Objective: To visualize and characterize morphological changes in the retina associated with aging and age-related macular degeneration (AMD) using high-resolution imaging techniques.
Methods: Twenty-five subjects previously diagnosed with AMD or a propensity to develop AMD were recruited for our study. Each patient received a complete examination accompanied by clinical imaging with the Spectralis HRA+OCT and white light fundus photography. Adaptive optics confocal scanning laser ophthalmoscopy (AO-cSLO) was then used to investigate retinal perturbations associated with sub-RPE deposits and geographic atrophy (GA) which were identified by an experienced ophthalmologist.
Results: We acquired multi-modal images suitable for image analysis in 80% (20/25) of the subjects in the study. The mean patient age was 78 (± 9.8 years) with multiple patients representing each of the AREDS classification levels of AMD. The ability to obtain quality images was largely unrelated to either age or AMD stage. Visible defects observed in the outer retina using SD-OCT were shown to correspond with dark regions of the photoreceptor mosaic in intermediate AMD patients imaged with AO-cSLO. Conversely, patients with GA exhibited bright, hyper-reflective regions in AO-cSLO images corresponding to RPE atrophy seen on SD-OCT.
Conclusions: Early identification of morphological biomarkers using highly sensitive imaging techniques has the potential to detect retinal pathology prior to visual dysfunction. Visualizing subtle changes in retinal structure and spatial distribution of photoreceptors may also provide insight into the progressive nature of AMD suggesting that image-based biomarkers can be used to identify new therapeutic targets to preserve central visual acuity.