Optical coherence tomography Research Papers (original) (raw)

All subjects were followed up for a minimum of 6 months and up to 2.7 years. Methods: The electronic stimulator and antenna of the implant were sutured onto the sclera using an encircling silicone band. Next, a pars plana vitrectomy was performed, and the electrode array and cable were introduced into the eye via a pars plana sclerotomy. The microelectrode array then was tacked to the epiretinal surface. Main Outcome Measures: The primary safety end points for the trial were the number, severity, and relation of adverse events. Principal performance end points were assessments of visual function as well as performance on orientation and mobility tasks. Results: Subjects performed statistically better with the system on versus off in the following tasks: object localization (96% of subjects), motion discrimination (57%), and discrimination of oriented gratings (23%). The best recorded visual acuity to date is 20/1260. Subjects' mean performance on orientation and mobility tasks was significantly better when the system was on versus off. Seventy percent of the patients did not have any serious adverse events (SAEs). The most common SAE reported was either conjunctival erosion or dehiscence over the extraocular implant and was treated successfully in all subjects except in one, who required explantation of the device without further complications. Conclusions: The long-term safety results of Second Sight's retinal prosthesis system are acceptable, and most subjects with profound visual loss perform better on visual tasks with system than without it.

- by
- •
- Ophthalmology, Blindness, Optical coherence tomography, Medicine

PURPOSE: To develop an optical coherence tomography (OCT) classification system that monitors the response of eyes treated with photodynamic therapy (PDT) with verteporfin for subfoveal choroidal neovascularization (CNV) from age-related... more

- by Carmen Puliafito
- •
- Optical coherence tomography, Porphyrins, Tomography, Photodynamic Therapy

We describe a capsulotomy technique to maintain the anterior chamber and pull the capsule disk gently centrally to separate the free edge from the surrounding peripheral capsule and to confirm there is a continuous 360-degree cut with a... more

To evaluate posterior capsule opacification (PCO) in humans after cataract surgery with intraocular lens (IOL) implantation, by using optical coherence tomography (OCT-1). METHODS. Sixty-six eyes with PCO and 20 eyes with a normal posterior capsule were analyzed. A 3-mm-long horizontal scan of the posterior capsule was obtained. Measurements at three points and their average were recorded. Intraoperator and interoperator reliabilities were assessed. Investigated was peak intensity (PI) and posterior capsule thickening (PCT), with PCT indicating the distance between two reflectivity spikes, with an approximate axial resolution of 10 m. Results were compared with visual acuity (VA) and PCO type. RESULTS. Intraoperator reliability was 0.59 and 0.97 for average PI and PCT, respectively. The interoperator concordance correlation coefficient was 0.70 and 0.82 for average PI and PCT, respectively. Median (interquartile range) intensities of the reflectivity spike were 16.88 (dB) (range, 12.88 -20.41) and 11.9 (8.58 -14.28), respectively, in the PCO and control eyes (P ϭ 0.001). PCT was found in PCO eyes (median: 86.13 m; range, 46.33-115.33), whereas no second spike appeared in control eyes (P ϭ 0.001). The area under the receiver operating characteristic curve of the average PCT for differentiating pearl-type from fibrosis-type PCO was 0.87 (P ϭ 0.001). For a cutoff point of 55.3 m, the sensitivity was 97.5%, and the specificity was 69%. Worse VA correlated significantly only with larger PCT (r o ϭ 0.66; P ϭ 0.01).

- by Aurora Alvarez
- •
- Optical coherence tomography, Adolescent, Visual acuity, Biological Sciences

PURPOSE. To correlate the dimension of the visual field (VF) tested by Goldman kinetic perimetry with the extent of visi- bility of the highly reflective layer between inner and outer segments of photoreceptors (IOS) seen in optical coherence tomography (OCT) images in patients with retinitis pigmen- tosa (RP). METHODS. In a retrospectively designed cross-sectional study, 18 eyes of 18 patients

We demonstrate a new implementation of complex spectral optical coherence tomography (OCT) in biomedical imaging. By reconstruction of both amplitude and phase we are able to use the negative and positive optical path differences to get images of objects of considerable thickness. An accompanying reduction of coherent noise improves the quality of the images. The property of the complex spectral OCT that permits the measurement range to be increased and permits the simultaneous use of phase and amplitude in spectral systems was not described previously. To show the potential of this technique we measured an anterior chamber of a porcine eye in vitro.

