written by:

There’s No Sugar-Coating the Effect Diabetes Has on Your Eyes

If you have diabetes, you’re likely no stranger to the ways it can affect your entire system. Proper management of your disease requires a close and honest relationship with your healthcare team, including your optometrist.
No matter the type of diabetes you have, you’re at a higher risk for eye complications than patients without diabetes, including vision loss. To protect your eyes, optometrists offer diabetic eye exams that take an in-depth look at your eye health specific to your disease. It’s recommended that you have a diabetic eye exam every year.

The Effect of Diabetes on the Eyes

Blood sugar levels that remain high for too long can start to affect various structures of your eyes.
In the short term, you may experience blurry vision that clears up after a week or 2 when your blood sugar levels go back to normal. This blurriness is caused by swelling in the eye’s tissues that help you focus.
If your blood sugar levels remain high over an extended period, they can damage the blood vessels in the back of the eye, which can occur even during prediabetes.
Most diabetic eye diseases begin with blood vessel problems.

Diabetic Retinopathy

At the back of your eye is a thin, light-sensitive layer of tissue called the retina. The retina receives the light that enters your eyes and translates it to electrical signals that travel along the optic nerve to the brain. The retina is supplied by delicate blood vessels that are especially affected by high blood sugar.
Diabetic retinopathy occurs when these retinal blood vessels become damaged from high blood sugar levels. During the early stages of diabetic retinopathy, blood vessels become weak, and tiny bulges (microaneurysms) may leak blood and fluid into the retina. This early stage can develop with mild or nonexistent symptoms.
If diabetic retinopathy remains untreated, it can worsen and become proliferative diabetic retinopathy. At this later stage, the retina becomes deprived of oxygen, prompting the eye to grow new, fragile blood vessels on the retina, which can extend into the vitreous, the gel-like fluid that maintains the eye’s shape. These weak, abnormal blood vessels can break and leak fluid into the vitreous, obscuring vision.
Proliferative diabetic retinopathy can cause glaucoma, and abnormal blood vessel growth can lead to scarring and, eventually, retinal detachment. You may notice changes in your vision and have trouble reading or seeing at a distance. If blood and fluid leak into your vitreous, you may see floaters, spots, or strings.

Diabetic Macular Edema

At the center of your retina is an area called the macula. The macula is responsible for your sharp central, straight-ahead vision. Diabetes can cause swelling of the macula, and high blood sugar levels can damage this delicate area. If left untreated, you may experience central vision loss or blindness.
Diabetic macular edema usually develops in those with signs of diabetic retinopathy.


Diabetes doubles your chance of developing glaucoma. Glaucoma is a group of eye diseases that progressively damage the optic nerve. This damage is most often related to increased internal eye pressure, which can occur when blood leaks into the vitreous.
Glaucoma often develops with no symptoms and can lead to irreversible vision loss and blindness.


Cataracts are the clouding of the eye’s natural lens. Cataracts most often develop slowly over time and are a standard part of aging. Nearly half the American population over 80 will experience cataracts.
Diabetes makes you more likely to develop cataracts and at a younger age. Researchers believe cataracts develop when high blood sugar levels cause deposits to build up in your eye’s lens.

What’s Involved in a Diabetic Eye Exam?

A  diabetic eye exam is designed to detect signs of damage related to common diabetic eye diseases. During an exam, your eyes are dilated to allow a wider view of your internal eyes, and your optometrist uses various diagnostic equipment and tests to check your eye health.

Slit Lamp Evaluation

A slit lamp is a special microscope equipped with a bright light. It gives your optometrist a better look at the structures of your eyes.
A slit lamp evaluation looks at your:

  • Eyelids
  • Conjunctiva
  • Iris
  • Lens
  • Sclera
  • Cornea
  • Retina
  • Optic nerve

A slit lamp evaluation can uncover signs of:

  • Macular degeneration
  • Detached retina
  • Cataracts
  • Retinal blood vessel blockages

Retinal Photo Screening

Retinal photography takes a series of high-definition, full-color images of the interior of your eye. These images are kept on your file so your optometrist can compare them over time. This gives them a better chance of noticing small changes in your eyes that could indicate a problem.

Retinal photography is used to examine your:

  • Macula
  • Retina
  • Retinal vascular system
  • Optic disc

Retinal photography can uncover signs of:

  • Glaucoma
  • Diabetic retinopathy (including macular edema and microaneurysms)
  • Macular degeneration
  • Optic atrophy
  • Cancer

Optical Coherence Tomography

Optical coherence tomography (OCT) is a non-invasive, computerized imaging tool that takes detailed cross-section pictures of the layers of your retina. These images allow your optometrist to map and measure your retinal layers, looking for abnormalities that could indicate diabetic eye disease.

OCT is used to examine your:

  • Macula
  • Retina
  • Retinal vascular system
  • Optic disc

OCT can uncover signs of:

  • Macular hole
  • Macular pucker
  • Macular edema
  • Age-related macular degeneration
  • Glaucoma
  • Diabetic retinopathy


Tonometry is a test that measures the pressure levels inside your eyes. High intraocular pressure (IOP) could be an indicator of glaucoma.

Protect Your Eyes from Diabetic Eye Disease

Don’t take any chances when it comes to diabetes and your eyes. Careful monitoring of your eye health can save your eyesight and prevent vision loss and blindness.
Your optometrist is an important part of your healthcare team. Lean on them to learn more about your eyes and how they’re affected by diabetes.

About the Author

Dr. Leslie O’Dell, FAAO is the Medical Director for Medical Optometry America – Shrewsbury and an active member of the Diabetes Coalition of York County.

Recent Posts

Diabetes can bring a variety of complications, including some challenges with one’s feet.  Nerve damage and poor circulation can lead to a …

By Ronald Bollinger   A member of the Diabetes Coalition recently mentioned a theme of Knowledge is Power.  I along with other …

Scroll to Top