Optical coherence tomography (OCT) generates cross-sectional retinal imaging with micrometer-level axial resolution
1 and has become a critical tool in the evaluation and treatment of a variety of retinal diseases. Commercially available high speed spectral-domain OCT (SD-OCT) uses an 870-nm wavelength light source that provides excellent imaging of the vitreoretinal interface and retina,
2 but often lacks full-thickness visibility of the choroid due to depth and density of choroidal tissue and light attenuation by the retinal pigment epithelium (RPE).
3 Enhanced depth imaging (EDI), first described by Spaide et al.,
4 is a technique that can be employed on the SD-OCT machine to provide deeper imaging beneath the RPE and into the choroid. Using EDI-OCT, Spaide and others have shown that the choroid undergoes both age-related changes as well as pathologic changes in various retinal disease processes that were not easily visible prior to use of OCT.
5–7 Due to increased interest in choroidal imaging with OCT, other methods have been used to try to better visualize and measure the choroid, including use of swept-source OCT (ss-OCT)
8 and longer wavelength OCT.
9–11 All of these methods, however, potentially cause loss of clear visualization of the retinal surface, where other pathology such as vitreomacular traction or epiretinal membrane might be present and contributing to poor vision. To date, no studies have compared image quality of the vitreoretinal interface, sensory retina, and choroid to the readily available EDI-OCT technique demonstrated by Spaide et al.
4
The purpose of this study was to compare commercially-available Heidelberg Spectralis (Heidelberg Engineering, Heidelberg, Germany) 870-nm SD-OCT imaging of the vitreous, retina, and choroid with a prototype longer wavelength 1050-nm Heidelberg Spectralis SD-OCT imaging, with and without EDI. Specifically, the aims were to determine whether 1050-nm SD-OCT imaging provided improved choroidal visualization when compared with standard 870-nm imaging (with and without EDI) across a spectrum of patients with and without macular disease, and whether that additional benefit was at the expense of visualization of the retina and vitreous.