Showing papers on "Optical coherence tomography published in 2005"
TL;DR: An intravitreal injection of bevacizumab may provide an effective, safe, and inexpensive option for patients with age-related macular degeneration who are losing vision secondary to macular neovascularization.
Abstract: To determine whether intravitreal bevacizumab could improve optical coherence tomography and visual acuity outcomes in a patient with neovascular age-related macular degeneration who was responding poorly to pegaptanib therapy, an intravitreal injection of bevacizumab (1.0 mg) was given. Within 1 week, optical coherence tomography revealed resolution of the subretinal fluid, resulting in a normal-appearing macular contour. The improved macular appearance was maintained for at least 4 weeks, and visual acuity remained stable. No inflammation was observed. An intravitreal injection of bevacizumab may provide an effective, safe, and inexpensive option for patients with age-related macular degeneration who are losing vision secondary to macular neovascularization.
938 citations
TL;DR: Three-dimensional OCT imaging can be performed using high-speed ultrahigh-resolution OCT and may help to elucidate the structural changes associated with retinal disease as well as improve early diagnosis and monitoring of disease progression and response to treatment.
751 citations
TL;DR: A number of different OCT techniques are discussed in some detail including time-domain, frequency- domain, full-field, quantum and Doppler OCT.
Abstract: In this paper, we review the developments in optical coherence tomography (OCT) for three-dimensional non-invasive imaging. A number of different OCT techniques are discussed in some detail including time-domain, frequency-domain, full-field, quantum and Doppler OCT. A theoretical treatment is given and some relevant comparisons made between various implementations. The current and potential applications of OCT are discussed, with close attention paid to biomedical imaging and its metrological issues.
655 citations
TL;DR: The newly developed macular segmentation algorithm described herein demonstrated its ability to quantify objectively the glaucomatous damage to RGCs and NFL and to discriminate between glaucatous and normal eyes.
Abstract: Purpose
To develop a software algorithm to perform automated segmentation of retinal layer structures on linear macular optical coherence tomography (StratusOCT; Carl Zeiss Meditec, Inc., Dublin, CA) scan images and to test its performance in discriminating normal from glaucomatous eyes in comparison with conventional circumpapillary nerve fiber layer (cpNFL) thickness measurement.
612 citations
TL;DR: The ability of the system to image pulsatile flow in the dermis and to perform functional imaging of large volumes demonstrates the clinical potential of multifunctional spectral-domain OCT.
Abstract: We demonstrate a high-speed multi-functional spectral-domain optical coherence tomography system, using a broadband light source centered at 1.3 µm and two InGaAs line scan cameras capable of acquiring individual axial scans in 24.4 µs, at a rate of 18,500 axial scans per second. Fundamental limitations on the accuracy of phase determination as functions of signal-to-noise ratio and lateral scan speed are presented and their relative contributions are compared. The consequences of phase accuracy are discussed for both Doppler and polarization-sensitive OCT measurements. A birefringence artifact and a calibration procedure to remove this artifact are explained. Images of a chicken breast tissue sample acquired with the system were compared to those taken with a time-domain OCT system for birefringence measurement verification. The ability of the system to image pulsatile flow in the dermis and to perform functional imaging of large volumes demonstrates the clinical potential of multi-functional spectral-domain OCT.
502 citations
TL;DR: It is demonstrated that by correcting for spurious timing-induced phase errors, excellent flow sensitivity can be achieved, limited only by the imaging signal-to-noise ratio.
Abstract: Phase-resolved Doppler optical coherence tomography has been used to image blood flow dynamics in various tissues using both time-domain and spectral-domain optical coherence tomography techniques. In this manuscript, we present phase-resolved Doppler imaging with a high-speed optical frequency domain imaging system. We demonstrate that by correcting for spurious timing-induced phase errors, excellent flow sensitivity can be achieved, limited only by the imaging signal-to-noise ratio. Conventional and Doppler images showing flow in an Intralipid phantom and in human skin are presented. Additionally, we demonstrate the ability of phase-resolved OFDI to measure high flow rates without the deleterious effects of fringe washout.
