Similar effects are aspired by techniques like image averaging and/or enhanced depth imaging (Fig. The longer wavelengths is thought to enhance visualization of subretinal tissue and choroidal structures (Fig. Ĭommercial SS-OCT devices employ a longer wavelength (>1050 nm) laser light source and have scan rates as fast as 200,000 Hz. The cSLO features simultaneous eye-tracking based on a retinal fundus reflectivity image, enabling accurate and repeatable alignment of OCT images, advanced noise reduction and an auto rescan function for precise placement of follow-up scans. The Spectralis ® device by Heidelberg Engineering (Heidelberg, Germany) was the first commercially available SD-OCT device that combines the OCT technique with a confocal scanning laser ophthalmoscope (cSLO) using a near-infrared laser light source (815 nm, Fig. įor SD-OCT devices, technical improvements has enabled scan rates up to 250,000 Hz in commercially available devices. Subsequently, the spectral domain (SD) and swept source (SS) imaging technologies have dramatically improved sampling speed and signal-to-noise ratio by using a high-speed spectrometer that measures light interferences from all time delays simultaneously or a tunable frequency swept laser light source (that sequentially emits various frequencies in time) and photodetectors instead of a spectrometer to measure the interference, respectively. Nevertheless, it became widely accepted for the assessment of various retinal diseases. The first commercially available OCT devices were based on time-domain detection that featured rather low scan rates of 400 A-scans per second leading to possible errors associated with eye motion and reduced measurement accuracy as well as reproducibility (Fig. ( a) The time-domain OCT (Stratus OCT, Carl Zeiss Meditec, Jena, Germany) enables the investigator to get a (more.) The different generations of OCT imaging devices in exemplary healthy subjects is demonstrated. Evolution of OCT imaging in retinal diagnostics.

Retina scan high resolution