Diabetes mellitus is a very dangerous and progressive disease that affects all human organs and systems. Over time, blood vessels, kidneys, nervous and reproductive systems suffer. The organs of vision are affected by negative changes. A particular companion to this diagnosis is diabetic cataract. This pathology is characterized by clouding of the lens. The disorder manifests itself in varying degrees. It is natural for older people; in young people it occurs due to injuries or diabetes.
Causes of diabetic cataracts
Pathology is a complex of changes in the structure of the lens that develop due to impaired carbohydrate metabolism in the body. The second type of diabetes mellitus is accompanied by damage to the natural optical lens more often than the first type of the disease. The rapid development of diabetic cataracts begins with an increase in blood glucose levels.
If the patient takes insulin, the clinical picture of the pathology appears at an earlier period. It is caused by insulin deficiency and chronic hyperglycemia. The risk of developing lens opacities depends on how long the patient has had diabetes. The longer he suffers from this disease, the higher the likelihood of changes in the structure of the lens. The chain of pathological processes starts with a sharp transition from oral hypoglycemic medications to injectable insulin. Visual impairment can be avoided with timely treatment of carbohydrate metabolism dysfunction.
Drugs that can provoke hyperglycemia
Corticosteroids
Glucocorticosteroids can antagonize the action of insulin and stimulate gluconeogenesis, especially in the liver, leading to an overall increase in glucose production [1]. With normal carbohydrate metabolism, this property of steroids is not accompanied by changes in glycemia: the beta cells of the pancreas are able to produce sufficient amounts of insulin to compensate for excess glucose. However, in diabetes mellitus, when insulin levels are reduced and tissue sensitivity to it is impaired, the body is not able to neutralize the effect of steroids on glucose metabolism. Therefore, while taking corticosteroids with concomitant hyperglycemia in patients with diabetes or prediabetes (impaired glucose tolerance), blood glucose levels may increase and the need for insulin or oral antidiabetic drugs may increase [1, 2].
The severity of the hyperglycemic effect varies among corticosteroids, with prednisolone and dexamethasone having the most potent effects. However, there are limitations to systemic administration of most steroids [3].
Restrictions:
- Prednisolone, methylprednisolone, dexamethasone and betamethasone are contraindicated for use in diabetes mellitus
- Hydrocortisone is prohibited for decompensated severe diabetes
- Triamcinolone is approved for disorders of carbohydrate metabolism, however, the instructions for use emphasize the likelihood of developing diabetes mellitus while taking the drug [3].
Atypical antipsychotic drugs
Drugs in this group are quite widely used to treat schizophrenia and more common mental disorders, such as recurrent depression. They can exhibit a number of serious side effects, including impaired glucose metabolism. Its severity can be so great that while taking antipsychotics, there is a possibility of developing diabetes mellitus or even diabetic ketoacidosis [1].
It is believed that hyperglycemia while taking antipsychotics develops due to changes in the regulation of glucose and insulin levels, as well as disorders of lipid metabolism. The ability of drugs in this group to stimulate appetite and promote weight gain plays a certain role. With increasing weight, the volume of adipose tissue sharply increases, which leads to a decrease in insulin sensitivity and, as a consequence, to the development of diabetes mellitus [4]. It is known that with every kilogram of excess weight, the risk of type 2 diabetes increases by 4.5% [4].
It should be noted that the severity of the negative effect of atypical antipsychotics on carbohydrate metabolism varies. Olanzapine is associated with the highest risk of impaired glycemia. Risperidone and quetiapine are considered “intermediate” risk drugs, and aripiprazole and ziprasidone have the least effect on carbohydrate metabolism [2, 4].
Restrictions
Olanzapine is prescribed with caution in diabetes mellitus. Other atypical antipsychotics, including clozapine, are used without restrictions according to the instructions [3].
