Diabetes refers to a complex metabolic disease in which your body either can’t produce insulin, under-produces insulin, or simply can’t use it efficiently. All your body’s cells need sugar (glucose) for energy. Insulin helps to break down and deliver sugar to cells throughout your body.
Sugar levels build up in your blood if you don’t have enough insulin to break it down. This is known as hyperglycemia. Hyperglycemia can negatively affect every part of your body, including your eyes.
Blurry vision is often one of the first warning signs of diabetes. Your vision may be blurry because fluid is leaking into the lens of your eye. This makes the lens swell and change shape. Those changes make it hard for your eyes to focus, so things start to look fuzzy.
You may also get blurred vision when you start insulin treatment. This is due to shifting fluids, but it generally resolves after a few weeks. For many people, as blood sugar levels stabilize, so does their vision.
Diabetic retinopathy is a term that describes retinal disorders caused by diabetes. Some of these disorders include macular edema and proliferative retinopathy.
Macular edema is when the macula swells due to leaking fluid. The macula is the part of the retina that gives you sharp central vision. Other symptoms of macular edema include wavy vision and color changes.
Proliferative retinopathy is when blood vessels leak into the center of your eye. Blurry vision is one of the signs that this is happening. You may also experience spots or floaters, or have trouble with night vision.
Blurry vision can also be a symptom of glaucoma, a disease in which pressure in your eye damages the optic nerve. According to the National Eye Institute, if you have diabetes, your risk of glaucoma is double that of other adults. Other symptoms of glaucoma may include:
- loss of peripheral vision or tunnel vision
- halos around lights
- reddening of the eyes
- ocular (eye) pain
- nausea or vomiting
You might also have blurry vision if you’re developing cataracts. Cataracts cause the lens of your eyes to become cloudy. People with diabetes tend to develop cataracts at a younger age than other adults. Other symptoms of cataracts include:
- faded colors
- clouded or blurry vision
- double vision, usually in just one eye
- sensitivity to light
- glare or halos around lights
- vision that doesn’t improve with new glasses or a prescription that must be changed often
Although blurry vision may be a result of diabetes, there are other reasons you might have blurry vision. Some common causes include:
- dry eyes
- low blood pressure
- eye injury, inflammation, or infection
- certain prescription drugs
If you spend a lot of time in front of a computer monitor or handheld electronic device, you may find your vision getting blurry. This is called digital eye strain. Your eyes may be feeling the strain of poor lighting or the glare of the digital screen. If you’re not seated at the proper viewing distance, that can add to the problem. Other signs of digital eye strain include headache, dry eyes, and neck or shoulder pain. You may be able to correct the problem by adjusting your workspace and taking frequent breaks.
Blurred vision can also be a symptom of certain immune system disorders, such as multiple sclerosis and lupus. Treating the disease may ease symptoms like blurry vision.
If you have diabetes, you’re at increased risk for a variety of eye problems. It’s important to have regular checkups and to have your eyes examined. This should include a comprehensive eye exam, including dilation, every year.
Be sure to tell your doctor about all your symptoms, as well as all the medications you take.
Blurred vision can be a minor problem with a quick fix, such as eye drops or a new prescription for your eyeglasses. But it can also be indicative of a serious eye disease or an underlying condition other than diabetes. That’s why you should report blurry vision and other vision changes to your doctor.
In many cases, early treatment can correct the problem or prevent it from getting worse. For example, if your blood sugar is out of control, your doctor can advise you how to manage it better. However, the cause must be determined before your doctor can recommend a plan of treatment.