Diabetes can lead to vision loss over time due to high blood sugar levels damaging the retina. People may not notice the early stages of diabetic retinopathy. However, in most cases, doctors can effectively treat people if they detect the eye condition early.

Diabetic retinopathy (DR) is the leading cause of blindness in working-age adults. According to the Centers for Disease Control and Prevention (CDC), diabetes is the leading cause of new cases of blindness among adults aged 18–64 years.

People with diabetes may experience hyperglycemia, or high sugar blood levels. Over time, high blood glucose levels can cause sugar to accumulate in the delicate blood vessels in the eye. This can result in damage to the retina and impact vision.

While there is currently no cure, people can take steps to manage the condition and help prevent or slow vision loss.

In this article, we will discuss how diabetes impacts vision, and the signs and stages of diabetic retinopathy.

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People with diabetes can develop several complications that impact their vision. Over time, these complications may cause some vision loss or blindness. They include:

  • Diabetic retinopathy (DR): People with DR have damage to the blood vessels in their retina resulting from high blood sugar. DR may cause:
    • blurry vision
    • empty or dark areas in vision
    • vision loss
  • Diabetic macular edema (DME): DME occurs when excess fluid builds up in the macula of a person’s eye. The macula is a central part of a person’s retina that allows them to focus and see details. DME can cause:
    • blurry or double vision
    • eye floaters
    • colors to look washed out
  • Cataracts: This term refers to a condition where a person’s eye lens becomes cloudy. High blood sugar over time causes a person’s eye lens to swell, causing them to have blurry vision. People with diabetes have an increased risk of developing cataracts.
  • Glaucoma: Having diabetes doubles a person’s risk of developing glaucoma. Diabetes can lead to damage in a person’s optic nerve at the back of their eye. This can cause gradual vision loss, beginning with peripheral vision but leading to blindness.

Initially, a person may not notice any signs or symptoms, as many people with early stage DR have no symptoms at all. However, others may begin to notice changes to their vision that come and go, such as having difficulty reading or seeing distant objects.

Doctors recommend people have regular eye exams to catch any problems early. Early treatment for a person’s DR is more effective and can prevent vision loss.

DR is a progressive eye condition with different stages. The condition advances as more damage occurs to the retina. Doctors may classify DR into two main types: Nonproliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR).

NPDR refers to the earlier stages of the condition. At this stage, the blood vessels in a person’s retina begin to weaken. The weakened blood vessels may have tiny bulges, known as microaneurysms. These bulges can leak blood and other fluids into a person’s macula. This results in swelling, which can distort vision.

People may not notice these changes to their sight. However, doctors can detect it during eye exams.

PDR refers to the most advanced stage of the condition. In PDR, a person’s retina starts growing new blood vessels, which is known as neovascularization. The new vessels often bleed into the gel between a person’s eye lens and retina, known as the vitreous.

Symptoms of advanced DR vary with the amount of bleeding and can include:

  • blurred vision
  • eye floaters, or seeing spots or dark shapes
  • difficulty seeing colors or seeing them as faded or washed out
  • empty or dark areas in vision
  • difficulty with night vision
  • vision that can change from blurry to clear

People with DR usually have symptoms in both eyes.

Click here to learn more about the differences between NPDR and PDR.

Most DR treatments can only stop a person’s vision loss from getting worse. Early detection of DR is very important to stop it from affecting the person’s vision.

In some cases, blood sugar control can bring some of a person’s vision back. If a person controls their blood sugar levels, their lens can return to its original shape. This can improve a person’s vision.

However, in many cases of advanced diabetic eye disease, while treatments can help improve vision, they may not be able to restore vision.

People with diabetes can prevent eye damage by controlling their blood sugar levels. Having high blood sugar levels affects a person’s retinal blood vessels and eye lens.

Regular dilated eye exams can detect a person’s DR before it affects their vision. Doctors can then treat the DR before it causes eye damage. Doctors recommend people have a dilated eye exam at least once a year. However, a doctor may suggest more regular tests if they feel it is necessary.

People can also lower their risk of developing diabetes-related eye conditions to prevent eye damage by:

  • stopping or avoiding starting smoking
  • being physically active
  • keeping their blood pressure and cholesterol within ranges that doctors recommend

If people notice changes in their vision, they should seek medical advice.

Potential complications resulting from diabetes can cause people to lose some or all of their vision. People with early stages of some diabetic-related eye conditions do not normally have any symptoms.

If a person does not get treatment, the advanced stages of these conditions can cause irreversible vision loss.

However, regular eye exams can detect diabetic vision conditions early. Early treatment may prevent a person from losing their vision. People with diabetes can also prevent eye damage by managing their blood sugar levels.