Diabetes and Eyes

Introduction:

"Eyes are the most beautiful organs created by nature which enables us to visualize things, people, animals, etc. It is an essential factor that is necessary for individuals to be independent in their life." But a lot of health conditions not associated with the eye cause complications to the eye in their advanced stages. This adversely affects the vision. Diabetes is one such condition that, when left untreated, affects the eye. Microvascular complications mostly involve eyes, kidneys, and nerves in common.

What Is Diabetes?

Diabetes is a metabolic syndrome entity that is characterized by hyperglycemia, high blood pressure, and dyslipidemia. Our body needs the energy to perform its metabolic activities that are essential for survival. This energy is derived from the food we eat in the form of glucose. This glucose from the blood is utilized by the cells. Insulin, a hormone secreted by the pancreas, promotes glucose uptake by the cells and is responsible for maintaining our blood sugar levels.

In any case, if the pancreas does not produce enough insulin or if the cells do not use the insulin, then unused glucose begins to accumulate in the blood resulting in diabetes. Over time elevated blood sugar levels cause various systemic complications.

What Are the Microvascular Complications of Diabetes?

The complications of diabetes are classified as,

• Acute - Diabetic ketoacidosis, hyperosmolar non ketosis, and lactic acidosis.

• Chronic - Macrovascular and microvascular complications.

Macrovascular complications include stroke, myocardial infarction, gangrene, etc.

Elevated blood glucose levels cause various inflammatory reactions and lipid and fibrin deposition in the blood vessels causing arterial narrowing and reduction in the blood flow to the tissues. We call it microvascular complications of diabetes.

The microvascular complications occur in three vital organs :

• Eyes - Retinopathy, glaucoma, and cataract.

• Kidney - Nodular Glomerulosclerosis, microangiopathy causing nephropathy.

• Nerves - Neuropathy with sensory and motor fibers involved, autonomic neuropathy.

How Does Diabetes Affect the Eye?

Here we shall discuss some of the ocular or visual complications of diabetes, which can cause permanent blindness if not detected and treated in time. The complications that we discuss in this article are of utter importance. They are,

• Diabetic retinopathy.

• Open-angle glaucoma.

• Cataract.

What Is Diabetic Retinopathy?

It is one of the most commonly occurring microvascular complications of diabetes leading to blindness. The blood vessels of the retina (innermost and back layer of the inside of the eye) get affected. It is also said that diabetic retinopathy can occur in people even years before being diagnosed with diabetes. It can be divided into:

• Non-Proliferative Stage - It is also known as background retinopathy or dot hemorrhages. The first sign of retinopathy is characterized by the presence of microaneurysms or small vascular dilatations in the retina, which appear as red dots in the retinal examination. These hemorrhages occur in the middle layers of the retina. The blood-retinal barrier gets compromised, leading to retinal edema, leading to visual deterioration if ignored. They appear as grey areas on the retina.

• Proliferative Stage - They appear as white areas on the retina, and this type of diabetic retinopathy occurs due to the formation of new blood vessels on the retinal surface. Continuously proliferating blood vessels can ultimately lead to vitreous hemorrhage and retinal detachment ending in vision loss.

We need to detect non-proliferative stages so that we can avoid their progression into the proliferative stage.

What Symptoms Do People With Diabetic Retinopathy Exhibit?

Diabetic retinopathy does not cause any signs or symptoms in the early stages of the disease. However, some people do experience certain on and off vision changes, such as difficulty seeing distant objects clearly or being unable to read books.

In advanced stages, there may be the appearance of dot-like or cobweb-like dark floaters. If this occurs, it is a serious sign indicative of retinal blood vessels leaking into the vitreous. Though in some cases, the floaters may resolve on their own, there are high chances of recurrence with further worsening.

What Complications Does Untreated Retinopathy Cause?

Diabetic retinopathy by itself is a serious eye condition that, when ignored, can further lead to complicated eye conditions such as,

• Retinal Detachment - Recurrent and untreated retinopathies lead to scarring of the retina. In the process, these scars tend to pull the retina leading to tractional retinal detachment.

• Diabetic Macular Edema - When the damaged retinal blood vessels leak their fluid into the nearby macula, fluid accumulation and edema of the macula take place, leading to blurry and faded vision.

• Neovascular Glaucoma - The newly proliferating retinal blood vessels cause blockage at the site where eye fluid drains, due to which aqueous outflow gets compromised. The end result is blindness. This is secondary glaucoma.

What Is Open-Angle Glaucoma?

Diabetes increases the risk of open-angle glaucoma. Open-angle glaucoma is primary glaucoma that is said to occur due to increased pressure build-up within the eye. This pressure is due to impaired drainage of eye fluid. As a result, the increased pressure pushes the optic nerve over time, damaging it. Again gradually, it ends in vision loss.

How Does Diabetes Cause Cataract?

Cataracts during old age are common, but diabetes increases your risk of developing cataracts at a younger age. Cataracts are characterized by a cloudy lens and can cause blurry vision, fading colors, diminished vision at night, double vision, a halo around lights, and often perceive sunlight or other light sources to be too bright. But leaving them untreated can lead to vision loss.

How Are Eye Problems Due To Diabetes Evaluated?

• Regular eye checkups once in 6 months need to be done, which include fundus examination and intraocular pressure estimation. Visit an ophthalmologist and ask for an eye examination (diabetic).

• If you have any complications, then there are so many treatment options available, but your ophthalmologist will advise the suitable options.

How Can Eye Diseases Due to Diabetes Be Prevented?

• Tight control of diabetes without hypoglycemia is necessary.

• Blood pressure should be controlled below 130/80 mm Hg.

• Lipids control - LDL (low-density lipoproteins) cholesterol should be targeted below 100 mg/dL.

• Initiation of antioxidants, ACE (angiotensin-converting enzyme) inhibitors, and statins. Please consult your doctor once before starting medicines, as each individual will have some contraindications.

Conclusion:

Having diabetes can increase the risk of acquiring other complications in the long run. But detecting diabetes in the early stages and keeping the blood sugar levels under control with various management methods help prevent diabetes-induced health complications. Hence, if you have diabetes, regularly schedule an eye check-up once every six months, even if your blood sugar levels are well controlled.