Diabetic retinopathy is a specific angiopathy affecting the vessels of the retina of the eye and developing against the background of a long course of diabetes mellitus. Diabetic retinopathy has a progressive course: in the initial stages, blurred vision, a veil and floating spots in front of the eyes are noted; in the later stages, a sharp decrease or loss of vision. Diagnostics includes consultations with an ophthalmologist and a diabetologist, ophthalmoscopy, biomicroscopy, visometry and perimetry, angiography of retinal vessels, biochemical blood tests. Treatment of diabetic retinopathy requires systemic management of diabetes, correction of metabolic disorders; in case of complications – intravitreal administration of drugs, retinal laser coagulation or vitrectomy.
Diabetic retinopathy is a highly specific late complication of diabetes mellitus, both insulin-dependent and insulin-independent types. In ophthalmology, diabetic retinopathy causes visual disability in patients with diabetes mellitus in 80-90% of cases. People with diabetes develop blindness 25 times more often than other members of the general population. Along with diabetic retinopathy, people suffering from diabetes mellitus have an increased risk of coronary heart disease, diabetic nephropathy and polyneuropathy, cataracts, glaucoma, occlusion of CAC and CVS, diabetic foot and gangrene of the extremities. Therefore, the issues of diabetes mellitus treatment require a multidisciplinary approach, including the participation of endocrinologists (diabetologists), ophthalmologists, cardiologists, podologists.
The mechanism of development of diabetic retinopathy is associated with damage to retinal vessels (retinal blood vessels): their increased permeability, occlusion of capillaries, the appearance of newly formed vessels and the development of proliferative (scar) tissue.
Most patients with long-term diabetes mellitus have certain signs of fundus damage. With the duration of diabetes up to 2 years, diabetic retinopathy is detected to some extent in 15% of patients; up to 5 years – in 28% of patients; up to 10-15 years – in 44-50%; about 20-30 years – in 90-100%.
The main risk factors affecting the frequency and rate of progression of diabetic retinopathy include:
- duration of diabetes mellitus,
- the level of hyperglycemia,
- arterial hypertension,
- chronic renal failure,
- metabolic syndrome,
Puberty, pregnancy, hereditary predisposition, smoking can contribute to the development and progression of retinopathy.
Taking into account the changes developing on the fundus, there are non-proliferative, preproliferative and proliferative diabetic retinopathy.
An elevated, poorly controlled blood sugar level leads to damage to the vessels of various organs, including the retina. In the non-proliferative stage of diabetic retinopathy, the walls of retinal vessels become permeable and brittle, which leads to spot hemorrhages, the formation of microaneurysms – local bagged dilation of the arteries. Through the semipermeable walls of the vessels, a liquid fraction of blood seeps into the retina, leading to retinal edema. If the central area of the retina is involved in the process, macular edema develops, which can lead to a decrease in vision.
In the preproliferative stage, progressive retinal ischemia develops due to arteriole occlusion, hemorrhagic infarcts, venous disorders.
Preproliferative diabetic retinopathy precedes the next, proliferative stage, which is diagnosed in 5-10% of patients with diabetes mellitus. Contributing factors in the development of proliferative diabetic retinopathy include high degree of myopia, occlusion of the carotid arteries, posterior vitreous detachment, optic nerve atrophy. At this stage, due to the oxygen deficiency experienced by the retina, new vessels begin to form in it to maintain an adequate oxygen level. The process of neovascularization of the retina leads to recurrent preretinal and retrovitreal hemorrhages.
In most cases, minor hemorrhages in the layers of the retina and vitreous resolve on their own. However, with massive hemorrhages in the eye cavity (hemophthalmos), irreversible fibrous proliferation occurs in the vitreous body, characterized by fibrovascular fusion and scarring, which eventually leads to traction detachment of the retina. Secondary neovascular glaucoma develops when the outflow pathways of HCV are blocked.
The disease develops and progresses painlessly and with little symptoms – this is its main cunning. In the non-proliferative stage, the decrease in vision is not subjectively felt. Macular edema can cause a feeling of blurring of visible objects, difficulty reading or doing work at close range.