Thiazide diuretics
Thiazide (hydrochlorothiazide) and thiazide-like diuretics are widely used to treat arterial hypertension, including in patients with diabetes mellitus. They are prescribed despite the fact that these drugs contribute to the development of hyperglycemia, and in some cases even induce the development of new cases of diabetes mellitus [1].
Hyperglycemia while taking diuretics of this group develops due to the implementation of several mechanisms. First, the drugs cause hypokalemia, which increases transport across beta cell membranes, leading to impaired insulin secretion. Secondly, against the background of their intake, the renin-angiotensin-aldosterone system is activated and, as a result, blood flow in the striated muscles worsens and glucose utilization decreases. This contributes to hyperglycemia and increased insulin resistance [1].
However, there is some good news. Firstly, the effect of drugs of this series on the level of glycemia is dose-dependent, and for the treatment of arterial hypertension they are used in low dosages. And secondly, the thiazide-like diuretic indapamide has virtually no negative effect on glucose metabolism, and its use in diabetes mellitus reduces the likelihood of hyperglycemia to zero [1].
Restrictions
- Hydrochlorothiazide - contraindicated in diabetes mellitus
- Chlorthalidone - contraindicated in severe forms of diabetes mellitus
- Indapamide - used with restrictions for diabetes mellitus in the stage of decompensation. The importance of monitoring blood glucose concentrations in all patients with diabetes, especially in the presence of hypokalemia, is emphasized [3].
Statins
Statins are key drugs used to prevent cardiovascular diseases. Undoubtedly, they are prescribed for diabetes, despite their so-called diabetogenic effect. Research results indicate that statins can cause the development of diabetes. However, the hyperglycemic effect of statins is quite “modest”: for the development of one case of diabetes mellitus, it is necessary to treat 167 patients with rosuvastatin at a dose of 20 mg for 5 years [1].
The negative effect on glucose levels and the possibility of increased glycemia during use are already included in the instructions for the use of statins [1]. Unfortunately, this side effect is characteristic of the entire class of drugs, and there is no difference in the severity of the hyperglycemic effect among its different representatives.
The mechanism of development of the diabetogenic effect of statins is combined. The drugs suppress insulin secretion by reducing the sensitivity of beta cells to glucose and reduce insulin sensitivity in muscles. The diabetogenic effect of statins is dose dependent: the risk of developing diabetes increases with increasing dosages.
It is noteworthy that the likelihood of diabetes when taking lipid-lowering drugs of the statin group is not increased in all consumers. The risk of a hyperglycemic effect is much higher with increased blood glucose levels, increased triglycerides, obesity (BMI ≥30 kg/m2), hypertension and old age. The increased risk of statin-induced diabetes is also associated with a number of other factors, including the female gender of the patient [1].
Despite the proven diabetogenic effect, statins continue to be used in patients with diabetes, since it is obvious that the risk of developing diabetes while taking them is completely offset by the benefit - a significant reduction in the likelihood of developing cardiovascular diseases and complications.
Restrictions
There is no guidance on the use of statins for diabetes, but the instructions emphasize the possibility of developing type 2 diabetes mellitus while taking the drugs [3].
A nicotinic acid
Vitamin PP, or niacin, is involved in many redox reactions, the formation of enzymes, and the metabolism of lipids and carbohydrates in cells. The drug is converted in the body into nicotinamide, which is involved in the metabolism of fats, proteins, amino acids, purines, tissue respiration and biosynthesis processes.
The negative effect on glycemia is expressed in the ability to increase the level of plasma glucose and glycated hemoglobin due to the development of insulin resistance and a decrease in insulin secretion by pancreatic beta cells [1]. For a person suffering from diabetes, this effect can be critical.
Restrictions
If you have diabetes, it is prohibited to take nicotinic acid in high doses. It is also considered inappropriate to prescribe a drug for the correction of dyslipidemia in cases of impaired carbohydrate metabolism. The instructions also note that nicotinic acid can reduce the hypoglycemic effect of glucose-lowering drugs [3].