453 citations
TL;DR: A closed-loop adaptive optics system using a Hartmann-Shack wavefront sensor and a bimorph deformable mirror is combined with Fourier-domain optical coherence tomography to image microscopic blood vessels and the cone photoreceptor mosaic.
Abstract: We have combined Fourier-domain optical coherence tomography (FD-OCT) with a closed-loop adaptive optics (AO) system using a Hartmann-Shack wavefront sensor and a bimorph deformable mirror. The adaptive optics system measures and corrects the wavefront aberration of the human eye for improved lateral resolution (~4 μm) of retinal images, while maintaining the high axial resolution (~6 μm) of stand alone OCT. The AO-OCT instrument enables the three-dimensional (3D) visualization of different retinal structures in vivo with high 3D resolution (4×4×6 μm). Using this system, we have demonstrated the ability to image microscopic blood vessels and the cone photoreceptor mosaic.
450 citations
TL;DR: Reflection-mode photoacoustic microscopy with dark-field laser pulse illumination and high-numerical-aperture ultrasonic detection is designed and implemented in noninvasively imaged blood vessels in the skin in vivo, capable of imaging optical-absorption contrast as deep as 3 mm in biological tissue.
Abstract: Reflection-mode photoacoustic microscopy with dark-field laser pulse illumination and high-numerical-aperture ultrasonic detection is designed and implemented in noninvasively imaged blood vessels in the skin in vivo. Dark-field optical illumination minimizes the interference caused by strong photoacoustic signals from superficial structures. A high-numerical-aperture acoustic lens provides high lateral resolution, 45–120μm in this system. A broadband ultrasonic detection system provides high axial resolution, estimated to be ∼15μm. The optical illumination and ultrasonic detection are in a coaxial confocal configuration for optimal image quality. The system is capable of imaging optical-absorption contrast as deep as 3mm in biological tissue.
424 citations
TL;DR: Experiments performed on turbid phantoms demonstrate that spatially modulated illumination facilitates quantitative wide-field optical property mapping and tomographic imaging in turbid media.
Abstract: Experiments performed on turbid phantoms demonstrate that spatially modulated illumination facilitates quantitative wide-field optical property mapping and tomographic imaging in turbid media.
421 citations
TL;DR: Experimental results indicate that the proposed novel approach has good performance in speckle noise removal, enhancement and segmentation of the various cellular layers of the retina using the STRATUSOCTTM system.
Abstract: Segmentation of retinal layers from OCT images is fundamental to diagnose the progress of retinal diseases. In this study we show that the retinal layers can be automatically and/or interactively located with good accuracy with the aid of local coherence information of the retinal structure. OCT images are processed using the ideas of texture analysis by means of the structure tensor combined with complex diffusion filtering. Experimental results indicate that our proposed novel approach has good performance in speckle noise removal, enhancement and segmentation of the various cellular layers of the retina using the STRATUSOCT™ system.
398 citations
TL;DR: Optical coherence tomography was similar to UBM in quantitative AC angle measurement and detection of narrow angles and is a promising method for screening individuals at risk for narrow angle glaucoma.
