Diabetes causes a person's blood sugar levels to become too high.
In type 1 diabetes, the body's immune system attacks and destroys insulin-producing cells.
In type 2 diabetes, the body does not produce enough insulin or body cells do not respond to insulin, explains the NHS.
Failure to treat diabetes can lead to serious health problems, three of which are related to the eyes.
Diabetes, according to Diabetes.co.uk, is one of the key factors in the development of cataracts.
He adds: "Although the reasons are still not fully understood, people with diabetes mellitus are statistically 60 percent more at risk of developing cataracts.
"As with most diabetes complications, maintaining good blood sugar control will help reduce the risk."
Diabetic retinopathy occurs when changes in blood glucose alterations in the blood vessels of the retina cause. People with this have been found to be at increased risk for glaucoma.
Abnormal blood vessel growth blocks the natural drainage of the eye.
Glaucoma is caused by the fluid that presses on the nerve at the back of the head.
Symptoms of glaucoma include vision loss, blurred vision or a halo around it, and pain in the eye.
High blood sugar levels as a result of diabetes can cause the lens in the eye to swell, which can lead to temporary blurred vision.
These channels are caused by very low blood glucose levels.
Other blurred vision-related causes of diabetes include glaucoma and cataracts.
One way to control or prevent the development of type 2 diabetes is to have a healthy, balanced diet.
But what does it mean when the festive season is in full swing when it comes to alcoholic beverages?
You can drink alcohol, but you must be aware of how it affects your body and how this can be done is recommended by Diabetes UK.
If you want to drink, the diabetes organization recommends the best types of drinks for you.