World Diabetes Day 2022: How Does Diabetes Lead To Eye Problems? Here's What Experts Say

World Diabetes Day: In diabetics, there is an accumulation of harmful products called glycation end products. These can damage the microvasculature of the eyes, leading to eye problems.

World Diabetes Day is observed annually on November 14 to raise awareness about diabetes and pursue efforts for the prevention, treatment and care of the disease. In 2007, the United Nations designated November 14 as World Diabetes Day to commemorate the birth anniversary of Sir Frederick Banting, a Canadian scientist who co-discovered insulin with Charles Best in 1922.

Diabetes is a disease affecting an estimated 537 million people across the world, including more than 77 million in India. It has also been associated with various kinds of eye problems. On World Diabetes Day, we discuss the science behind these eye problems, and what experts say.

Science behind diabetes leading to eye problems

In diabetics, there is an accumulation of glycation end products, which are harmful products formed when protein or fat combine with sugar in the bloodstream. These products damage the microvasculature of various organs. Therefore, the microvasculature in the retina, which includes capillaries, becomes damaged due to glycation end products. When the tiny blood vessels in the eye are damaged, fluid leaks into the retina. This results in muscular edema and leads to ischemic optic neuropathy and death of the capillaries. Ischemic optic neuropathy is the condition in which blood does not flow properly to the eye’s optic nerve. When the capillaries die, one suffers from ischemia as well as hypoxia, Dr Natasha Radhakrishnan, Clinical Professor, Ophthalmology, Amrita Hospital, Kochi, told ABP Live via mail. Hypoxia is the condition in which the cornea does not receive enough oxygen because it has no blood supply of its own. 

Hypoxia results in the release of vasoactive endothelial growth factor (VEGF), a substance that encourages the growth of new blood vessels. When blood vessels begin to form inside the retina, neovascularization occurs. This is the process by which new vascular structures assemble. In iris neovascularization, there is an abnormal blood vessel growth on the iris of the eye. All these problems can arise in diabetics if they do not maintain some precautions. 

Diabetics are also likely to get cataracts. Cataract occurs due to the hyperglycemic state, which causes glucose to enter into the lens. This causes the fibres in the eye to opacify, Dr Radhakrishnan said. 

Diabetics can also develop glaucoma, a group of eye conditions that damage the optic nerve. 

“Diabetes mellitus is a complex metabolic disorder characterised by hyperglycemia, a physiologically abnormal condition represented by continued elevated blood glucose levels,” Dr Saurabh Choudhary, CEO of ICARE Eye Hospital, Noida, told ABP Live. 

“Hyperglycemia results from anomalies in either insulin secretion or insulin action or both and manifests in a chronic and heterogeneous manner as carbohydrate, fat, and protein metabolic dysfunctions which affect multiple organs of the body and disrupt their normal functioning. The structural and functional disruptions in organ system vasculature lead to micro- and macrovascular complications. Commonly affected body organs are eyes, kidneys, heart, and nerves,” Dr Choudhary added. 

Diabetic eye problems are related to the duration of diabetes

Diabetic retinopathy is directly related to the duration of diabetes in a patient, to the control of the condition, and to risk factors such as nephropathy (deterioration of kidney function), anaemia, hypertension, smoking, obesity and dyslipidemia (imbalance of lipids such as cholesterol, LDL, HDL and triglycerides), among others. All these risk factors contribute to diabetic retinopathy in diabetics, Dr Radhakrishnan said .
Cataract is mostly related to the hyperglycemic state of the patient. The more uncontrolled the sugars are, the more the chances are for the lens to develop cataract, compared to others. 

Meanwhile, glaucoma is multifactorial. Only some diabetics are more likely to develop glaucoma, compared to others, Dr Radhakrishnan said. If one has a family history of glaucoma, they are more likely to suffer from the condition than diabetics without a family history. 

A diabetic patient can have both diabetic retinopathy and cataract, Dr Radhakrishnan said. 

When a person has diabetes at a young age, the chance of cataract formation increases by two to five times, Dr Choudhry said. 

Diabetes doubles the risk of open-angle glaucoma, a condition in which new blood vessels grow in the iris and interfere with the normal flow of fluid out of the eye. This causes pressure to build up in the eye. The pressure may damage the optic nerve, which carries signals from the eye to the brain, Dr Choudhry further said. 

Risk factors for diabetic eye problems

More than half of people with diabetes can develop diabetic retinopathy, Dr Choudhry said. Good control of diabetes can lower the risk of developing diabetic retinopathy. Women with diabetes who become pregnant or women who develop gestational diabetes are at high risk for getting diabetic retinopathy.

Poor control of blood sugar level, high blood pressure, high cholesterol, pregnancy and tobacco use are the risk factors for diabetic eye problems. 

Diabetics should undergo dilated eye examination every year to see if they have diabetic retinopathy, Dr Radhakrishnan said. If one has type 2 diabetes, they should undergo eye screening as soon as they are diagnosed because it is highly likely that the diabetes was detected late. 

If one’s sugars are uncontrolled, and they are suffering from ketoacidosis (diabetic complication resulting in the build-up of acids in the blood), they may suffer from other complications such as eye infections, or sinus infection that can spread into the eye. 

The longer the duration of diabetes, the higher are the chances of suffering from eye problems.