Eyes and diabetes mellitus & diabetic retinopathy (damage to the retina)

Eyes and diabetes mellitus – many people are unaware that visual perception can be impaired by the metabolic disease diabetes. In fact, diabetes is one of the most common causes of new blindness. This makes it all the more important to educate diabetes patients in particular, but also their relatives, about the effects of diabetes on the eyes. In this article, you will learn more about the consequences of diabetes on the eyes, the symptoms and the treatment options.

Diabetes mellitus – what is it?

Diabetes mellitus is a chronic metabolic disease that restricts the regulation of blood sugar levels in the body. A distinction is made between two types of diabetes: Type 1 diabetes and Type 2 diabetes. While type 1 diabetes is characterized by an insulin deficiency, type 2 diabetes is characterized by a reduced effect of the body’s own hormone insulin.

Consequences of diabetes

The metabolic disease diabetes mellitus can damage the organs and blood vessels in the long term. This can result in various secondary diseases. With regard to the eyes, diabetes can lead to various complications:

• Diabetic retinopathy: damage and bleeding of the retina.
• Diabetic maculopathy: water retention in the macula (macular edema).
• Glaucoma: Increased intraocular pressure – the risk of this is increased in diabetics.
• Cataracts: Clouding of the natural lens of the eye occurs more frequently in diabetics.

In general, diabetes can lead to various temporary visual disturbances due to fluctuating blood sugar levels.

Cataracts and diabetes mellitus

Cataracts lead to a wide range of symptoms due to the clouding of the lens: blurred vision, increased sensitivity to glare, blurred vision or color fading. The disease is not only more common in diabetics, but can also be observed at a younger age. There are several reasons for this:

• High blood sugar level: The metabolism in the eye is altered – this leads to an increased accumulation of sugar and its breakdown products in the lens. As a result, water is attracted and clouding occurs.
• Oxidative stress: The increased formation of free radicals damages, among other things, the cells of the lens of the eye.
• Further consequences: Diabetes causes long-term damage to small blood vessels and inhibits the supply of nutrients to the lens – increasing the risk of cataracts.

Diabetic retinopathy: a dreaded complication of diabetes mellitus

Diabetic retinopathy describes the damage to the blood vessels in the retina caused by diabetes. The blood vessels in the retina are damaged by the chronically high blood sugar level. The result: circulatory disorders and vascular changes. The blood vessels multiply abnormally and are unstable – tears quickly occur in the vessels. This causes blood and wound fluid to leak into the retina. A distinction must be made between two forms of diabetic retinopathy:

1. Non-proliferative retinopathy:

• Early stage of diabetic retinopathy
• Small hemorrhages, vascular bulges and fluid accumulation in the retina
• Usually no noticeable symptoms are caused
• Risk of macular edema is increased in this case

2. Proliferative retinopathy

• Advanced stage of diabetic retinopathy
• Pathological formation of many new blood vessels that are unstable and rupture easily.
• Possible consequences: Retinal detachment and blindness

Symptoms of diabetic retinopathy

Diabetic retinopathy often develops slowly, so that the first warning signs are often not noticed or not taken seriously. In the early stages, those affected occasionally have blurred and fuzzy vision. In addition, black dots or spots (so-called floaters) may appear in the field of vision – these are caused by minute hemorrhages in the retina. Further symptoms occur in the advanced stage:

• Sudden loss of vision
• Visual disturbances: Dark or distorted/blurred areas in the field of vision
• Difficulties with night vision
• Blindness of one eye

If you notice the symptoms of the advanced stage, it is essential that you visit an ophthalmologist. However, an ophthalmologist should also be consulted promptly at the first symptoms of the initial stage. The sooner diabetic retinopathy is diagnosed, the better it can be controlled.

Diagnosis of diabetic retinopathy

Various methods and examinations can be used to diagnose diabetic retinopathy:

• Optical coherence tomography (OCT): Imaging method for visualizing the individual layers of the retina.
• Optical coherence tomography angiopraphy: Imaging procedure in which small vessel bulges (microaneurysms) and new vessel formations become visible.
• Fluorescein angiography (FLA): The tissue perfusion of the fundus of the eye can be assessed by means of a dye examination.

Treatment options for diabetic retinopathy

In the early stages of diabetic retinopathy, there is usually no treatment. The ophthalmologist carries out more frequent checks to keep an eye on what is happening. In the early stages, special attention should also be paid to regularly monitoring blood glucose levels – this can potentially slow down the progression of retinopathy.

Proliferative retinopathy, on the other hand, must be treated. There are various options:

• Laser coagulation: Laser therapy of the retina, particularly in the case of pathological vascular neoplasms. The vessels are obliterated using a laser.
• Intravitreal injections (IVOM): Injection of VEGF inhibitors into the vitreous body of the eye. This inhibits the formation of new blood vessels.
• Vitrectomy: A surgical procedure that is considered as a last resort.

Diabetic retinopathy / Preventing eye diseases and minimizing risk factors

As a diabetic, there are a number of measures that can be taken to reduce the risk of diabetic retinopathy:

• Stable blood sugar level: The blood sugar level should be measured regularly and kept stable to prevent damage to the blood vessels.
• Blood pressure and cholesterol: Blood pressure should be kept in check. Normal blood pressure and low cholesterol levels reduce the risk of vascular damage.
• Check-ups at the ophthalmologist: Annual check-ups with a specialist are essential in order to detect changes in the eye in good time.
• Healthy lifestyle: A healthy diet and regular exercise contribute to better regulation of blood sugar levels.
• Avoid smoking and alcohol: Smoking and alcohol lead to vascular damage and should be avoided.

In addition to annual ophthalmological check-ups, it is generally important to have the first symptoms checked promptly. Early detection allows timely intervention so that the worst consequences of diabetic retinopathy – especially the dreaded blindness – can be avoided.