A well-controlled metabolism is the key to preventing eye diseases. Although diabetes is no longer the most common cause of blindness in adulthood, it is still very prevalent.
Worldwide, there are approx. 35% of people with diabetes have diabetic retinopathy; in Germany, this affects between 20 and 30%. After long duration of diabetes, up to 60% of people with diabetes may develop retinopathy. These figures show that there has been an improvement through various measures over decades, but there is no reason to sound the all-clear.
Studies by major health insurance companies now show that only one third of all people are examined by an ophthalmologist after being newly diagnosed with type 2 diabetes, and that after about 2 years of diabetes only half are examined. This is contrary to the scientific guideline Diabetic Retinopathy and Maculopathy. Also, the Gutenberg Health Study shows, in people whose type 2 diabetes was newly discovered through screening, more than 1 in 5. already showed retinal changes. Lack of information and training, as well as long waiting times for appointments and examinations, are repeatedly cited as major obstacles to regular eye examinations in line with guidelines.
The most common ocular complication of diabetes is retinopathy. Basically all cells of the retina can be disturbed or even destroyed by diabetes. The changes in the smallest blood vessels are most visible to the ophthalmologist. They become increasingly permeable to blood and blood components, perish elsewhere and show the smallest vascular malformations, the microaneurysms.
The early stages of diabetic retinopathy usually progress without symptoms. This means that the people affected do not have any symptoms that indicate the development of retinal damage, and therefore they are not warned. Regular eye examinations are the only way to detect the changes at an early stage. Early diagnosis is important because the earlier treatment begins, the better the results.
Diabetic maculopathy, in which the point of sharpest vision in the center of the retina (macula) is damaged, occurs much less frequently (in less than 1% of people with diabetes). Fatty deposits and swelling of the retina (macular edema) lead to progressive loss of central visual acuity, so that those affected can no longer read or drive a car. Eye diseases such as glaucoma are also. Cataracts occur frequently in people with diabetes.
The following risk factors increase the likelihood of developing diabetic retinopathy:
– Duration of diabetes – Long-term elevated blood glucose level (HbA1c> 7 %) – Increased blood prere (> 140/80 mmHg) – presence of renal impairment – age – smoking
Although it is known since the introduction of insulin pump therapy that acute rapid lowering of blood glucose can lead to temporary worsening of an existing retinopathy. Recently, however, this phenomenon has also been observed in other medical procedures, e.g., in the treatment of diabetic maculopathy.B. after bariatric surgery or after administration of so-called GLP-1 receptor agonists.
The common factor in all these deteriorations is,
– that the diabetes had been present for a long time (usually more than 10 years) – that retinopathy had been previously diagnosed – that the mean blood glucose, measured by HbA1c, had decreased within a few weeks by 1.5-2% decrease in blood prere.
Thus, if such a significant improvement in metabolic status is sought, and it is not known whether diabetic retinopathy is present, the appropriate ophthalmologic examinations should be performed BEFORE such measures are taken.
Prevention and treatment of diabetes-related eye diseases
1. Prevention and therapy in the early stage
The best prevention against secondary damage to the eye is:
– In type 1 diabetes, the first priority is good glycemic control (HbA1c less than or equal to 7%). – In type 2 diabetes, the first priority is good blood prere control (less than/equal to 140/80 mmHg). – Avoidance of excessive alcohol consumption and smoking
If detected early, eye diseases can be stopped. Ophthalmologists can treat vascular malformations. Detect minute hemorrhages. Every affected person should therefore have regular examinations of the fundus of the eye. Depending on the personal risk profile, examinations should be performed more frequently or less frequently than once a year.
2. Symptoms of the advanced phase of diabetic retinopathy
– The retina forms new vessels to compensate for the poor blood supply. These vessels are inferior, leaky, and tear easily. – Vision deteriorates. – The new vessels sometimes grow into the vitreous body of the eye. Bleeding foci develop, which affected persons perceive as black spots "sooty rain").
3. Therapy in the advanced stage
– In proliferative diabetic retinopathy, the so-called panretinal laser coagulation is primarily used. Ingrown blood vessels are sclerosed with the laser. The therapy is reliably effective, but brings side effects such as night blindness and reduced peripheral visual field. – In the meantime, however, there is also a treatment method for this form of advanced retinopathy: intravitreal administration of VEGF antibodies, in which an inhibitor of the VEGF growth factor is injected directly into the eye. This method does not cause the side effects mentioned above, but it is only partially effective and not in all patients. The long-term effects are also not clear. – In cases of impending retinal detachment and blindness, the vitreous body of the eye is surgically removed and replaced with transparent material. – Intravitreal administration of VEGF antibodies has been used as standard therapy for diabetic maculopathy for several years. The therapy is particularly effective when the macula is thickened and the visual acuity is still maintained to some extent. Preparatory examinations, multiple injections and frequent checks and injections during the course of the treatment are necessary. In cases where anti-VEGF therapy does not work well, special forms of the hormone cortisone can be applied locally, or laser can be used.
Increased sensitivity to light in diabetes-related eye disease
Basically, increased sensitivity to light is a symptom that can occur in many eye diseases. In people with diabetes, it is found in the following contexts:
– wetting disorders of the ocular surface ("dry eye"), which occur somewhat more frequently than in people without diabetes – cataracts, which occur somewhat earlier and more pronounced than in people without diabetes – diabetic maculopathy and retinopathy, if edema of the central retina occurs or in the case of extensive scars after laser coagulation.
Source: H.-P. Hammes, K. Lemmen, "Diabetes and eye diseases. German Health Report Diabetes, S.