any noninflammatory disease of the retina.
central serous retinopathy a usually self-limiting condition marked by acute localized detachment of the neural retina or retinal pigment epithelium in the region of the macula, with hypermetropia.
circinate retinopathy a condition marked by a circle of white spots enclosing the macular area, leading to complete foveal blindness.
retinal manifestations of diabetes mellitus
, including microaneurysms
and punctate exudates. There are two major forms of diabetic retinopathy, nonproliferative
The nonproliferative form is characterized by dilation of the retinal veins and microaneurysms which may leak blood cells and/or plasma, causing internal hemorrhaging or edema in the retina. Edema in peripheral areas of the retina goes unnoticed by the patient and may go untreated, whereas edema occurring in the central retina (macula) causes noticeably decreased vision and is the primary cause of vision loss in nonproliferative disease. (See Atlas 4, Part D.) Treatment by local laser photocoagulation
is aimed at sealing shut the breaks in the blood vessels and preventing additional leakage of fluid into the area. Early diagnosis and treatment are essential in this disease to enhance a final visual outcome of stabilization and prevention of further loss of vision.
In proliferative diabetic retinopathy new blood vessels form near the optic disk, break through the inner membranous lining, and grow on the vitreous chamber and elsewhere in the retina and may rupture, causing gross vitreous hemorrhage. Additionally, fibrous tissue is generated secondary to the new blood vessel formation, and both the fibrous tissue and the new blood vessels become firmly attached to the posterior vitreous face. As the vitreous humor moves, the blood vessels and fibrous tissue cause tractional pulling on the retina and may result in separation or detachment of areas of retina. Panretinal laser photocoagulation is the definitive therapy. The study of early treatment for diabetic retinopathy proved the efficacy of this procedure in causing regression of the new blood vessels and prevention of vitreous hemorrhage and tractional retinal detachments, the two major causes of vision loss from this form of the disease.
exudative retinopathy a condition marked by masses of white or yellowish exudate in the posterior part of the fundus oculi, with deposits of cholestrin and blood debris from retinal hemorrhage, and leading to destruction of the macula and blindness.
hemorrhagic retinopathy retinopathy marked by profuse hemorrhaging in the retina, occurring in diabetes, occlusion of the central vein, and hypertension.
that associated with essential hypertension
; changes may include irregular narrowing of the retinal arterioles, hemorrhages in the nerve fiber layers and the outer plexiform layer, exudates and cotton-wool patches, arteriosclerotic changes, and, in malignant hypertension
. (See also Atlas 4, Part C.)
leukemic retinopathy a condition occurring in leukemia, with paleness of the fundus resulting from infiltration of the retina and choroid with leukocytes, and swelling of the disk with blurring of its margin.
retinopathy of prematurity
a disease of the developing retinal vasculature of the premature newborn. The incidence correlates with degree of prematurity; that is, the more premature the infant is, the greater the possibility of this condition occurring. The cause is vasoconstriction of retinal capillaries due to the presence of very high concentrations of oxygen in these blood vessels, which produces an overgrowth of retinal blood vessels. The vascular proliferation and exudation of blood and serum detaches the retina and produces scarring and inevitable blindness. To prevent retinopathy of prematurity it is recommended that oxygen be administered to premature newborns in as low a concentration and for as short a time as feasible. Careful monitoring of the newborn and evaluation of oxygen tension level are essential because no totally safe dosage of oxygen that will prevent the retinal changes has been found. Called also retrolental fibroplasia
proliferative retinopathy the proliferative type of diabetic retinopathy.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
retinal changes occurring in diabetes mellitus, marked by microaneurysms, exudates, and hemorrhages, sometimes by neovascularization.
In the U.S., diabetic eye disease is the leading cause of blindness in adults (ages 20-65) and is responsible for 24,000 cases of blindness each year-approximately 25% of all newly reported cases. Within 20 years after the onset of clinical disease, retinopathy occurs in nearly all patients with Type 1 diabetes mellitus (DM) and in more than 60% of patients with Type 2 DM. Retinopathy is already present at the time of diagnosis in 20% of people with Type 2 DM. The principal form is nonproliferative retinopathy, which results directly from degenerative changes in retinal capillaries. Features of this disorder, as observed on funduscopic examination, include microaneurysms; soft or cotton wool exudates, which are actually areas of microinfarction; hard or waxy exudates, which are deposits of lipid and protein from leaking capillaries; and flame or dot-and-blot hemorrhages. A few patients, principally those with Type 1 DM, develop a proliferative retinopathy characterized by neovascularization (proliferation of new capillary loops on the retinal surface). The changes of diabetic retinopathy are most clearly visualized by fluorescein angiography. Either type of retinopathy can impair vision by destroying retinal tissue directly and by predisposing to retinal edema, retinal detachment, and vitreous hemorrhage, but proliferative retinopathy is more rapidly progressive and more likely to lead to blindness without treatment. Controlled clinical studies have shown that maintaining blood glucose levels as near normal as possible at all times in people with DM substantially retards the onset and rate of progression of retinopathy. Laser photocoagulation is effective in arresting neovascularization in proliferative diabetic retinopathy and macular edema. Surgery may be required for treatment of vitreous hemorrhage or retinal tears.
Farlex Partner Medical Dictionary © Farlex 2012