Diabetic retinopathy overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Rohan Bir Singh, M.B.B.S.[2] Priyamvada Singh, M.B.B.S. [3]; Cafer Zorkun, M.D., Ph.D. [4]
Overview
Diabetic retinopathy is the most severe form of the several kinds of ocular complications causing damage to the retina, as a result of diabetes.It is an ocular manifestation of systemic disease which affects up to 80% of all diabetics who have had diabetes for 15 years or more. It is the leading cause of non traumatic blindness in adults. People with untreated diabetes are 25 times more at risk for blindness than the general population. Despite these intimidating statistics, research indicates that at least 90% of these new cases could be reduced if there was proper and vigilant treatment and monitoring of the eyes.
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Normal vision. Courtesy NIH National Eye Institute
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The same view with diabetic retinopathy.
Historical Perspective
Although diabetes was a well-known disease as from the 2nd century AD, no clinician attempted to link this endocrine disorder with eye-pathology before the middle of the 19th century. In 1846, the French ophthalmologist and Professor of Hygiene in Paris, Appolinaire Bouchardat (1806-1886), reported the development of visual loss in the absence of cataract in diabetics. This was partly reversible and in most cases improvement was associated with better control of diabetes. A few years later, François Tavignot made similar observations.[1] However, no histopathological specimens were examined and the implication of macular disease in diabetes remained tentative until the invention of the ophthalmoscope.
Jäger had inexhaustible patience and exemplary precision in ophthalmoscopy and, in illustrating his findings, meticulously incorporated the smallest details into his pictures. He used the newly developed direct ophthalmoscope in order to produce one of the first atlases containing 21 colour plates of fundus paintings, which were drawn after 20-40 clinical sessions per patient. He described ‘roundish’ or oval, yellowish spots and full or partial thickness extravasations through the retina in the macular region of a diabetic patient.[1] His findings were controversial at the time and Albrecht von Graefe (1828-1870) claimed that there was no proof of a cause-effect relationship between diabetes and retinal complications. Von Graefe’s scepticism was adopted by many of his colleagues, with the exception of Louis Desmarres (1810-1882) in 1858.
No further evidence was presented until 1869, when Henry Noyes (1832-1900) published an article in the USA supporting the link between diabetes mellitus and maculopathy. His observations were confirmed in 1872 by Edward Nettleship (1845-1913) in London, who expanded on this theme in his paper entitled ‘On oedema or cystic disease of the retina’ and presented the first histopathological proof of a cystoid degeneration of the macula in diabetic patients.Five years later, Nettleship published another article with Sir Steven Mackenzie (1791-1868), which described in detail the abnormal retinal changes induced by diabetes. n 1876, Wilhelm Manz (1833-1911) published his seminal paper on ‘Retinitis proliferans’ containing several drawings of fibrovascular degeneration of the optic disc and vitreoretinal adhesions in the retina. Fourteen years later, in 1890, Julius Hirschberg (1843-1925) classified diabetic retinopathy into four types (retinitis centralis punctuate, haemorrhagic form, retinal infarction, and haemorrhagic glaucoma), thus describing the full natural history of diabetic retinopathy. The descriptive term, diabetic retinitis, though erroneous since the disease is not of inflammatory origin, continued to be used for several years.
At the beginning of the 20th century there was still the unresolved debate as to whether macular changes were directly related to diabetes or whether they were caused by atherosclerosis and hypertension. Arthur James Ballantyne (1876-1954) of Glasgow suggested that diabetic retinopathy represents a unique form of vasculopathy and his work showed for the first time the role of capillary wall alterations in the development of diabetic retinopathy, as well as the presence of deep waxy exudates in the outer plexiform layer.
Today the retinal manifestations of diabetes are classified as Early Non-proliferative Diabetic Retinopathy, Advanced Non-proliferative Diabetic Retinopathy, and Proliferative Diabetic Retinopathy.
Classification
Pathophysiology
The exact underlying pathological mechanism of diabetic microvascular disease remains poorly understood. It is believed that exposure to hyperglycemia over an extended period results in biochemical and physiologic changes that ultimately cause endothelial damage. Specific retinal capillary changes such as basement membrane thickening and selective loss of pericytes favor capillary occlusion and retinal nonperfusion.
The endothelial barrier decompensation results in serum leakage and retinal edema. The stages of disease result from continuous progression of the retinovascular damage, which leads to clinical presentations from mild to advanced proliferative lesions.
The prognosis varies among patients and depends mainly on systemic factors such as blood glucose levels, blood pressure, blood lipid profiles.[2]
Numerous hematologic and biochemical abnormalities correlate with the prevalence and severity of retinopathy:
- increased platelet adhesiveness
- increased erythrocyte aggregation
- abnormal levels of serum lipids
- defective fibrinolysis
- abnormal levels of growth hormone
- upregulation of vascular endothelial growth factor (VEGF)
- abnormalities in serum and whole-blood viscosity
- local and systemic inflammation
Differentiating Diabetic retinopathy other Diseases
Epidemiology and Demographics
Risk Factors
Screening
Natural History, Complications and Prognosis
Diagnosis
History and Symptoms
Physical Examination
Laboratory Findings
Electrocardiogram
Chest X Ray
CT
MRI
Echocardiography or Ultrasound
Other Imaging Findings
Other Diagnostic Studies
Treatment
Surgery
Medical Therapy
Primary Prevention
Secondary Prevention
Cost-Effectiveness of Therapy
Future or Investigational Therapies
Case Studies
Case #1
References
- ↑ 1.0 1.1 Template:Cite
- ↑ Antonetti, David A.; Klein, Ronald; Gardner, Thomas W. (2012-03-29). "Diabetic Retinopathy". The New England journal of medicine. New England Journal of Medicine (NEJM/MMS). 366 (13): 1227–1239. doi:10.1056/nejmra1005073. ISSN 0028-4793. PMID 22455417.