Abstract: Objective To assess the accuracy of classification of narrow anterior chamber (AC) angles using quantitative imaging by optical coherence tomography (OCT) and ultrasound biomicroscopy (UBM). Design Observational comparative study. Methods A high-speed (4000 axial scans/s) anterior segment OCT prototype was developed using a 1.3-μm light source. Seventeen normal subjects (17 eyes) and 7 subjects (14 eyes) with narrow angle glaucoma were enrolled. All subjects underwent gonioscopy, OCT, and UBM. Quantitative AC angle parameters (angle opening distance, angle recess area, and the trabecular-iris space area [a new parameter we have defined]) were measured from OCT and UBM images using proprietary processing software. Main Outcome Measures Specificity and sensitivity in identifying narrow angles with image-derived AC angle parameters. Results Eight of 31 eyes were classified as having narrow angles (Shaffer grade ≤1 in all quadrants). The AC angle parameters measured by both OCT and UBM had similar mean values, reproducibility, and sensitivity-specificity profiles. Both OCT and UBM showed excellent performance in identifying eyes with narrow angles. Areas under the receiver operating characteristic curves for these parameters were all in the range of 0.96 to 0.98. Conclusions Optical coherence tomography was similar to UBM in quantitative AC angle measurement and detection of narrow angles. In addition, it was easier to use and did not require contact with the eye. Optical coherence tomography is a promising method for screening individuals at risk for narrow angle glaucoma.
TL;DR: A simple calibration method using a fringe analysis technique for spectral rescaling is presented, which shows that the system sensitivity is experimentally determined to be 114 dB, and the three-dimensional OCT volumes reveal the structures of the anterior eye segments, which are difficult to observe in two- dimensional OCT images.
Abstract: A two- and three-dimensional swept source optical coherence tomography (SS-OCT) system, which uses a ready-to-ship scanning light source, is demonstrated. The light source has a center wavelength of 1.31 mum, -3 dB wavelength range of 110 nm, scanning rate of 20 KHz, and high linearity in frequency scanning. This paper presents a simple calibration method using a fringe analysis technique for spectral rescaling. This SS-OCT system is capable of realtime display of two-dimensional OCT and can obtain three-dimensional OCT with a measurement time of 2 s. In vivo human anterior eye segments are investigated two- and three-dimensionally. The system sensitivity is experimentally determined to be 114 dB. The three-dimensional OCT volumes reveal the structures of the anterior eye segments, which are difficult to observe in two-dimensional OCT images.
TL;DR: Spectral domain optical coherence tomography technology enables ophthalmic imaging with unprecedented simultaneous ultra- high speed and ultra-high resolution.
Abstract: Objective To introduce a new ophthalmic optical coherence tomography technology that allows unprecedented simultaneous ultra-high speed and ultra-high resolution. Methods Using a superluminescent diode source, a clinically viable ultra-high speed, ultra-high resolution spectral domain optical coherence tomography system was developed. Results In vivo images of the retina, the optic nerve head, and retinal blood flow were obtained at an ultra-high speed of 34.1 microseconds (ms) per A-scan, which is 73 times faster than commercially available optical coherence tomography instruments. Single images (B-scans) consisting of 1000 A-scans were acquired in 34.1 ms, allowing video rate imaging at 29 frames per second with an axial resolution of 6 μm. Using a different source in a slightly slower configuration, single images consisting of 500 A-scans were acquired in 34 ms, allowing imaging at 29 frames per second at an axial resolution of 3.5 μm, which is 3 times better than commercially available optical coherence tomography instruments. The amount of energy directed into the eye in both cases, 600 μW, is less than that of the Stratus OCT3 and is safe for intrabeam viewing for up to 8 hours at the same retinal location. Conclusion Spectral domain optical coherence tomography technology enables ophthalmic imaging with unprecedented simultaneous ultra-high speed and ultra-high resolution.
TL;DR: A novel microscopy technique based on depth-resolved phase information provided by common path spectral-domain optical coherence tomography that can measure minute phase variations caused by changes in refractive index and thickness inside the specimen is described.
Abstract: We describe a novel microscopy technique for quantitative phase-contrast imaging of a transparent specimen. The technique is based on depth-resolved phase information provided by common path spectral-domain optical coherence tomography and can measure minute phase variations caused by changes in refractive index and thickness inside the specimen. We demonstrate subnanometer level path-length sensitivity and present images obtained on reflection from a known phase object and human epithelial cheek cells.
