Abstract
Purpose :
To qualitatively evaluate the organization of outer retinal bands in normal and diseased humans using a novel ultrahigh resolution VISOCT system.
Methods :
Adult subjects with retinal disease and controls were recruited for imaging with a custom-built VISOCT (1.3μm axial resolution, 500~650nm, line rate acquisition 100kHz, power at pupil plane ~0.24mW). Subjects with significant media opacity, poor signal quality, or inability to fixate were excluded. A 4-line radial high-definition scanning pattern (A-lines [2048*32]*B-scan [4]) was used with 32 modulated A-lines over ~0.1 mm orthogonal to the B-scan to produce images with reduced speckle noise. Linear-in-k spectrometer offers 7.2dB roll-off and shot-noise limited performance was achieved by active noise cancellation. Each B-scan covered ~6.6mm and acquired in 2.6 seconds.
Results :
15 eyes of 10 subjects (3 controls, 3 non-neovascular age related macular degeneration (NNAMD), 1 macular telangiectasia type 2 (MacTel), 2 hydroxychloroquine (HCN) toxicity and 1 acute macular neuroretinopathy (AMN); mean age 56±21) were recruited. Figure 1 illustrates a control retina with 6 hypereflective outer retinal bands (B1-6): external limiting membrane (ELM,B1), ellipsoid zone (EZ,B2) and putative rod and cone photoreceptor outer segment tips (POS, B3-B4), retinal pigment epithelium (RPE,B5) and Bruch’s Membrane (BM,B6). Control retina demonstrated only 5 bands in the central fovea and 6 bands in parafoveal region. Subjects with retinal disease demonstrated specific alterations in bands B1-6. Specifically, subjects with NNAMD consistently demonstrated abnormal thickening of the B5-B6 space consistent with BLam deposits in addition to variable loss of definition in B1-5 (Figure 2). Subjects with known or suspected HCN toxicity demonstrated attenuation of B2-5 but no thickening of B5-B6. Subjects with AMN and MacTel demonstrated attenuation of B2-B3 and B1-B5, respectively, but no thickening of the B5-6.
Conclusions :
Ultrahigh resolution VISOCT imaging demonstrates novel banding patterns and attenuation of outer retinal features in heathy and diseased eyes. Specific patterns of outer retinal pathology provide novel pathophysiologic insight into these diseases.
This abstract was presented at the 2023 ARVO Imaging in the Eye Conference, held in New Orleans, LA, April 21-22, 2023.