Purpose:
To evaluate the utility of a combined adaptive optics - optical coherence tomography / adaptive optics - scanning laser ophthalmoscope (AO-OCT/AO-SLO) system for retinal imaging of patients with geographic atrophy.
Methods:
An ultra-high-resolution system allowing simultaneous acquisition of retinal images from both AO-OCT and AO-SLO was used to image retinae of patients with central and non-central geographic atrophy that were also tested with microperimetry and mfERG. Image acquisition was based on two different wavelengths, 840 nm (135 nm bandwidth) for OCT, and 680 nm (10 nm bandwidth) for SLO. Additionally, the OCT light source served as the beacon for wavefront sensing in the AO sub-system. Monochromatic aberration correction was based on a Shack-Hartmann wavefront sensor and a 97-element membrane magnetic deformable mirror. A custom achromatizing lens corrected longitudinal chromatic aberration in the OCT beam. Custom visualization software displayed retinal images acquired with both modalities and registered them to clinical OCT, fundus autofluorescence and color fundus photography.
Results:
Our combined AO-OCT/AO-SLO system showed significant changes in microscopic structures of outer retinal layers at the retinal locations corresponding to the edge of the geographic atrophy. As an example, a montage of 3 AO-OCT B-scans acquired around the atrophic area of a 68-year-old patient is shown and co-registered with clinical OCT and fundus autofluorescence and color fundus photography.
Conclusions:
Imaging of geographic atrophy with a combined ultrahigh resolution AO-OCT/AO-SLO system allows visualization of microscopic morphological features not easily visualized with current clinical systems. Importantly, AO-OCT provides clear visualization of microscopic volumetric features at the edge of the atrophy that may be targeted for study of the disease progression and efficacy of novel therapies.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • age-related macular degeneration • image processing