Signs of cataracts in diabetes
Symptoms depend on the stage of the underlying disease. The initial stage of diabetes development may be accompanied by a slight deterioration in vision or its preservation in full. Some patients note that they have become better able to see objects located at close range.
As soon as the amount of cloudiness increases, patients complain of dots or floaters in front of the eyes, increased sensitivity to light. They lose clarity of vision due to interference appearing in the field of view. When looking at a light source, multi-colored rainbow circles appear. An alarm bell will be the appearance of a yellowish tint in all objects.
The mature form of diabetes mellitus is accompanied by a sharp decrease in visual acuity. Patients lose the ability to navigate space and take care of themselves in everyday life. Relatives notice that the color of the pupil changes. Through the lumen of its hole you can see the optical lens, which becomes cloudy and acquires a whitish tint. The use of glasses or contact lenses does not compensate for visual dysfunction. Patients claim that they see a little better, but their vision continues to “fall”. In diabetics, both eyes are affected to varying degrees.
Drops for eye cataracts in type 2 diabetes mellitus
The main function of the lens is to refract light rays so that they fall directly on the retina. Only in this case does a person have normal vision. This natural lens is naturally clear, but when cataracts occur, it begins to become cloudy. The more severe the diabetes, the cloudier the lens becomes. A radical way to get rid of this is the procedure of lensectomy, that is, replacing the natural lens, which has lost its properties, with an intraocular lens, which will ensure normal functioning of the eye.
But in the early stages of diabetes, timely therapy will stop damage to the lens. In addition, surgical intervention cannot be performed on all people due to the presence of third-party contraindications. These are the drops used to treat cataracts in diabetics.
- "Katalin." They prevent the processes of sedimentation of protein deposits and the formation of insoluble structures in the lens.
- “Potassium iodide” strengthens the local immunity of the organs of vision, promotes the breakdown of protein deposits and has a strong antimicrobial effect.
- "Katachrome". Effectively moisturize the eyes, protect them from negative influences, stimulate metabolic processes, and help remove free radicals from the tissues of the eye structures. The drops protect the lens from destruction and promote the regeneration of its damaged cells, which is important for developing cataracts.
Classification of lens opacities
A person with diabetes develops two types of lens opacities: true and senile cataracts. The first type occurs as a result of carbohydrate metabolism disorders, the second becomes a companion of old age and natural aging processes in the body. Diabetic cataracts are divided into several types, which transform into each other over time:
- initial;
- immature;
- mature;
- overripe.
In type 1 or type 2 diabetes, clouding of the lens develops very quickly. The choice of treatment method and the prognosis for recovery depend on the stage of development of the cataract. In no case should you wait until the cataract matures; loss of time threatens a complete loss of visual function.
Diabetic retinopathy as one of the most common complications of diabetes mellitus
In type 1 diabetes mellitus, diabetic retinopathy
(retinal damage) occurs more often than with type 2 diabetes mellitus, and over time leads to significant weakening of vision or complete blindness. As a microvascular complication of diabetes mellitus, diabetic retinopathy is characterized by changes in the retina, active growth of newly formed vessels, and pathological processes in the area of the macula (macula).
According to the World Health Organization, the clinical course of diabetic retinopathy is divided into a number of stages:
1. Non-proliferative stage
. At this stage, an ophthalmological examination of the eyes may reveal microaneurysms, which are capillary walls protruding in the form of sacs, dilatation of the eye veins and the formation of venous loops. During this period, with preserved central and peripheral vision, a reduced level of color perception, a decrease in contrast sensitivity, and a low level of adaptation to darkness are objectively revealed.
2. Preproliferative stage
. Changes in the fundus and retina at this stage are more pronounced. Small hemorrhages, soft and dense exudates, and swelling of the corpus luteum area appear on the retina. This stage is characterized by abnormalities of the veins and capillaries of the retina. Some areas of the retina are completely deprived of blood supply due to blockage of small vessels by blood clots. Due to the involvement of the corpus luteum in the process, a decrease in visual acuity is noted at this stage.
