Diabetes

What is diabetes?

Diabetes is a chronic disease that prevents the body from making or using insulin, which leads to high sugar levels in the bloodstream.²

How does diabetes affect the eye?

Diabetes can affect the eye in many ways. People with diabetes may experience the following ocular signs and symptoms:³

• Blurry, fluctuating, double, and/or loss of vision
• Changes in glasses prescription (nearsightedness, farsightedness)
• Premature presbyopia (inability to focus on close objects)
• Early cataracts
• Glaucoma
• Paralysis of nerves in the eye (decreased corneal sensitivity)
• Retinal detachments (may be accompanied by flashes and floaters)
• Diabetic retinopathy (bleeding and swelling at the back of the eye)

What is diabetic retinopathy?

Diabetic retinopathy is a complication of diabetes in the eyes and it is one of the leading causes of blindness in Canada.⁴ 

The high blood sugar levels in diabetes can affect the blood vessels on the retina, which is the light-sensitive tissue at the back of the eye that allows us to see.⁵ This can result in diabetic retinopathy which causes bleeding, swelling, abnormal blood vessel growth, and other changes on the retina.⁵ Risk factors for developing diabetic retinopathy include high blood sugar, high blood pressure, high cholesterol, longer duration of having diabetes, and pregnancy.⁶ If diabetic retinopathy is left untreated, permanent vision loss may result.⁵

How is diabetic retinopathy treated?

Keeping a tight blood sugar control remains the cornerstone in preventing and treating diabetic retinopathy.⁶ In the early stages, diabetic retinopathy is monitored through routine eye exams. If necessary, it may be treated by eye injections with anti-VEGF (Avastin, Lucentis, Elyea) to prevent new abnormal blood vessel growth on the retina.⁶ Laser surgery may be used to help seals off leaking blood vessels.⁶ These treatments reduce swelling at the back of the eye which help to slow vision loss.⁶ Early detection and intervention of diabetic retinopathy is crucial, as treatment is much more likely to be successful at its initial stage.⁶

Can vision loss from diabetes be prevented?

Yes. Early signs of diabetes can be detected in a routine eye exam and timely management can prevent sight-threatening complications.6 However, uncontrolled blood sugar can lead to irreversible vision loss.⁶ It is important to monitor and control diabetes as much as possible to minimize the risk of developing diabetic retinopathy.

See your physician regularly and follow instructions regarding diet, exercise and medication. Visit your optometrist for routine eye exams on a yearly basis and more frequently if recommended.

References

1. Canadian Diabetes Association. (2020). Diabetes in Canada. Retrieved from Diabetes Canada: https://www.diabetes.ca/DiabetesCanadaWebsite/media/Advocacy-and-Policy/Backgrounder/2020_Backgrounder_Canada_English_FINAL.pdf
2. World Health Organization. (2016). Global Report on Diabetes. Retrieved from World Health Organization: http://docs.dpaq.de/10605-diabetes_who_embargoed-who-global-report-on-diabetes.pdf
3. Moss SE et al. Factors associated with having eye examinations in persons with diabetes. Arch of Fam Med. 1995;4(6):529-534.
4. Canadian National Institute for the Blind. (2017). Blindness in Canada. Retrieved from CNIB: https://cnib.ca/en/sight-loss-info/blindness/blindness-canada?region=on
5. Massimo P et al. Diabetic retinopathy. Diabetologia. 2002;45(12):1617-1634.
6. Mohamed Q et al. Management of diabetic retinopathy: a systematic review. Jama. 2007;298(8):902-916.