatment depending on how their eye responds.

The treatment plan should always be tailored to the individual patient and the changes occurring within their retina.

When Should I Have My Eyes Checked?

If you have diabetes, attending your recommended diabetic eye screening remains important even when you have no symptoms.

You should also seek advice if you notice a new or unexplained change in your vision.

Symptoms worth investigating include:

• Increasingly blurred vision

• Distorted or wavy vision

• Difficulty reading

• A noticeable difference between your eyes

• New floaters

• Changes in your central vision

• Dark or missing areas within your vision

Some visual symptoms require more urgent assessment.

Sudden loss of vision, a sudden shower of new floaters, flashing lights, significant eye pain or a new curtain or shadow across your vision should be assessed urgently.

The Bottom Line

Good blood sugar control can significantly reduce the risk of diabetic eye disease, but it does not mean that your eyes no longer need monitoring.

The key points to remember are:

• Diabetes can damage the small blood vessels within the retina.

• Good blood sugar control is an important part of reducing your risk.

• Your blood pressure, cholesterol and duration of diabetes also matter.

• Diabetic retinopathy can develop before you notice changes in your vision.

• Clear eyesight does not necessarily mean that the retina is unaffected.

• Regular diabetic eye screening remains important even when your diabetes is well managed.

• Treatment is available for certain complications of diabetic eye disease.

• New or sudden changes in vision should not be ignored.

So rather than asking:

“My diabetes is controlled, so are my eyes safe?”

A more useful question may be:

“What can I do to keep protecting my eyes from diabetes?”

Considering Your Next Step

If you have diabetes and have been told that there are changes at the back of your eye, or you have noticed a change in your vision, a specialist retinal assessment can help establish what is happening.

During a consultation, I can assess your vision, examine the retina and macula and, where appropriate, use detailed retinal imaging to understand the extent of any diabetic eye disease.

The aim is to identify how diabetes is affecting your eyes, explain the findings clearly and determine whether monitoring or treatment is appropriate.

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