Table 1 Comparison between retinal imaging technologies
From: Modern technologies for retinal scanning and imaging: an introduction for the biomedical engineer
Technology | Field of View (FOV) in angular degrees | Resolution in μm | Detectable features of interest |
|---|---|---|---|
Fundus photography | 20°…30°…50° (60°) (up to 110° with Montage Software) | ca. 10 μm (lateral); Depends on the FOV | Optic disc, macula, posterior pole, retinal blood vessels, drusen, pigmentation, fluorescein angiography |
Hyperspectral Imaging (HIS) | 7…20° | Similar to fundus photography | Retinal blood vessels, (oxygen saturation), macular pigment, optic disc drusen |
Confocal Scanning Laser Ophthalmoscope (cSLO) | 5…25° | 5-10 μm lateral 20–50 μm axial (distance between slices) | Drusen, microvascular angiopathy, nerve fiber bundles, angioscotomas |
Adaptive Optics Scanning Laser Ophthalmoscope (AOSLO) | 1°…8° | 1.5…3 μm lateral less than cone-to-cone spacing; depends on motion stabilization | Individual cone photoreceptors (diameter 5–7 μm) |
Scanning Laser Polarimeter (SLP) | 40° x 20° | 46 μm lateral | Retinal nerve fiber layer thickness around the optic disc |
Optical Coherence Tomography (OCT) | 5°…15° | 3…10 μm lateral (depends on the the numerical aperture) 2…10 μm axial (depends on the bandwidth of the source and the axial scan speed) | Microscopic structures in intra-retinal layers, choroidal vessel system, |
Polarisation Sensitive Optical Coherence Tomography (PS OCT) | 20°…40° | 5…20 μm lateral (depends on the the numerical aperture) 10–12 μm axial (depends on the bandwidth of the source and the axial scan speed) | Tissue organization at the molecular level, retinal pigment epitelium (polarization scrambling), drusen, Bruch’s membrane, retinal ganglion cells |
Retinal Birefringence Scanning (RBS) | 3°… 20° | Depends on the sampling rate | Fovea, optic nerve |