- by Amod Gupta
- •
- Immunology, Optical coherence tomography, Adolescent, Medicine

We determine temperature effect on the absorption and reduced scattering coefficients (a and s Ј) of human forearm skin. Optical and thermal simulation data suggest that a and s Ј are determined within a temperature-controlled depth of Ϸ2 mm. Cutaneous s Ј change linearly with temperature. Change in a was complex and irreversible above body normal temperatures. Light penetration depth (␦) in skin increased on cooling, with considerable person-toperson variations. We attribute the effect of temperature on s Ј to change in refractive index mismatch, and its effect on a to perfusion changes. The reversible temperature effect on s Ј was maintained during more than 90 min. contact between skin and the measuring probe, where temperature was modulated between 38 and 22°C for multiple cycles While temperature modulated s Ј instantaneously and reversibly, a exhibited slower response time and consistent drift. There was a statistically significant upward drift in a and a mostly downward drift in s Ј over the contact period. The drift in temperature-induced fractional change in s Ј was less statistically significant than the drift in s Ј. ⌬ s Ј values determined under temperature modulation conditions may have less nonspecific drift than s Ј which may have significance for noninvasive determination of analytes in human tissue.

- by Shujen Yeh
- •
- Biomedical Engineering, Optical coherence tomography, Near Infrared, Modulation

The objective of this work was to develop a LIDAR-like equation model to analyze the measured Optical coherence tomography (OCT) signal and determine the total extinction coefficient of a scattering sample. OCT is an interferometric technique that explore sample backscattering feature to acquire in depth crosssection images using a low coherence light source. Although, almost of the OCT applications are intended to generate images for diagnostic, similar to histological images, but the backscattering signal carries much more information. The backscattering problem is similar to those found on LIDAR (Light Detection And Ranging) problem, this similar situation indicate a path that should be followed to solve the OCT problem.

- by Niklaus Wetter
- •
- Optical coherence tomography, Proceedings, Optical Properties, Double Layer

Polarization-sensitive optical coherence tomography ͑PS-OCT͒ and near-infrared ͑NIR͒ imaging are promising new technologies under development for monitoring early carious lesions. Fluorosis is a growing problem in the United States, and the more prevalent mild fluorosis can be visually mistaken for early enamel demineralization. Unfortunately, there is little quantitative information available regarding the differences in optical properties of sound enamel, enamel developmental defects, and caries. Thirty extracted human teeth with various degrees of suspected fluorosis were imaged using PS-OCT and NIR. An InGaAs camera and a NIR diode laser were used to measure the optical attenuation through transverse tooth sections ͑ϳ200 m͒. A digital microradiography system was used to quantify the enamel defect severity by measurement of the relative mineral loss for comparison with optical scattering measurements. Developmental defects were clearly visible in the polarizationresolved OCT images, demonstrating that PS-OCT can be used to nondestructively measure the depth and possible severity of the defects. Enamel defects on whole teeth that could be imaged with high contrast with visible light were transparent in the NIR. This study suggests that PS-OCT and NIR methods may potentially be used as tools to assess the severity and extent of enamel defects.

The application of physics to art history, art conservation and archaeology is currently a growing area of research. Astronomy and astrophysics have made significant contributions to imaging science which has in turn contributed to the developments of many other fields ranging from biological science to the study of art history, archaeology and art conservation. This paper will discuss how knowledge traditionally associated with astrophysics have made impact on the
study of cultural heritage. Examples will be drawn from recent research carried out in my research group.

- by Haida Liang
- •
- Cultural Heritage, Archaeological Science, Optical coherence tomography, Astrophysics

Oxidative hair dyes can damage the hair, since these chemical procedures are involved to change the fiber structure and therefore changes in their mechanical and surface properties. Evaluate and compare the effect of the two colors of oxidative hair dye emulsions on Caucasian hair. This research analyzed the Dark brown hair untreated (I); Dark brown hair treated with light brown dye (II); Dark brown hair treated with light blond dye (III); Light blond hair untreated (IV); Light blond hair treated with light brown dye (V); Light blond hair treated with light blond dye (VI) on Caucasian hair. The hair samples were submitted to breaking strength, color, and optical coherence tomography (OCT) analysis. For the breaking strength assay no presented statistically significant differences between treatments. The parameters of color and brightness can differ in some hair dye formulations, but also the hair type can respond differently. The OCT images of the sample I and IV was possible observed, clearly Medulla and Cortex, which was not observed clearly after treatment with both oxidative hair dye colors. Based on the results, the oxidative hair dyes increased alteration in color and ultrastructure of hair.

