Simultaneous confocal scanning laser ophthalmoscopy combined with high-resolution spectral-domain optical coherence tomography: a review

Abstract

We aimed to evaluate technical aspects and the clinical relevance of a simultaneous confocal scanning laser ophthalmoscope and a high-speed, high-resolution, spectral-domain optical coherence tomography (SDOCT) device for retinal imaging. The principle of confocal scanning laser imaging provides a high resolution of retinal and choroidal vasculature with low light exposure. Enhanced contrast, details, and image sharpness are generated using confocality. The real-time SDOCT provides a new level of accuracy for assessment of the angiographic and morphological correlation. The combined system allows for simultaneous recordings of topographic and tomographic images with accurate correlation between them. Also it can provide simultaneous multimodal imaging of retinal pathologies, such as fluorescein and indocyanine green angiographies, infrared and blue reflectance (red-free) images, fundus autofluorescence images, and OCT scans (Spectralis HRA + OCT; Heidelberg Engineering, Heidelberg, Germany). The combination of various macular diagnostic tools can lead to a better understanding and improved knowledge of macular diseases.

Figure 1

Example of a normal eye imaged with the Spectralis SDOCT. The infrared reflectance cSLO image (lower left) shows a normal fundus which corresponds to the normal SDOCT B-scan. The green lines represent the location, and the green arrow shows the exact orientation of the B-scan. All the retinal layers are indicated on the SDOCT scan (ILM: internal limiting membrane; NFL: nerve fiber layer; GCL: ganglion cell layer; IPL: inner plexiform layer; INL: inner nuclear layer; OPL: outer plexiform layer; ONL: outer nuclear layer; ELM: external limiting membrane; IS/OS: photoreceptor inner/outer segment junction; RPE: retinal pigment epithelium).

Figure 2

A 71-year-old man with a pigment epithelial detachment in the presence of neovascular AMD in the right eye. In the SDOCT scan the pigment epithelial detachment is readily visualized underneath the fovea associated with intraretinal cysts and subretinal fluid. It is also possible to identify the subretinal neovascular membrane and the vitreoretinal interface.