Abstract

SA.23.03

Imaging geographic atrophy progression by high resolution spectral domain OCT in patients with age-related macular degeneration

Monika Fleckenstein, Steffen Schmitz-Valckenberg, Irene Krämer, Robert P. Finger, Hans-Martin Helb, Peter Charbel Issa, Carsten H. Meyer, Frank G. Holz
Universitäts-Augenklinik Bonn

Purpose
To investigate ultra-structural alterations in a prospective longitudinal study in eyes with geographic atrophy (GA) due to age-related macular degeneration (AMD) by spectral domain (SD) optical coherence tomography (OCT).
Methods
Twenty-eight eyes of 15 patients (mean age 77.9 ± 5.5 years) with GA had serial examination with a mean follow-up period so far of 0.81 ± 0.27 years by simultaneous confocal scanning laser ophthalmoscopy and SD-OCT imaging (Spectralis® HRA+OCT, Heidelberg Engineering, Germany). Real-time registration of eye movements allowed for alignment of follow-up to baseline scans and therefore subsequent accurate three-dimensional analysis of structural alterations over time. Longitudinal SD-OCT images were analysed including evaluation of qualitative alterations and measurements of total retinal thickness (RT) at the GA junction at baseline and at the same location in follow-up scans.
Results
Atrophic areas showed enlargement in the cSLO image while examination period. SD-OCT showed that GA enlargement or evolution was associated with advancing loss of the retinal pigment epithelium (RPE)- and inner-segment/outer-segment (IS/OS)-layers with subsequent disappearance of the external limiting membrane. The outer nuclear layer progressively collapsed within the atrophic lesion. Areas preceding atrophy displayed an irregular RPE- and IS/OS-layer, frequently associated with sub-RPE deposits. In the perilesional zone, migration of hyperreflective material and changes in RPE thickness were noted, and both increase in drusen volume as well as drusen fading occurred at different regions. At baseline, median RT at the GA junction was 273 µm (interquartile range, IQR 242-296 µm). Progression of GA resulted in a median reduction of RT of 16 µm (IQR 7.75-28.25 µm).
Conclusions
Recent developments in retinal imaging technologies allow for high resolution imaging of dynamic morphological alterations in retinal diseases. In eyes with GA, marked changes within the atrophic lesion, at the junctional and the perilesional zone were identified over a relatively short time period. Completion of the study will provide further understanding of the natural history of GA progression. This information may also be useful in monitoring future therapeutical interventions aiming at slowing GA enlargement.

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