- by Maria Velasco and +2
- •
- Optical coherence tomography, Hair, Clinical Sciences, Image Enhancement

With the introduction of spectral-domain optical coherence tomography (OCT), much larger image datasets are routinely acquired compared to what was possible using the previous generation of time-domain OCT. Thus, the need for 3-D segmentation methods for processing such data is becoming increasingly important. We report a graph-theoretic segmentation method for the simultaneous segmentation of multiple 3-D surfaces that is guaranteed to be optimal with respect to the cost function and that is directly applicable to the segmentation of 3-D spectral OCT image data. We present two extensions to the general layered graph segmentation method: the ability to incorporate varying feasibility constraints and the ability to incorporate true regional information. Appropriate feasibility constraints and cost functions were learned from a training set of 13 spectral-domain OCT images from 13 subjects. After training, our approach was tested on a test set of 28 images from 14 subjects. An overall mean unsigned border positioning error of 5 69 2 41 m was achieved when segmenting seven surfaces (six layers) and using the average of the manual tracings of two ophthalmologists as the reference standard. This result is very comparable to the measured interobserver variability of 5 71 1 98 m.

- by Stephen Russell
- •
- Engineering, Algorithms, Medical Imaging, Optical coherence tomography

We describe a polarization sensitive spectral domain optical coherence tomography technique based on a single camera spectrometer that includes a multiplexed custom grating, camera lenses, and a high-speed three-line CCD camera. Two orthogonally polarized beams could be separately taken by two lines of the camera as a result of vertically different incident angles. The system could provide the imaging capabilities of a full camera speed and increased measurable depth. The proposed optical coherence tomography system could make a distinction between the normal muscle and cancerous tissue from the chest of a DSred GFP mouse and the OCT images were compared with those of in vivo confocal microscopy.

- by Ferdinand Schlanitz
- •
- Fluorescence Microscopy, Optical coherence tomography, Mice, Muscles

Optical Coherence Tomography (OCT) is an imaging technique offering a non-invasive alternative to the traditional analysis of artworks by means of sampling. A cross-section photomicrograph of a sample collected from a painting has its own limitations, mostly due to the restricted number of samples it is possible to collect. There is a need, therefore, for non-invasive

- by Piotr Targowski
- •
- Computer Science, Physics, Cardiology, Forecasting
- by Pearse A Keane
- •
- Ophthalmology, Optical coherence tomography, Retinal detachment, Prednisolone

A 63-year-old woman presented with proliferative diabetic retinopathy with extensive posterior neovascularization in both eyes. Visual acuities were 20/40 in the right eye and 20/400 in the left eye with eccentric fixation. Tractional retinoschisis in the left eye that initially spared the fovea progressed over 3 years to involve the entire macula. Findings were documented by optical coherence tomography. No surgical intervention was offered. Tractional retinoschisis in proliferative diabetic retinopathy may become progressive due to cicatricial contraction of the posterior hyaloid face. [Ophthalmic Surg Lasers Imaging 2010;41:e1-e3.]

The incidence of pathological infections in many fruit plantations is high and leads to a large portion of waste. Venturianashicola caused pear scab disease that infects almost all parts of the tree, foliage, flowers, and fruits. With the increasing interest in food security, non-destructive initial inspection methods have been focused, recently. It is well recognized that optical coherence tomography (OCT) is capable of revealing cross-sectional structures, which can be applied to diagnose plant diseases. Hence, optically screened morphological changes of pear scab infected Asianpear (Pyruspyrifolia) leaves and fruits were demonstratedusing OCT. The results suggest that infected pear fruits and leaf samples can be precisely identified through the internal structural changes, and this may potentially apply for a better control of the spread of disease in plantations.

- by Naresh Kumar Ravichandran and +2
- •
- Optical coherence tomography

Optics has played a key role in the rapidly developing field of molecular imaging. The spectroscopic nature and high-resolution imaging capabilities of light provide a means for probing biological morphology and function at the cellular... more

Aims: High rates of restenosis and stent thrombosis are still often observed after bifurcation stenting despite the recommended stent post-dilatation using the kissing balloon (KB) technique. We investigated the potential benefits of a final post-dilatation step in bifurcation stenting with a balloon that respects the natural diameter ratio of the proximal and distal vessels in bifurcations (Murray's law).

