Early AMD

Core Messages

›Early AMD is characterized by drusen and/or irregular focal hyperand hypopigmentations at the posterior pole of the eye.

›There is a high degree of interindividual variability in clinical manifestations of early AMD.

›Various types of drusen can be distinguished on the basis of ophthalmoscopy, fluorescein angiography, optical coherence tomography, confocal scanning laser ophthalmoscopy and histology.

›Early stages of AMD are usually associated with good visual function, but tend to change dynamically over time and have a prognostic impact on the progression to late-stage AMD with severe visual loss.

M. Dietzel (*) • D. Pauleikhoff

Department of Ophthalmology, St. Franziskus Hospital, Münster, Germany

e-mail: martha.dietzel@gmx.de; dapauleikhoff@muenster.de

F.G. Holz

Department of Ophthalmology, University of Bonn, Bonn, Germany

e-mail: frank.holz@ukb.uni-bonn.de

A.C. Bird

Department of Ophthalmology, Moorfields Eye Hospital, London, UK

e-mail: alan.bird@ucl.ac.uk

6.1 Introduction

Age-related macular degeneration (AMD) involves a variety of phenotypic changes at the posterior pole. These phenotypic findings change dynamically over time, which is not always evident from a single funduscopy. Earlystage disease is characterized by drusen and/or irregular focal hypoor hyperpigmentations. Late-stage phenotypes encompass choroidal neovascularization (CNV), detachments of the retinal pigment epithelium (RPE), tears in the RPE, and geographic atrophy.

Individual clinical variability and phenotypes for each form may reflect heterogeneous etiological factors at both molecular and cellular levels. In recent years, genetic polymorphisms that are associated with an increased risk of developing AMD have been discovered. Specifically, these polymorphisms involve components of the complement system (inter alia complement factor H) as well as theage-relatedmaculopathysusceptibilitygene2(ARMS2 gene). The ARMS2 gene product is hypothesized to be a mitochondrial protein that may play a role in responding to oxidative stress in retinal tissue [1].

The clinical terms of “dry” and “wet” AMD divide manifestations into two broad categories and can be more precisely characterized for each patient (Table 6.1). Both drusen (early stage) and geographic atrophy (late stage) are non-exudative, i.e., “dry” forms of the disease. Drusen are typically associated with relatively good visual acuity and only minor visual symptoms. For the majority of the affected patients, the condition will not progress to late-stage AMD with severe visual loss. These early manifestations of AMD are very frequent. For late-stage disease, the exudative form resulting from choroidal neovascularization is the most common cause of severe visual decline, whereas about