TL;DR: In this article, a phase-sensitive technique called spectral-domain phase microscopy (SDPM) is proposed for the detection of nanometer-scale motions in living cells, and a shot-noise limit to the displacement sensitivity of this technique is derived.
Abstract: Broadband interferometry is an attractive technique for the detection of cellular motions because it provides depth-resolved phase information via coherence gating. We present a phase-sensitive technique called spectral-domain phase microscopy (SDPM). SDPM is a functional extension of spectral-domain optical coherence tomography that allows for the detection of nanometer-scale motions in living cells. The sensitivity of the technique is demonstrated, and its calibration is verified. A shot-noise limit to the displacement sensitivity of this technique is derived. Measurement of cellular dynamics was performed on spontaneously beating cardiomyocytes isolated from chick embryos.
TL;DR: A novel spectral domain OCT (SD-OCT) camera based on a free-space parallel illumination architecture and equipped with adaptive optics was developed and sufficient to observe the interface between the inner and outer segments of individual photoreceptor cells, resolved in both lateral and axial dimensions.
Abstract: Although optical coherence tomography (OCT) can axially resolve and detect reflections from individual cells, there are no reports of imaging cells in the living human retina using OCT. To supplement the axial resolution and sensitivity of OCT with the necessary lateral resolution and speed, we developed a novel spectral domain OCT (SD-OCT) camera based on a free-space parallel illumination architecture and equipped with adaptive optics (AO). Conventional flood illumination, also with AO, was integrated into the camera and provided confirmation of the focus position in the retina with an accuracy of +/-10.3 mum. Short bursts of narrow B-scans (100x560 mum) of the living retina were subsequently acquired at 500 Hz during dynamic compensation (up to 14 Hz) that successfully corrected the most significant ocular aberrations across a dilated 6 mm pupil. Camera sensitivity (up to 94 dB) was sufficient for observing reflections from essentially all neural layers of the retina. Signal-to-noise of the detected reflection from the photoreceptor layer was highly sensitive to the level of cular aberrations and defocus with changes of 11.4 and 13.1 dB (single pass) observed when the ocular aberrations (astigmatism, 3rd order and higher) were corrected and when the focus was shifted by 200 mum (0.54 diopters) in the retina, respectively. The 3D resolution of the B-scans (3.0x3.0x5.7 mum) is the highest reported to date in the living human eye and was sufficient to observe the interface between the inner and outer segments of individual photoreceptor cells, resolved in both lateral and axial dimensions. However, high contrast speckle, which is intrinsic to OCT, was present throughout the AO parallel SD-OCT B-scans and obstructed correlating retinal reflections to cell-sized retinal structures.
TL;DR: High-speed UHR OCT offers unprecedented, realistic, 3-D imaging of ocular diseases at all epi-, intra- and subretinal levels and allows a comprehensive analysis of focal and diffuse diseases, as well as identification of dynamic pathomechanisms.
Abstract: PURPOSE. To demonstrate a new generation of three-dimensional (3-D) ultrahigh-resolution optical coherence tomography (UHR OCT) technology for visualization of macular diseases. METHODS. One hundred forty eyes with a distinct disease in each of the posterior pole compartments were examined with 3-D UHR OCT. 3-D imaging was performed with a high axial resolution of 3 μm with a compact, commercially available, ultra-broad-bandwidth (160 nm) titanium:sapphire laser at a video rate of up to 25 B-scans/s. Each tomogram consisted of 1024 X 1024 pixels, resulting in 25 megavoxels/s. RESULTS. 3-D UHR OCT offers high-precision 3-D visualization of macular diseases at all structural levels. The UHR modality allows identification of the contour of the hyaloid membrane, tractive forces of epiretinal membranes, and changes within the inner limiting membrane. The system provides quality 3-D images of the topographic dynamics of traction lines from the retinal surface down to the level of the photoreceptor segments. Intraretinal diseases are identified by their specific location in different layers of the neurosensory ultrastructure. Photoreceptor inner and outer segments are clearly delineated in configuration and size, with a characteristic peak in the subfoveal area. The microarchitecture of choroidal neovascularization is distinctly imaged, related leakage can be identified, and the volume can be quantified. CONCLUSIONS. High-speed UHR OCT offers unprecedented, realistic, 3-D imaging of ocular diseases at all epi-, intra- and subretinal levels. A complete 3-D data set of the macular layers allows a comprehensive analysis of focal and diffuse diseases, as well as identification of dynamic pathomechanisms.