A custom-developed ultrahigh resolution optical coherence tomography with an axial resolution of 1.1 μm in corneal tissue was used to characterize thickness and light scatter of the epithelium and Bowman's layer in keratoconic (KC) cornea noninvasively. A 4-mm wide vertical corneal section around the apex in nine KC and eight normal eyes was imaged in vivo. The epithelium and Bowman's layer were visualized and their thickness profiles were quantified. Scatter was quantified based on the sensitivity normalized mean signal intensity distribution. Average mean thickness of the epithelium and Bowman's layer in KC eyes was significantly smaller ðp < 0.05Þ than the normal eyes. The epithelium thickness variation across a central 3-mm cornea was significantly larger in KC eyes than in normal eyes. The scatter in KC eyes was significantly increased only for Bowman's layer. The changes observed in this study could improve our understanding of the underlying disease mechanism of KC and can provide new indications for early disease diagnosis.

- by Rahul Yadav
- •
- Engineering, Materials Science, Biomedical Engineering, Optical coherence tomography

Aims To study the effects of intravitreal bevacizumab (Avastin) on retinal neovascularization (RN) in patients with proliferative diabetic retinopathy (PDR). Methods Retrospective study of patients with RN due to PDR who were treated with at least one intravitreal injection of 1.25 or 2.5 mg of bevacizumab. Patients underwent ETDRS best-corrected visual acuity (BCVA) testing, ophthalmoscopic examination, optical coherence tomography (OCT), and fluorescein angiography (FA) at baseline and follow-up visits.

- by Mauricio Maia and +1
- •
- Immunology, Treatment Outcome, Optical coherence tomography, Visual acuity

Objectives To assess the effect of image registration and averaging on the visualization and quantification of the radial peripapillary capillary (RPC) network on optical coherence tomography angiography (OCTA). Methods Twenty-two healthy controls were imaged with a commercial OCTA system (AngioVue, Optovue, Inc.). Ten 10x10˚scans of the optic disc were obtained, and the most superficial layer (50-μm slab extending from the inner limiting membrane) was extracted for analysis. Rigid registration was achieved using ImageJ, and averaging of each 2 to 10 frames was performed in five~2x2˚regions of interest (ROI) located 1˚from the optic disc margin. The ROI were automatically skeletonized. Signal-to-noise ratio (SNR), number of endpoints and mean capillary length from the skeleton, capillary density, and mean intercapillary distance (ICD) were measured for the reference and each averaged ROI. Repeated measures analysis of variance was used to assess statistical significance. Three patients with primary open angle glaucoma were also imaged to compare RPC density to controls. Results Qualitatively, vessels appeared smoother and closer to histologic descriptions with increasing number of averaged frames. Quantitatively, number of endpoints decreased by 51%, and SNR, mean capillary length, capillary density, and ICD increased by 44%, 91%, 11%, and 4.5% from single frame to 10-frame averaged, respectively. The 10-frame averaged images from the glaucomatous eyes revealed decreased density correlating to visual field defects and retinal nerve fiber layer thinning.

- by Richard B Rosen
- •
- Optical coherence tomography, Multidisciplinary, Capillaries, Glaucoma

Citation: Aboshiha J, Kumaran N, Kalitzeos A, Hogg C, Rubin G, Michaelides M. A quantitative and qualitative exploration of photoaversion in achromatopsia. Invest Ophthalmol PURPOSE. Photoaversion (PA) is a disabling and ubiquitous feature of achromatopsia (ACHM). We aimed to help define the characteristics of this important symptom, and present the first published assessment of its impact on patients' lives, as well as quantitative and qualitative PA assessments.

- by Chris Hogg
- •
- Finance, Qualitative methodology, Banking, Gender

This study sought to investigate the in-scaffold vascular response (SVR) and edge vascular response (EVR) after implantation of an everolimus-eluting bioresorbable scaffold (BRS) using serial optical coherence tomography (OCT) imaging. Although studies using intravascular ultrasound have evaluated the EVR in metal stents and BRSs, there is a lack of OCT-based SVR and EVR assessment after BRS implantation. In the ABSORB Cohort B (ABSORB Clinical Investigation, Cohort B) study, 23 patients (23 lesions) in Cohort B1 and 17 patients (18 lesions) in Cohort B2 underwent truly serial OCT examinations at 3 different time points (Cohort B1: post-procedure, 6 months, and 2 years; B2: post-procedure, 1 year, and 3 years) after implantation of an 18-mm scaffold. A frame-by-frame OCT analysis was performed at the 5-mm proximal, 5-mm distal edge, and 2-mm in-scaffold margins, whereas the middle 14-mm in-scaffold segment was analyzed at 1-mm intervals. The in-scaffold mean luminal area significant...