In the proliferative stage of diabetic retinopathy, when intraocular hemorrhages occur, floating dark spots and a veil appear in front of the eyes, which disappear on their own after a while. With massive hemorrhages in the vitreous body, there is a sharp decrease or complete loss of vision.
Patients with diabetes mellitus need regular examination by an ophthalmologist in order to detect initial changes in the retina and prevent proliferating diabetic retinopathy.
In order to screen diabetic retinopathy, patients undergo visometry, perimetry, biomicroscopy of the anterior segment of the eye, biomicroscopy of the eye with a Goldman lens, diaphanoscopy of eye structures, Maklakov tonometry, ophthalmoscopy under mydriasis.
The ophthalmoscopic picture is of the greatest importance for determining the stage of diabetic retinopathy. In the non-proliferative stage, microaneurysms, “soft” and “hard” exudates, hemorrhages are detected ophthalmoscopically. In the proliferative stage, the fundus picture is characterized by intraretinal microvascular anomalies (arterial shunts, dilation and tortuosity of veins), preretinal and endoviteral hemorrhages, neovascularization of the retina and DZ, fibrous proliferation. To document changes on the retina, a series of fundus photographs is taken using a fundus camera.
With opacities of the lens and vitreous body, instead of ophthalmoscopy, they resort to ultrasound of the eye. Electrophysiological studies (electroretinography, determination of CSF, electrooculography, etc.) are carried out to assess the safety or impairment of the functions of the retina and optic nerve. Gonioscopy is performed to detect neovascular glaucoma.
The most important method of visualization of retinal vessels is fluorescence angiography, which allows recording blood flow in choreoretinal vessels. An alternative to angiography can be optical coherence and laser scanning tomography of the retina.
To determine the risk factors for the progression of diabetic retinopathy, blood and urine glucose, insulin, glycosylated hemoglobin, lipid profile, etc. are examined. indicators; Doppler ultrasound of renal vessels, EchoCG, ECG, daily monitoring of blood pressure.
In the process of screening and diagnosis, it is necessary to identify changes earlier indicating the progression of retinopathy and the need for treatment in order to prevent vision loss or loss.
Treatment of diabetic retinopathy
Along with the general principles of treatment of retinopathy, therapy includes correction of metabolic disorders, optimization of control over the level of glycemia, blood pressure, and lipid metabolism. Therefore, at this stage, the main therapy is prescribed by an endocrinologist-diabetologist and cardiologist.
Careful monitoring of the level of glycemia and glucosuria is carried out, selection of adequate insulin therapy for diabetes mellitus is carried out; angioprotectors, antihypertensive agents, antiplatelet agents, etc. are prescribed. Intravitreal steroid injections are performed to treat macular edema.
Laser retinal coagulation is indicated for patients with progressive diabetic retinopathy. Laser coagulation makes it possible to suppress the process of neovascularization, achieve obliteration of vessels with increased fragility and permeability, and prevent the risk of retinal detachment.
Several basic methods are used in retinal laser surgery for diabetic retinopathy. Barrier laser coagulation of the retina involves the application of paramacular coagulates of the “lattice” type, in several rows and is indicated for non-proliferative retinopathy with macular edema. Focal laser coagulation is used to cauterize microaneurysms, exudates, and small hemorrhages detected during angiography. In the process of panretinal laser coagulation, coagulates are applied over the entire area of the retina, with the exception of the macular area; this method is mainly used at the preproliferative stage to prevent its further progression.
In case of opacity of the optical media of the eye, an alternative to laser coagulation is transcleral cryoretinopexy, based on cold destruction of pathological areas of the retina.
In the case of severe proliferative diabetic retinopathy complicated by hemophthalmos, macular traction or retinal detachment, vitrectomy is resorted to, during which blood is removed, the vitreous body itself, connective tissue cords are dissected, bleeding vessels are cauterized.
Prognosis and prevention
Severe complications of diabetic retinopathy can be secondary glaucoma, cataract, retinal detachment, hemophthalmos, significant vision loss, complete blindness. All this requires constant monitoring of patients with diabetes by an endocrinologist and an ophthalmologist.
An important role in preventing the progression of diabetic retinopathy is played by properly organized control of blood sugar and blood pressure, timely intake of hypoglycemic and hypotensive drugs.