TL;DR: A novel swept-laser-based Fourier-domain optical coherence tomography system using an electro-optic phase modulator and elimination of low-frequency noises resulting from dc and autocorrelation terms increased the sensitivity by 20 dB.
Abstract: A novel swept-laser-based Fourier-domain optical coherence tomography system using an electro-optic phase modulator was demonstrated. The imaging range was doubled by cancellation of the mirror image. The elimination of low-frequency noises resulting from dc and autocorrelation terms increased the sensitivity by 20 dB.
TL;DR: The system uses two spectrometers, one for each polarization channel, that operate in parallel at 20000 A-lines/s each and provides reflectivity, retardation, and cumulative optic axis orientation simultaneously.
Abstract: We developed a high-speed polarization sensitive optical coherence tomography (PS-OCT) system for retinal imaging based on spectral domain OCT. The system uses two spectrometers, one for each polarization channel, that operate in parallel at 20000 A-lines/s each. It provides reflectivity, retardation, and cumulative optic axis orientation simultaneously. We present our instrument and discuss the requirements for the alignment of the two spectrometers specific for our setup. We show 2D spectral domain PS-OCT images and – to the best of our knowledge – the first 3D spectral domain PS-OCT data sets in form of fly-through movies and volume rendered data sets recorded in human retina in vivo.
Patent•
28 Jun 2005
TL;DR: An optical fiber scanner is used for multiphoton excitation imaging, optical coherence tomography, or for confocal imaging in which transverse scans are carried out at a plurality of successively different depths within tissue.
Abstract: An optical fiber scanner is used for multiphoton excitation imaging, optical coherence tomography, or for confocal imaging in which transverse scans are carried out at a plurality of successively different depths within tissue The optical fiber scanner is implemented as a scanning endoscope using a cantilevered optical fiber that is driven into resonance or near resonance by an actuator The actuator is energized with drive signals that cause the optical fiber to scan in a desired pattern at successively different depths as the depth of the focal point is changed Various techniques can be employed for depth focus tracking at a rate that is much slower than the transverse scanning carried out by the vibrating optical fiber The optical fiber scanner can be used for confocal imaging, multiphoton fluorescence imaging, nonlinear harmonic generation imaging, or in an OCT system that includes a phase or frequency modulator and delay line
TL;DR: The advanced versions of OCT technique might not only lead to significant new insights in skin physiology and pathology, but also in diagnosis and therapeutic control of cutaneous disorders with respect to non-invasive diagnosis of conditions and monitoring of disease activity in addition to treatment effects over time.
TL;DR: High speed, three-dimensional OCT imaging can provide comprehensive data which combines the advantages of optical coherence tomography and microscopy in a single system.
Abstract: We demonstrate high resolution, three-dimensional OCT imaging with a high speed, frequency swept 1300 nm laser source. A new external cavity semiconductor laser design, optimized for application to swept source OCT, is discussed. The design of the laser enables adjustment of an internal spectral filter to change the filter bandwidth and provides a robust bulk optics design. The laser generates ~30 mW instantaneous peak power at an effective 16 kHz sweep rate with a tuning range of ~133 nm full width. In frequency domain reflectometry and OCT applications, 109 dB sensitivity and ~10 microm axial resolution in tissue can be achieved with the swept laser. The high imaging speeds enable three-dimensional OCT imaging, including zone focusing or C-mode imaging and image fusion to acquire large depth of field data sets with high resolution. In addition, three-dimensional OCT data provides coherence gated en face images similar to optical coherence microscopy (OCM) and also enables the generation of images similar to confocal microscopy by summing signals in the axial direction. High speed, three-dimensional OCT imaging can provide comprehensive data which combines the advantages of optical coherence tomography and microscopy in a single system.