3. Proliferative stage
. Many new fragile vessels appear on the retina and optic nerve head, which rupture and form new hemorrhages affecting the vitreous body. At the site of hemorrhages, connective tissue grows, which over time leads to retinal detachment and ruptures, as a result of which the patient may go blind.
Treatment of diabetic cataracts
Conservative therapeutic methods in the form of eye drops can only slow down the process of lens clouding for a while. However, such treatment methods are not able to completely correct the situation. Patients diagnosed with diabetes mellitus undergo surgery to restore vision.
The method of phacoemulsification of the lens is often used. It involves crushing the natural lens with the subsequent installation of an intraocular one. The surgeon helps the patient choose the type of IOL depending on the severity of the disease and associated disorders. With the help of an intraocular lens, you can not only restore vision, but also correct various refractive errors. Artificial lenses help correct astigmatism, nearsightedness and farsightedness.
It is best to have surgery when the cataract is in its early or immature stages. In this case, the patient retains all reflexes of the fundus, there are no obstacles to a full diagnosis. Mature and overripe cataracts require the use of increased ultrasound energy. This increases the load on the eye tissue, which carries certain risks.
In diabetes, all blood vessels are very weak, so it is not advisable to carry out such a surgical intervention. With mature cataracts, the ligaments of Zinn weaken and the capsule of the optical lens becomes very thin. During surgery, it may rupture, which complicates IOL implantation.
At what sugar levels should cataracts be removed?
In people with diabetes, blood sugar levels are constantly changing. To ensure that no complications arise during surgery, as well as during the rehabilitation period, it is necessary to normalize it. At least 2 weeks before the proposed procedure, a clinical blood test is taken, and medications are prescribed to reduce alarming indicators.
Cataract removal is recommended when the sugar level is 6.0-8.0. Low levels can provoke hemorrhage, regardless of the size of the incision on the surface of the eyeball. The operation is performed on an outpatient basis; a few hours after its completion, the patient can go home, accompanied by loved ones. Before the procedure, the patient must take glucose-lowering medications in the form of tablets or inject insulin in their usual dosage. After this, you need to have breakfast to avoid hypoglycemia.
Patients are advised to bring approved foods with them to the clinic to consume after the procedure. Long waits for your turn, stress and increased nervousness can also cause hypoglycemia, so people with this diagnosis are operated on first. The doctor monitors your health after IOL implantation, prescribes a treatment regimen during the recovery period, and gives recommendations for a speedy recovery
What should a diabetic do to avoid dry eye syndrome and its complications?
Let us give you some advice:
- First, listen to yourself. Any new sensations, and especially visual discomfort, are a reason to see an ophthalmologist. You should not ignore preventive examinations, even if nothing hurts.
- Secondly, monitor your blood sugar. It needs to be constantly monitored, glycated hemoglobin and other tests taken, and regular visits to the doctor. Uncontrolled “jumps” in sugar gradually disrupt the functioning of all organs, including affecting vision.
- Thirdly, do not play roulette with food and medicine. Only a low-carbohydrate diet, careful taking of medications, and giving up bad habits can help a diabetic keep the disease “in control,” that is, compensate, and not allow complications to develop, including “dry eye” and retinal damage.
Features of preoperative preparation
Before the operation, the patient undergoes a thorough examination by an otolaryngologist, dentist, endocrinologist and therapist. Lens phacoemulsification is not performed without the permission of these specialists. Blood tests can rule out the presence of hepatitis and HIV infection, and also check the speed of blood clotting. An electrocardiogram is required to assess heart function.
Contraindications to surgical intervention include diagnosed lens subluxation and severe renal failure. Cloudiness of a large area of the optical lens complicates the ophthalmoscopy procedure. If it cannot give a real picture of the condition of the lens, an ultrasound B-scan is performed. During this procedure, the presence of secondary diseases is determined and possible complications are predicted.
