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Imaging Optical Coherence Tomography Imaging and Quantitative Assessment for Monitoring Dry Age-related Macular Degeneration Albert J Augustin Head, Department of Ophthalmology, Staedtisches Klinikum Karlsruhe, Germany Abstract The purpose of this article is to show the feasibility of the ‘Advanced [retinal pigment epithelium] RPE analysis’ software tool to measure drusen area and volume as well as the area of geographic atrophy (GA) in patients with dry age-related macular degeneration (AMD). The source data from spectral domain optical coherence tomography (SD-OCT) images obtained from three patients with confirmed dry AMD using Cirrus™ HD-OCT (Carl Zeiss Meditec) were re-evaluated with the new software analysis tool Advanced RPE analysis. The area of GA as well as drusen area and volume were measured and analysis of results were presented along with calculated values in two clearly arranged screens. Changes between visits were easily detectable and could be followed over time. Results correlated well with clinical observation. The conclusion reached was that the new Advanced RPE analysis software allows the automated, objective and quantitative assessment of atrophic lesions and drusen. It thus could prove to be useful in determining disease stages as well as prognosis more precisely, and provides the opportunity to monitor the effectiveness of new therapies in clinical trials. Keywords Spectral domain optical coherence tomography (SD-OCT), imaging, drusen, geographic atrophy, age-related macular degeneration (AMD), dry AMD, Advanced retinal pigment epithelium (RPE) analysis tool Disclosure: The author has no conflicts of interest to declare. Received: 15 February 2012 Accepted: 20 March 2012 Citation: European Ophthalmic Review, 2012;6(2):72–7 Correspondence: Albert J Augustin, Staedtisches Klinikum Karlsruhe, Augenklinik, Moltkestrasse 90, 76133 Karlsruhe, Germany. E: Support: The publication of this article was funded by Carl Zeiss Meditec. Age-related macular degeneration (AMD) is the leading cause of blindness among elderly individuals in developed industrialised countries and affects approximately 30–50 million people worldwide. 1–4 There are two forms of AMD: dry AMD (dAMD) which accounts for about 80 % of all cases of AMD, and neovascular AMD (nAMD). Early stage AMD is characterised by soft drusen (protein and lipid deposits between retinal pigment epithelium [RPE] and Bruch’s membrane) and pigment abnormalities (hyper- or hypopigmentation). Visual acuity is usually not deteriorated in early stages of AMD. However, they can progress to late stages of AMD: geographic atrophy (GA; late stage of dAMD) or neovascular AMD. Vision loss due to AMD is mainly attributable to these advanced forms. It is estimated that due to demographic changes, in 2020 the vision-threatening advanced forms will increase by more than 50 %. 5 Thus, a better understanding of the pathogenesis may lead to the development of new powerful therapies and is a matter of public and economic concern. While there are several therapeutic approaches for nAMD, so far there are no established guidelines for dry AMD treatment. Although vitamin supplementation can slow the progression of dAMD in advanced forms, uncritical administration is not advisable due to possible adverse reactions. 6,7 New drugs and advanced concepts for the treatment of dry AMD are waiting for further investigation. 8–11 However, their evaluation of efficacy against dry AMD turns out to be difficult and time consuming. In contrast to nAMD, patients with dry AMD can maintain good central visual 72 acuity until the disease progresses into the foveal centre. Thus, visual acuity might not be an appropriate clinical end-point in early stage clinical trials to determine drug efficacy against dry AMD. Therefore, new reliable clinical trial end-points enabling efficacy evaluation in the shortest period of time are needed. Furthermore, diagnostic methods should be established which allow for reliable, objective, automated and quantitative assessment of disease progression in large patient populations. As eyes with soft indistinct drusen or retinal pigmentary abnormalities at baseline are more likely to develop late AMD as compared to eyes without these lesions, 12 two encouraging options to monitor progression of dry AMD are the volumetric assessment of drusen as well as localisation and quantitative assessment of atrophic lesions in GA. The gold standard for assessing drusen number and size as well as pigmentary changes are stereoscopic colour fundus photographs analysed by qualified reading centres. 13,14 Fundus autofluorescence (FAF) has also been used for imaging of atrophic lesions in GA to indicate GA progression. 15–17 However, accuracy delineating GA by fundus photography has been reported to be moderate, 14,18–20 and both approaches allow for two-dimensional assessment of the macula only, so volumetric measurement of drusen and quantitative measurement of disease progression is impossible. Quantitative assessment of drusen, however, might become an important parameter in clinical trials to evaluate efficacy of new drugs against AMD. 21,22 © TOUCH BRIEFINGS 2012