Diabetic retinopathy is a potential complication of diabetes. It is a progressive eye condition with different stages that increase in severity as more damage occurs to the retina.

Health experts may refer to diabetic retinopathy as a progressive eye disease. This refers to the fact that the condition typically worsens over time.

An eye doctor may classify the condition into two types and four stages. The two types are nonproliferative diabetic retinopathy (NPDR), which refers to the early stages of diabetic retinopathy, and proliferative diabetic retinopathy (PDR), which describes an advanced form of the condition.

This article examines the types and stages of diabetic retinopathy.

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The distinguishing feature between the two types of diabetic retinopathy is the presence of neovascularization in PDR. This is the growth of new blood vessels in the retina, usually due to diabetes.

NPDR describes the first three stages of diabetic retinopathy. Nonproliferative means there are no abnormal blood vessels in the retina.

As the disease progresses and advances through the three NPDR stages, it may evolve into PDR. This is the fourth and final stage of diabetic retinopathy and indicates the presence of abnormal blood vessels, which have a greater potential for serious visual consequences.

This is the earliest stage of diabetic retinopathy and the first indication of the eye condition. The earliest sign of mild NPDR is the presence of tiny bulges in the retina’s blood vessels.

Experts refer to these areas of swelling as microaneurysms. This stage of retinopathy is very common in people living with diabetes. Microaneurysms typically appear as small red dots in the retina and may leak small amounts of blood.

As these microaneurysms result in small amounts of fluid leaking into the retina, it may trigger swelling of the macula. This refers to the back of the retina, which helps people process what they see directly in front of them.

At this stage, a person may not notice any symptoms, as mild NPDR will not typically impact a person’s vision. A person will not usually require treatment at this stage. However, if a doctor identifies this stage, they will recommend taking steps to prevent the condition from worsening.

At this stage, blood vessels in the retina further swell, interfering with blood flow to the retina. This prevents the retina from receiving proper nourishment. While mild NPDR involves the presence of at least one microaneurysm, moderate NDPR involves multiple microaneurysms.

At this stage, if blood and other fluids accumulate in the macula, a person may notice symptoms such as blurry vision.

A 2020 retrospective study suggests a 17.6% probability for a person with moderate NPDR to progress to severe NPDR or PDR within 5 years of diagnosis.

As the condition advances, blockages occur in larger sections of blood vessels in the retina. This causes a significant decrease in blood flow to this area.

A doctor may identify severe NPDR due to intraretinal microvascular abnormalities (IRMA). This term describes abnormal branching of dilation of existing blood vessels.

The presence of IRMA represents either new blood vessel growth within the retina or the remodeling of existing blood vessels. This occurs due to low levels of oxygen in the retina due to decreased blood flow.

These blood vessels are extremely thin and fragile and can result in noticeable symptoms, such as blurry vision, dark spots, and patches of vision loss.

A doctor can categorize severe NPDR using the 4-2-1 rule, which represents:

  • hemorrhages being present in all 4 retinal quadrants
  • venous beading appearing in 2 or more quadrants
  • IRMA is present in at least 1 quadrant

PDR is the most advanced form of diabetic retinopathy. At this stage, problems with blood vessels have deprived the retina of oxygen and lead to the growth of new, fragile blood vessels. These vessels grow in the retina and the vitreous, the gel-like fluid that fills the back of the eye.

These new blood vessels often leak blood into the vitreous, which can cloud vision. Additionally, these new blood vessels can form scar tissue, which can cause problems with the macula or result in retinal detachment. This can also raise the pressure in the eye and damage the optic nerve.

At this stage, a person may experience serious complications and will require treatment to help stabilize their vision. PDR can cause severe vision loss and blindness if left untreated.

A doctor will be able to stage diabetic retinopathy during a comprehensive eye exam. For this test, an optometrist or ophthalmologist will dilate a person’s pupils so that they can have a better view of the structures inside the eye.

They will look for signs of diabetic retinopathy, such as microaneurysms, hemorrhages, and cotton wool spots. After examining the eye, they will advise whether a person requires more frequent monitoring or any treatment to manage the condition.

Click here to learn more about diabetic eye screening.

Diabetic retinopathy is a common complication of diabetes. It occurs due to damage to the delicate blood vessels present in the eye. It is a progressive eye condition that worsens over time as damage accumulates. Doctors can stage the condition depending on the signs present and the extent of damage to the retina.

Doctors can classify diabetic retinopathy into two types and four stages. This includes three stages of NPDR and one stage of PDR, which is the most advanced and severe stage of the condition.