TL;DR: Ultrahigh-resolution OCT images can provide a baseline for defining the interpretation of standard-resolution images, thus enhancing the clinical utility of standard OCT imaging and providing additional information on macular disease morphology that promises to improve understanding of disease progression and management.
TL;DR: The operation of a turnkey 1300-nm swept laser source is demonstrated and a novel optoelectronic technique that allows for even sampling of the swept source OCT signal in k space is described.
Abstract: The increased sensitivity of spectral domain optical coherence tomography (OCT) has driven the development of a new generation of technologies in OCT, including rapidly tunable, broad bandwidth swept laser sources and spectral domain OCT interferometer topologies. In this work, the operation of a turnkey 1300-nm swept laser source is demonstrated. This source has a fiber ring cavity with a semiconductor optical amplifier gain medium. Intracavity mode selection is achieved with an in-fiber tunable fiber Fabry-Perot filter. A novel optoelectronic technique that allows for even sampling of the swept source OCT signal in k space also is described. A differential swept source OCT system is presented, and images of in vivo human cornea and skin are presented. Lastly, the effects of analog-to-digital converter aliasing on image quality in swept source OCT are discussed.
TL;DR: A fundus image similar to the intensity image produced by a scanning laser ophthalmoscope was generated from the same spectra that were used for generating the OCT sectional images immediately after the spectra were collected, which offers perfect spatial registration between the sectional OCT images and the fundu image.
Abstract: A high-speed spectral-domain optical coherence tomography (OCT) system was built to image the human retina in vivo. A fundus image similar to the intensity image produced by a scanning laser ophthalmoscope (SLO) was generated from the same spectra that were used for generating the OCT sectional images immediately after the spectra were collected. This function offers perfect spatial registration between the sectional OCT images and the fundus image, which is desired in ophthalmology for monitoring data quality, locating pathology, and increasing reproducibility. This function also offers a practical way to detect eye movements that occur during the acquisition of the OCT image. The system was successfully applied to imaging human retina in vivo.
TL;DR: Monodispersed gold nanocages of an approximately 35 nm edge length exhibit strong optical resonance, with the peak wavelength tunable in the near-infrared range, revealing an absorption cross section approximately 5 orders of magnitude larger than conventional dyes.
Abstract: We describe gold nanocages as a new class of potential contrast agent for spectroscopic optical coherence tomography (OCT). Monodispersed gold nanocages of an approximately 35 nm edge length exhibit strong optical resonance, with the peak wavelength tunable in the near-infrared range. We characterized the optical properties of the nanocage by using OCT experiments along with numerical calculations, revealing an absorption cross section approximately 5 orders of magnitude larger than conventional dyes. Experiments with tissue phantoms demonstrated that the nanocages provide enhanced contrast for spectroscopic as well as conventional intensity-based OCT imaging.
Patent•
01 Jul 2005TL;DR: In this paper, an alternative Fourier domain optical coherence system (FD-OCT) and its associated method is presented. The system comprises a swept multi-wavelength laser, an optical interferometer and a multi-channel receiver.
Abstract: The present invention is an alternative Fourier domain optical coherence system (FD-OCT) and its associated method. The system comprises a swept multi-wavelength laser, an optical interferometer and a multi-channel receiver. By employing a multi-wavelength laser, the sweeping range for each lasing wavelength is substantially reduced as compared to a pure swept single wavelength laser that needs to cover the same overall spectral range. The overall spectral interferogram is divided over the individual channels of the multi-channel receiver and can be re-constructed through processing of the data from each channel detector. In addition to a substantial increase in the speed of each axial scan, the cost of invented FD-OCT system can also be substantially less than that of a pure swept source OCT or a pure spectral domain OCT system.
