How Fast Can Diabetic Eye Disease Progress?

Diabetic eye disease is one of the most common complications of diabetes. New Zealand diabetic retinal screening guidance estimates that around 20 to 25% of people with diabetes have some form of diabetic retinopathy, although many people are unaware that it is developing.

Diabetic retinopathy may progress slowly over many years or worsen more quickly when blood sugar levels are not well controlled. One of the biggest challenges is that early retinal damage often causes no noticeable symptoms, meaning vision can appear normal while the condition progresses.

Understanding how diabetic eye disease develops is important because early diagnosis and treatment can significantly reduce the risk of permanent vision loss.

Diabetic retinopathy is a condition caused by damage to the tiny blood vessels in the retina. The retina is the light-sensitive layer at the back of the eye that sends visual information to the brain.

Over time, persistently high blood sugar levels can weaken and damage these blood vessels, causing them to swell, leak fluid, or bleed. As the condition progresses, scar tissue can develop inside the eye and interfere with vision.

In some people, the macula also becomes swollen. The macula is the part of the retina responsible for sharp central vision used for reading, driving and recognising faces. Swelling in this area is called diabetic macular oedema and can significantly affect eyesight.

Anyone with diabetes can develop diabetic retinopathy, but the risk generally increases the longer a person has diabetes. Poor blood sugar control, high blood pressure and smoking can also increase the risk of progression.

There is no single timeline for diabetic eye disease. Some people develop only mild retinal changes that remain stable for years, while others may progress more rapidly.

In the early stages, diabetic retinopathy often develops slowly and without symptoms. However, if diabetes is not well managed, damage to the retina can worsen more quickly. Vision changes may appear suddenly once bleeding, swelling, or scar tissue becomes more severe.

Several factors can affect how quickly diabetic retinopathy progresses, including:

• How well blood sugar levels are controlled
• How long have you had diabetes
• High blood pressure or high cholesterol
• Smoking
• Pregnancy
• Existing retinal damage
• Missing regular diabetic eye checks

It is also important to understand that diabetic retinopathy does not always progress in a straight line. Some people may remain stable for long periods before the condition worsens, while others may develop complications sooner than expected.

Diabetic retinopathy generally progresses through two main stages.

Non-Proliferative Diabetic Retinopathy
This is the early stage of the disease. Small blood vessels in the retina become damaged and may start leaking fluid or tiny amounts of blood.

At this stage, most people experience no symptoms. Some may notice slight blurriness or spots in their vision, but overall eyesight typically remains fairly normal.

Even in the early stages, swelling in the macula can develop and begin affecting central vision.

Proliferative Diabetic Retinopathy
As the condition progresses, the eye attempts to replace damaged blood vessels by growing new ones. Unfortunately, these new blood vessels are fragile and prone to bleeding.

This stage is known as proliferative diabetic retinopathy. Bleeding inside the eye can cause floaters, blurred vision and sudden vision loss. Scar tissue may also form and pull on the retina, increasing the risk of retinal detachment.

Without treatment, proliferative diabetic retinopathy can lead to permanent vision loss.

One of the reasons diabetic retinopathy can be dangerous is that symptoms may not appear until the disease is already advanced.

Symptoms can include:

• Blurred or fluctuating vision
• Floaters or dark spots in your vision
• Flashes of light
• Difficulty reading or focusing
• Distorted vision
• Sudden worsening of eyesight
• Vision loss

Changes in blood sugar levels can also temporarily affect vision, which sometimes makes it difficult for people to recognise when retinal damage is developing.

Even if you do not notice symptoms, regular retinal examinations remain essential if you have diabetes.

At Auckland Eye, diagnosing diabetic retinopathy involves a thorough assessment of both your vision and retinal health.

Your ophthalmologist may recommend tests such as:

• A comprehensive eye examination
• Vision testing
• Retinal imaging and photography
• Optical coherence tomography (OCT) scans to check for macular swelling
• Eye pressure measurements
• Retinal examination using specialised lights and lenses
• Fluorescein angiography in selected cases

These tests help identify retinal damage early and allow your specialist to monitor changes over time.

Because diabetic retinopathy can progress without symptoms, regular eye checks are one of the most important ways to protect your vision.

While diabetic retinopathy cannot always be prevented completely, managing diabetes carefully can significantly reduce the risk of progression.

Keeping blood sugar levels stable is one of the most important steps in protecting retinal health. Maintaining a lower HbA1c, managing blood pressure and avoiding smoking can all help reduce the risk of vision complications.

Regular monitoring is equally important. Detecting retinal changes early allows treatment to begin before serious vision loss occurs.

People who are pregnant or have longstanding diabetes may require more frequent monitoring, as diabetic retinopathy can sometimes worsen more quickly during these periods.

Treatment depends on how advanced the condition is and whether vision has already been affected.

Anti-VEGF Injections
Anti-VEGF medications help reduce abnormal blood vessel growth and swelling in the retina. The medication is injected into the eye using local anaesthetic drops or numbing cream to minimise discomfort.

Many patients require ongoing injections over time to keep the condition stable.

Corticosteroid Injections
Steroid injections may be recommended for severe macular swelling or inflammation. These medications help reduce swelling inside the eye and may need to be repeated periodically.

Laser Photocoagulation
Laser treatment can seal leaking blood vessels and reduce the growth of abnormal vessels in proliferative diabetic retinopathy. While it is used less frequently than in the past, it still plays an important role in certain cases.

Vitrectomy Surgery
In advanced diabetic retinopathy, surgery may be required to remove blood, scar tissue or fluid from inside the eye. This procedure is called a vitrectomy.

Vitrectomy can help prevent further retinal damage and reduce the risk of severe vision loss.

Diabetic retinopathy is one of the leading causes of vision loss in adults, but early diagnosis and treatment can make a significant difference.

Many people do not realise they have retinal damage until vision changes begin to interfere with daily life. By attending regular diabetic eye examinations, retinal changes can often be detected and treated before permanent vision loss occurs.

At Auckland Eye, our specialists use advanced diagnostic technology to monitor diabetic eye disease and recommend treatment based on your individual needs.

Diabetic eye disease can progress slowly or rapidly depending on a range of factors, including blood sugar control, overall health and how early retinal changes are detected.

The most important step is not waiting for symptoms to appear. Regular eye checks, careful diabetes management and timely treatment can help protect your vision for the long term.

If you have diabetes and are concerned about your eye health, the team at Auckland Eye can assess your retinal health and recommend the most appropriate monitoring or treatment plan for your needs.