Diabetes: Why does a lack of glycemic control pose a risk to the retina?

The increase in blood glucose causes alterations in blood vessels and, at the ocular level, the passage of fluid into the retina. With consequences that can reach the loss of vision.

More than 300 million people suffer from diabetes today. And, according to some estimates, these numbers will increase by 50% over the next 15 years.

We speak of a chronic disease, from which one does not recover, but which can be kept under control with adequate therapy. As with many other diseases, early diagnosis is crucial. Especially since the long-term damage of undiagnosed diabetes can be very serious.

An example is diabetic macular edema, the leading cause of vision loss in the working population.

What is diabetic macular edema?

It is an accumulation of fluid in the macula, the central area of the retina, fundamental for the vision of colors and fine details. Fluids arrive from the capillaries that normally carry nourishment to the cells of the retina.

However, abnormal blood sugar levels can alter the permeability of the wall of these vessels, causing fluid to be released in the central area of the retina, resulting in swelling of the macula.

There are several types of macular edema:

• focal, i.e. localized only in certain points of the retina, is associated with problems with individual blood vessels
• diffuse, characterized by generalized fluid loss by many of the capillaries of the retina
• cystoid, with the formation of numerous cysts, due to the insinuation of liquid between the different layers of the macula, moving them apart.

What does diabetes have to do with it?

Diabetes is a disease caused by the body’s inability to transport glucose from the blood to the cells of the real organs. Over time, the accumulation of this sugar in the blood can trigger the excessive production of certain substances, such as VEGF (vascular endothelial growth factor).

This molecule acts on the wall of blood vessels, regulating their permeability: when it is present in excessive quantities, the vessels become much more permeable and allow the passage of too much fluid from the blood to the tissues. If this happens at the level of the capillaries that are located in the retina, we witness the formation of macular edema.

About one in three people with diabetes experience vision problems related to diabetes. Problems that can be accentuated in the presence of factors such as:

• high blood cholesterol
• high blood pressure.

Diabetic macular edema is the most serious retinal problem related to diabetes. Not only that, the risk of developing this complication increases with the duration of diabetes. In other words, “long-term” diabetics have a high probability of developing macular edema.

How to spot it?

Diabetic macular edema is manifested by symptoms such as:

• blurred vision
• Image warping
• loss of contrast
• altered color perception.

All this makes it difficult to perform any daily activity that requires separate vision, such as reading, writing or driving the car. To make the diagnosis certain, in addition to a thorough eye examination, it is necessary to undergo specialized examinations, such as fluorescence angiography and optical coherence tomography (OCT), which can assess the state of health of the retina in terms of thickness and vascularization.

Can it be prevented?

The first thing to do is to monitor your blood glucose level with periodic tests. Detecting diabetes early allows you to take the necessary precautions to safeguard not only your eyesight, but also the functionality of other organs, such as the kidneys, which are also affected by circulation problems caused by this disease.

For those suffering from diabetes, it will be sufficient to undergo periodic checks by the ophthalmologist to identify any disorders in the bud and immediately resort to the most appropriate therapy.