A Collaborative Resource of Heidelberg Multimodal Imaging of Intermediate and Early Atrophic AMD Cases to Study Prediction of Disease Progression

Age-related macular degeneration (AMD) is the commonest cause of visual impairment in older people in Europe. It is a slowly progressing complex disorder. The clinical progression is best described as early, intermediate, and advanced based on the latest classification system on colour fundus photographs. However, multimodal imaging has enabled visualisation of further changes in the retina on optical coherence tomography (OCT), infrared imaging, and autofluorescence. So, a large database of imaging data of intermediate AMD will facilitate researchers to study the disease progression in detail. This study is a collaborative effort by investigators across many Member Sites in Europe that are members of EVICR.net to pool datasets for secondary analysis.

EVICR.net is a network of Ophthalmological Clinical Research Sites, dedicated to performing multinational clinical research in ophthalmology with the highest standards of quality, following the European and International Directives for Clinical Research in order to strengthen the capacity of the European Union to study the determinants of ophthalmic diseases and to develop and optimise the use of diagnostic, prevention and treatment strategies in ophthalmology.

EVICR.net Eye Platform is a long-term initiative to establish a platform to gather high quality ophthalmology data generated in Europe and allow the secondary use of data in performing large data analysis and foster clinical research.

With this Eye Platform EVICR.net aims to provide technological solutions that allow overcoming privacy and regulation issues associated with the sharing of data from different institutions/countries, in a secure, easy to use manner.

With EVICR.net Eye Platform, the Members Sites will have the opportunity to participate in clinical research with secondary use data analysis; Authorship of publications and presentations of Results; the opportunity to propose new analysis to answer key research questions; and increase overall visibility and stature as researchers

Background:

On colour fundus photographs, drusen size and changes in retinal pigment epithelium are used to classify the severity of AMD into early, intermediate and advanced stages.Early AMD is characterised by medium sized drusen of 63 µm to 124 µm with no RPE changes. Intermediate AMD include large drusen (≥125 µm) or medium-sized drusen with pigmentary changes. These eyes with intermediate AMD have a high risk of progression to advanced AMD, including either geographic atrophy or exudative AMD due to macular neovascularisation (MNV). Visual deterioration is seen in these two advanced stages. Therefore, there is an unmet need to identify those at risk of disease progression to advanced AMD so that preventive options can be evaluated and implemented. However, a significant amount of research is required to better understand the risk of disease progression.

With the advent of multimodal imaging, there is growing evidence of new imaging markers of disease progression in eyes with intermediate AMD. For example, on infrared reflectance (IR), optical coherence tomography (OCT) and autofluorescence (AF), subretinal drusenoid deposits (SDD) are seen in some eyes with intermediate AMD and these have been identified as a predictor of fast progression to advanced AMD. Multimodal images have also shown that early atrophic changes may occur in intermediate AMD before the classical diagnosis of atrophy seen as hypoautofluorescence on AF. The Classification of Atrophy Meetings (CAM) group defined a few imaging characteristics as precursors of geographic atrophy and designated them together as incomplete retinal pigment epithelium and outer retinal atrophy (iRORA). A region of signal hypertransmission into the choroid of <250um, a corresponding zone of attenuation or disruption of the RPE, with or without the persistence of basal laminar deposits (BLamD) and evidence of overlying photoreceptor degeneration, i.e., subsidence of the inner nuclear layer (INL) and outer plexiform (OPL), presence of a hyporeflective wedge in the Henle fiber layer (HFL), thinning of the outer nuclear layer (ONL), disruption of the external limiting membrane (ELM), or disintegrity of the ellipsoid zone (EZ), and when these criteria do not meet the definition of complete retinal pigment epithelium and outer retinal atrophy (cRORA) that defines geographic atrophy on colour photographs. cRORA is defined as zone of hyper transmission of ≥250 µm, zone of attenuation or disruption of RPE band of ≥250 µm with evidence of overlying photoreceptor degeneration characterised by features that include outer nuclear layer (ONL) thinning, external limiting membrane (ELM) loss, and ellipsoid zone (EZ) or interdigitating zone (IZ) loss. Multimodal imaging also showed that drusen sizes on OCT are indeed larger than visualised on colour photographs. On en-face OCT, large drusen is defined as drusen diameter ≥145 µm, medium drusen diameters 100 µm to 144 µm, and small drusen diameters <100 µm. So, these markers and other novel imaging characteristics may better predict disease progression from intermediate AMD.However, a large multimodal image resource is required to develop such prediction models.

The Heidelberg Spectralis device enables multimodal imaging, and the OCT scans can be segmented by in-built automated Heidelberg software and manually corrected where necessary. So, a large database of Heidelberg imaging data of intermediate AMD will facilitate researchers to study the disease progression in detail.