Diabetic retinopathy is a lesion of the capillaries, arterioles, and venules of the retina, which is manifested by the development of microaneurism, hemorrhages, and the presence of exudative changes. And also the proliferation of newly formed vessels. Three stages of diabetic retinopathy are distinguished: nonproliferative, preproliferative, proliferative.
In diabetes mellitus, vasoconstriction is observed, which is accompanied by the development of hypoperfusion. Degenerative changes in the vessels with the formation of microaneurysms occur. During the progression of hypoxia, vascular proliferation is observed, as a result of which fatty degeneration of the retina and deposition of calcium salts in it develops. Lipid deposition in the retina leads to the formation of dense exudates. The appearance of proliferating vessels is accompanied by the formation of shunts, the functioning of which causes dilatation of the retinal veins, which aggravates its hypoperfusion. The so-called stealing phenomenon is developing. This leads to the progression of ischemia retina, which resulted in the formation of infiltrates and scars. When the process is far gone, retinal detachment may occur. Aneurysm ruptures, hemorrhagic heart attacks and massive vascular invasion lead to vitreous hemorrhages. If proliferation of the iris vessels develops, this leads to secondary glaucoma.
The clinical picture depends on the stage of diabetic retinopathy. The non-proliferative stage is characterized by the appearance in the retina of microaneurysms, small-point hemorrhages and hard exudative foci. There is swelling of the retina. The retinal detachments are located in the center of the fundus or along the large veins and are represented by small dots, strokes or dark round spots. Exudates are usually localized in the central part of the fundus and have a yellow or white color.
The preproliferative stage is characterized by the appearance of pronounced oscillations in the caliber of retinal vessels, their doubling, tortuosity, and loopiness. There is a large amount of exudates, both hard and soft. The appearance of a large number of hemorrhages in the retina is characteristic, with some of its parts losing blood supply due to thrombosis of small vessels. The proliferative stage is characterized by the formation of new vessels in the retina, which are thin and fragile. This leads to the frequent occurrence of recurrent hemorrhages in the retina. As this stage progresses, germination of the newly formed vessels in the vitreous is noted.
These changes lead to hemophthalmus and the formation of vitreoretinal cords, which causes retinal detachment and the development of blindness. New vessels that form in the iris are often the cause of secondary glaucoma.
To confirm the diagnosis of diabetic retinopathy, it is necessary to conduct a series of studies, both objective and instrumental. Research methods include external eye examinations, the determination of visual acuity and visual fields research, using the slit lamp of the cornea, the razuzhka and the angle of the anterior chamber of the eye to determine the level of intraocular pressure. In case of opacities of the vitreous body and lens, an ultrasound of the eye is performed. If necessary, fluorescein angiography and fundus photography are performed.
The main principle in the treatment of this complication is to achieve compensation of metabolic processes in diabetes. Laser blind retinal photocoagulation is performed to prevent blindness. This technique can be used at any stage of diabetic retinopathy, but the greatest effect is achieved when used at early stages. The purpose of this technique is to stop the functioning of the newly formed retinal vessels. If diabetic retinopathy has already reached the proliferative stage, then the method of transconjunctival cryocoagulation can be used. If diabetic retinopathy is complicated by hemophthalmus, then vitrectomy is possible at any stage — removal of the vitreous and vitreoretinal cords.