AGE RELATED MACULAR DEGENRATIVE DISEASE

Age Related Macular degenrative disease

Age Related Macular degenrative disease

Introduction

Age-related macular degeneration (AMD) is a disease associated with aging that gradually destroys sharp, central vision. Central vision is needed for seeing objects clearly and for common daily tasks such as reading and driving. Age-related macular degeneration (AMD), already the leading cause of irreversible blindness among the elderly in industrialized nations, promises to exact an even greater toll with the imminent demographic right-shift means the human populations and population segments, especially in increasingly aging populations. While our understanding of molecular events presaging AMD has grown in the last decade, its pathogenesis remains puzzling, and consequently our therapeutic arsenal remains limited. Nevertheless, the burgeoning development of directed molecular interventions (monoclonal antibodies, aptamers, ribozymes, gene transfer therapy) combined with the development of targeted delivery modalities offers hope in the battle against this blinding affliction.

Defination

Diagnosis

Diagnosis of neovascular AMD when it might be treatable is based mainly on an ophthalmoscopic examination using slit-lamp biomicroscopy and fluorescein angiography. Ophthalmoscopy is used to detect macular abnormalities that have characteristic features of neovascular AMD, including an elevation of the retinal pigment epithelium, subretinal or intraretinal fluid, lipid or hemorrhage, subretinal green-gray lesions, or subretinal fibrous tissue. Fluorescein angiography is a special form of photographic imaging (not using x-rays) by which choroidal neovascularization can be visualized. Fluorescein dye is injected intravenously, and fundus photographs are taken at intervals up to 10 minutes after the dye injection. If choroidal neovascularization is suspected, imaging with fluorescein angiography can confirm its presence and determine whether treatment is indicated. The composition, size, and location of choroidal neovascularization on fluorescein angiography can influence the subsequent management and prognosis.

Patterns of fluorescence in these images can categorize choroidal neovascularization as classic or occult. Classic choroidal neovascularization appears as a bright area of well-demarcated choroidal fluorescence on the early phase of the angiogram, with leakage of fluorescein beyond the boundaries of this bright area appearing in the mid-phase frame (1 to 2 minutes after dye injection) and late-phase frame (5 to 10 minutes after dye injection). Occult choroidal neovascularization is indicated by an area of stippled or granular hyperfluorescence in the late-phase frames of the angiogram.

There are large variations in the natural course of AMD with respect to occult and classic choroidal neovascularization, depending on the composition of the neovascular lesion. In addition, the size and location of the lesion in relation to the central macula can strongly influence the course of the condition. Whereas most choroidal neovascular lesions in AMD include occult neovascularization and are subfoveal (under the center of the fovea), loss of visual acuity is most rapid in patients who have either classic choroidal neovascularization without occult neovascularization or predominantly classic choroidal neovascularization (the area of neovascularization is = 50% of the area of the entire lesion). The average loss of visual acuity is slower in patients who have occult choroidal neovascularization without classic neovascularization or who have minimal classic choroidal neovascularization (the area of neovascularization is <50% but >0% of ...