Diabetes is a chronic health condition that can affect the eyes in many ways. In the long run, repetitive high blood sugar levels can cause a wide range of serious health complications, including peripheral neuropathy, heart diseases, kidney failure, and others.
Diabetic eye diseases are also frequent, and diabetics are advised to have a dilated eye exam once a year.
While diabetic retinopathy and macular edema are the most common eye complications in people with diabetes, diabetes almost doubles your chances of having glaucoma.
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What is glaucoma?
Glaucoma is a serious eye condition that can cause blindness. It’s the second cause of blindness in the United States.
It damages the eye’s optic nerve that connects the eye to the brain. It usually occurs when the eye’s drainage system is blocked and fluid accumulates and creates high pressure in the eye (intraocular pressure).
There are 8 types of glaucoma, the two main ones being open-angle and closed-angle. With open-angle glaucoma, the most common type, the eye pressure increases slowly, and the vision loss is gradual. On the contrary, closed-angle glaucoma happens suddenly and requires immediate medical care.
Treatments are diverse and may include eye drops, medications, and even surgery in the worst cases.
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Glaucoma mostly affects adults but may occur in children too. While causes are still unclear, several risk factors have been identified including family history, poor vision, some medications, eye injuries, thin corneas, diabetes, high blood pressure, heart disease, and others.
Diabetic retinopathy vs glaucoma
Diabetic retinopathy and glaucoma are two different eye conditions.
Diabetic retinopathy is a frequent eye complication caused by high blood sugar. It’s a damage to the blood vessels in the eye’s retina (the back of the eye). At first, you may not have any symptoms. But when blood sugars stay uncontrolled and retinopathy progresses, it can cause blurriness, dark areas of vision, difficulty perceiving colors, and even blindness in the worst cases.
Diabetic retinopathy increases your risk of having glaucoma, as well as diabetic macular edema, and other eye issues.
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The link between diabetes and glaucoma
The relationship between diabetes and glaucoma is well understood now and scientists have proven that diabetes increases the incidence of open-angle glaucoma by 36%.
Both type 1 and type 2 diabetes can lead to open-angle glaucoma. On the contrary, closed-angle glaucoma does not have any known relation with diabetes.
Does diabetes cause glaucoma?
Yes, diabetes can cause glaucoma. Several studies have worked on the relationship between diabetes and glaucoma, and all agree that diabetes can considerably increase the risks of open-angle glaucoma.
The exact mechanisms and ways in which diabetes may cause glaucoma are yet to be understood. There are two theories on the subject.
The first one is that diabetic retinopathy is responsible for the increased risk of glaucoma. By damaging the blood vessels, retinopathy may cause abnormal blood vessels to grow in the eye, which can increase eye pressure and lead to glaucoma.
According to the second theory, glaucoma may directly be caused by high blood sugar without a necessary link with diabetic retinopathy. Repetitive high blood glucose levels are believed to increase the production of fibronectin, a multifunctional adhesive glycoprotein that plays a crucial role in wound healing. Accumulation of fibronectin in the eye may block natural drainage, leading to fluid building up and causing eye pressure and glaucoma.
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How to prevent diabetes from affecting your eyes?
Glaucoma and diabetic retinopathy aren’t the only ways that diabetes can affect your eyes and vision. Macular edema, cataracts, and blurred vision are other common diabetes eye complications.
Eye conditions like glaucoma can affect anyone with either type 1 or type 2 diabetes. The risk factor is closely related to repetitive high blood sugar levels. The longer you have diabetes and the less you control it, the more likely you are to suffer from eye issues.
Fortunately, if your blood sugar is under control, your eyes should not be affected. Thus, the best way to prevent diabetes from affecting your vision is to manage it properly. Keep your glycated hemoglobin (HbA1c) below 7%. Make nutritious and healthy meal plans, and exercise regularly.
You may not notice the first signs and symptoms of diabetic eye disease. Anyone living with diabetes mellitus should have an eye exam conducted at least once a year by an ophthalmologist. In the United States, Medicare Part B covers the cost of eye exams for diabetic retinopathy once a year if you have diabetes.
If diagnosed early enough, minor cases of diabetic retinopathy or glaucoma may be treated simply with proper diabetes management. But if left untreated and prone to aggravation, these conditions may require laser treatments, surgery, or even make you lose your sight permanently.
We hope you’ve found answers to your questions in this article. If not, please do not hesitate to place a comment below and one of our team members will reply as soon as possible.
Sources used for this article:
 Zhao YX, Chen XW. Diabetes and risk of glaucoma: systematic review and a Meta-analysis of prospective cohort studies. Int J Ophthalmol. 2017 Sep 18;10(9):1430-1435. doi: 10.18240/ijo.2017.09.16. PMID: 28944204; PMCID: PMC5596230. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5596230/
 Zhao D, Cho J, Kim MH, Friedman DS, Guallar E. Diabetes, fasting glucose, and the risk of glaucoma: a meta-analysis. Ophthalmology. 2015 Jan;122(1):72-8. doi: 10.1016/j.ophtha.2014.07.051. Epub 2014 Oct 3. PMID: 25283061.https://pubmed.ncbi.nlm.nih.gov/25283061/
 Zhou M, Wang W, Huang W, Zhang X. Diabetes mellitus as a risk factor for open-angle glaucoma: a systematic review and meta-analysis. PLoS One. 2014 Aug 19;9(8):e102972. doi: 10.1371/journal.pone.0102972. PMID: 25137059; PMCID: PMC4138056. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4138056/