Clinical use and research applications of Heidelberg retinal angiography and spectral‐domain optical coherence tomography – a review

Abstract

Fluorescein angiography (FA) was discovered by Nowotny and Alvis in the 1960s of the 20th century and has evolved to become the 'Gold standard' for macular diagnostics. Scanning laser imaging technology achieved enhancement of contrast and resolution. The combined Heidelberg retina angiograph (HRA2) adds novel innovative features to established fundus cameras. The principle of confocal scanning laser imaging provides a high resolution of retinal and choroidal vasculature with low light exposure providing comfort and safety for the patient. Enhanced contrast, details and image sharpness image are generated using confocality. For the visualization of the choroid an indocyanine green angiography (ICGA) is the most suitable application. The main indications for ICGA are age-related macular degeneration, choroidal polypoidal vasculopathy and choroidal haemangiomas. Simultaneous digital FA and ICGA images with threedimensional resolution offer improved diagnosis of retinal and choroidal pathologies. High-speed ICGA dynamic imaging can identify feeder vessels and retinal choroidal anastomoses, ensuring safer treatment of choroidal neovascularization. Autofluorescence imaging and fundus reflectance imaging with blue and infrared light offer new follow-up parameters for retinal diseases. Finally, the real-time optical coherence tomography provides a new level of accuracy for assessment of the angiographic and morphological correlation. The combination of various macular diagnostic tools, such as infrared, blue reflectance, fundus autofluorescence, FA, ICGA and also spectral domain optical coherence tomography, lead to a better understanding and improved knowledge of macular diseases.

Measurement and clinical implications of choroidal thickness in patients with inflammatory bowel disease

“…Spectral domain optical coherence tomography (SD-OCT) is a noninvasive method for studying retinal layer structures in a range of retinal conditions (7) . Recently, a new method of SD-OCT, termed enhanced depth imaging (EDI), has been shown to be capable of visualizing the full thickness of the choroid (8) .…”

Drusen Characteristics Revealed by Spectral-Domain Optical Coherence Tomography and Their Corresponding Fundus Autofluorescence Appearance in Dry Age-Related Macular Degeneration

“…At critical concentrations, the lipofuscin toxicity becomes manifest, interfering with normal cell function and leading to cell death. Changes in the normal FAF appearance may be among the first signs of retinal disease before they are evident funduscopically [4] . Alterations on FAF images have been reported to correlate with reduced photoreceptor function and retinal sensitivity [15][16][17][18] .…”

“…Many investigators have used both confocal scanning laser ophthalmoscopy devices and fundus camera-based systems for describing in vivo fundus autofluorescence (FAF) changes in early AMD [3][4][5][6][7][8][9][10][11][12][13][14] . The premise of FAF assessment relies on native fluorescence emanating from physiological retinal components, providing an indication of healthy function of the retinal pigment epithelium (RPE) monolayer.…”

Imaging in DRY AMD

“…2b) and near infrared auto-fluorescence (NIA) (Fig. 2c) which are particularly useful for the detection of geographic atrophy [20]. The limitations of the cSLO depend mostly on ocular media opacities and pupil diameter.…”