TL;DR: The two peer approaches to SDOCT are compared in speed, scan depth range, complexity, spectral regions of operation, and methods of detection and possible directions that this research may take in the near future are discussed.
Abstract: This paper reviews the current state of research in spectral domain optical coherence tomography (SDOCT). SDOCT is an interferometric technique that provides depth-resolved tissue structure information encoded in the magnitude and delay of the back-scattered light by spectral analysis of the interference fringe pattern. There are two approaches to SDOCT--one that uses a broadband source and a spectrometer to measure the interference pattern as a function of wavelength and the other that utilizes a narrowband tunable laser that is swept linearly in k approximately 1/lambda space during spectral fringe data acquisition. Unlike time domain (TD) OCT, the reference arm is stationary in both SDOCT methods, which allows for ultra high-speed OCT imaging. Owing to its high speed and superior sensitivity, SDOCT has become indispensable in biomedical imaging applications. After a brief introduction and a discussion on sensitivity advantage, methods of implementation of the two SDOCT schemes will be presented. The two peer approaches are compared in speed, scan depth range, complexity, spectral regions of operation, and methods of detection. The review also discusses OCT enhancements and functional methods based on SDOCT format and concludes with possible directions that this research may take in the near future.
TL;DR: Improved retinal imaging enabled assignment of the OCT image to retinal anatomy particularly at the outer layer of the photoreceptors and the retinal pigment epithelium, both in the healthy eye and in pathology.
Abstract: Aims: To describe a method for computerised alignment and averaging of sequences in optical coherence tomography (OCT) B-scans and to present selected clinical observations based on the resulting improvement in retinal imaging.
Methods: A methodological study and retrospective investigation of selected cases. Five human subjects were included, one healthy subject, two patients with central serous chorioretinopathy, one patient with branch retinal vein occlusion, and one patient with cilioretinal artery pseudo-occlusion. Based on computerised alignment of sets of B-scans obtained at identical retinal locations, average OCT images were produced and displayed in false colour or grayscale. These enhanced tomograms were compared with other morphological and functional characteristics.
Results: Improved retinal imaging enabled assignment of the OCT image to retinal anatomy particularly at the outer layer of the photoreceptors and the retinal pigment epithelium, both in the healthy eye and in pathology. Identification of both post-oedematous structural disorganisation as well as post-ischaemic attenuation of the inner retina was superior to standard OCT images.
Conclusions: Averaging of multiple OCT B-scans enhances the quality of retinal imaging sufficiently to reveal new details of retinal pathophysiology. Using the technique on OCT3 scans enables visualisation of details comparable with the results obtained using ultra high resolution OCT.
TL;DR: A method to determine the retinal nerve fiber layer (RNFL) thickness in OCT images based on anisotropic noise suppression and deformable splines and an integrated reflectance map of the retina to facilitate clinical interpretation of the OCT data is introduced.
Abstract: We introduce a method to determine the retinal nerve fiber layer (RNFL) thickness in OCT images based on anisotropic noise suppression and deformable splines. Spectral-Domain Optical Coherence Tomography (SDOCT) data was acquired at 29 kHz A-line rate with a depth resolution of 2.6 mum and a depth range of 1.6 mm. Areas of 9.6x6.4 mm2 and 6.4x6.4 mm2 were acquired in approximately 6 seconds. The deformable spline algorithm determined the vitreous-RNFL and RNFL-ganglion cell/inner plexiform layer boundary, respectively, based on changes in the reflectivity, resulting in a quantitative estimation of the RNFL thickness. The thickness map was combined with an integrated reflectance map of the retina and a typical OCT movie to facilitate clinical interpretation of the OCT data. Large area maps of RNFL thickness will permit better longitudinal evaluation of RNFL thinning in glaucoma.