Diabetic Retinopathy: A Blind Diabetic as Proof of Serious Neglect of Prevention
Diabetic retinopathy is the most common cause of blindness in working-age patients in developed countries. Early detection of diabetic retinopathy offers a chance to preserve vision. Therefore, careful screening and timely initiation of treatment are crucial.
Occurrence
Diabetic retinopathy is among the microvascular complications of diabetes mellitus (DM). It is a complex affliction of the retina caused by chronic and long-term poorly controlled hyperglycemia. It is more commonly seen in patients with type 1 DM, affecting up to 70%. Among type 2 diabetics not treated with insulin, it affects just under 40%.
Etiopathogenesis
Several mechanisms of tissue damage contribute to the development of diabetic retinopathy. Non-enzymatic glycation, oxidative stress, and activation of the polyol pathway lead to increased capillary permeability. Activation of certain isoforms of protein kinase C increases the expression of vascular endothelial growth factor (VEGF).
In the preclinical stage, functional changes occur in the retina without observable structural changes. This is followed by the non-proliferative phase, characterized by the formation of microaneurysms which, when ruptured, lead to hemorrhages in various retinal layers. In the proliferative phase, ischemia of the retina results in the formation of new blood vessels. However, these new vessels are of poor quality and their rupture can lead to acute vitreous hemorrhage. Fibrosis of these vessels can also result in tractional retinal detachment.
Manifestations
In its early stages, diabetic retinopathy is often clinically silent for a long time, with any fluctuation in visual acuity attributed to changes in blood glucose levels. In advanced stages, retinal hemorrhages cause visual field defects. Diabetic macular edema manifests as a rapid deterioration of near vision (for reading). Vitreous hemorrhage leads to a severe and rapid decline in visual functions.
The Importance of Early Detection
The key preventive measure is long-term and thorough management of DM and active screening for diabetic retinopathy. Early detection of the first asymptomatic changes in the retina offers a high chance of preserving full visual functions. An ophthalmologist examines the retina under mydriasis once a year for all DM patients. The referral for this examination must include basic information regarding the patient's diabetes, including glycated hemoglobin (HbA1c), risk factors, and treatment. In the event of a positive finding, the ophthalmologist determines the content and frequency of further check-ups. Any sudden visual problems in a diabetic patient also require immediate eye examination. It is advisable for the attending physician to inform the ophthalmologist of changes in the treatment plan and to refer the patient for a preventive eye examination before and shortly after any planned change.
Treatment Options
The gold standard of treatment is timely laser photocoagulation of the retina. For macular edema, substances inhibiting VEGF (anti-VEGF agents) administered intravitreally are also used. Their use is limited by diabetological and ophthalmological indication criteria, requiring close cooperation between the attending physician and the ophthalmologist. Vitreous hemorrhage, retinal detachment, and other complicated conditions can be surgically addressed with pars plana vitrectomy.
Strict Prevention and Timely Treatment to Save Vision
The attending physician should ensure that the patient participates in regular screening examinations. The patient must be properly educated about the progression of the disease and the necessity of prevention even in the asymptomatic stage. Intervention in the presence of risk factors (hyperglycemia, hypertension, and hyperlipidemia), active screening for diabetic retinopathy, and timely specialized ophthalmological treatment are essential parts of comprehensive therapeutic and preventive procedures that reduce the risk of complete vision loss in diabetics by more than 90%.
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Sources:
1. Karen I., Svačina Š. Diabetes mellitus. 2020 Update. Recommended diagnostic and therapeutic procedures for general practitioners. Society of General Medicine ČLS JEP, 2020. Available at: www.svl.cz/files/files/Doporucene-postupy/2020/DIABETES-MELLITUS-2020.pdf
2. Češka R., Štulc T., Tesař V., Lukáš M. (eds.). Internal Medicine. 2nd, updated edition. Triton, Prague, 2015.
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