- by Yoshinobu Onuma
- •
- Treatment Outcome, Optical coherence tomography, Aged, Time Factors

PURPOSE: To evaluate the risk factors for interface haze formation after thin-flap femtosecond laser -laser in situ keratomileusis (LASIK). • DESIGN: Prospective case series. • METHODS: One hundred and ninety-nine consecutive eyes that underwent femtosecond laser LASIK with a LADAR 4000 excimer laser (Alcon Laboratories, Fort Worth, Texas, USA), were analyzed from January 1 to April 30, 2008. Treated eyes were divided into 2 groups according to desired flap thickness: 90 m (106 eyes), and 100 to 110 m (93 eyes). Cycloplegic refraction, spherical equivalent (SE), uncorrected visual acuity, best spectacle-corrected visual acuity (BSCVA), depth of ablation, central corneal thickness, flap thickness (optical coherence tomography), Scheimpflug images (Pentacam; Oculus Inc, Lynnwood, Washington, USA), and light scattering were assessed in all eyes that developed haze postoperatively. • RESULTS: Haze was observed in 32 eyes treated for moderate to high myopia (SE ؊6.23 ؎ 1.67 diopters and depth of ablation 94.6 ؎ 22.9m) at 3 months postoperatively. Ultra-thin IntraLASIK flaps (<90 m) and younger age were strongly associated with risk of postoperative haze (P ‫؍‬ .003 and P ‫؍‬ .01, respectively). SE, depth of ablation, and self-reported history of dry eyes were not independently associated with an increased risk of corneal haze. Patients who developed any degree of haze had significantly higher logarithmic value of scatter (log S) values (mean difference ‫42.0؍‬ units, P < .0005) compared with those who did not develop haze. The mean postoperative BSCVA was good in all eyes with haze (logarithm of the minimal angle of resolution 0.05 ؎ 0.04). • CONCLUSION: Interface haze is associated with an ultrathin femtosecond laser flap setting of 90 m and younger age among eyes following LASIK for myopia. (Am J Ophthalmol 2009;147:966 -972.

- by Karolinne Rocha
- •
- Ophthalmology, Surgery, Photography, Treatment

To assess whether and to what extent macro- and/or microstructural modifications are present in the brain of patients with selective central visual loss due to a juvenile macular degeneration, Stargardt's disease (STGD), taking advantage of the complementary information provided by voxel-based morphometry (VBM) and diffusion tensor imaging (DTI). Eighteen patients with clinical and molecular diagnosis of STGD related to ABCA4 mutations and 23 normally sighted volunteers of comparable age and sex were enrolled. Structural T1-weighted (T1w) volumes, for brain tissue volume assessment by segmentation, and DTI, for the investigation of diffusivity parameters via a tract-based spatial statistics (TBSS) procedure, were acquired at 3 Tesla in all subjects. All patients underwent a complete ophthalmologic examination, including best-corrected visual acuity (BCVA), biomicroscopy, ophthalmoscopy, electroretinography (ERG), microperimetry, and optical coherence tomography (OCT). Correlatio...

Medical laser applications based on widespread research and development is a very dynamic and increasingly popular field from an ecological as well as an economic point of view. Conferences and personal communication are necessary to identify specific requests and potential unmet needs in this multi-and interdisciplinary discipline. Precise gathering of all information on innovative, new, or renewed techniques is necessary to design medical devices for introduction into clinical applications and finally to become established for routine treatment or diagnosis. Five examples of successfully addressed clinical requests are described to show the long-term endurance in developing light-based innovative clinical concepts and devices. Starting from laboratory medicine, a noninvasive approach to detect signals related to iron deficiency is shown. Based upon photosensitization, fluorescence-guided resection had been discovered, opening the door for photodynamic approaches for the treatment of brain cancer. Thermal laser application in the nasal cavity obtained clinical acceptance by the introduction of new laser wavelengths in clinical consciousness. Varicose veins can be treated by innovative endoluminal treatment methods, thus reducing side effects and saving time. Techniques and developments are presented with potential for diagnosis and treatment to improve the clinical situation for the benefit of the patient.

- by Lothar Lilge
- •
- Engineering, Biomedical Engineering, Optical coherence tomography, Medicine

PURPOSE: To evaluate the safety and efficacy of phacoemulsification, intraocular lens (IOL) implantation, and a single intravitreal injection of bevacizumab in patients with coexisting visually significant cataract and subfoveal... more

- by Nicola Cardascia
- •
- Optical coherence tomography, Visual acuity, Macular Degeneration, Cataract

To assess corneal anatomic changes after LASIK with a high-speed corneal and anterior segment optical coherence tomography (CAS-OCT) system. Cross-sectional observational study. Fifty-one eyes of 26 healthy persons undergoing LASIK. The CAS-OCT prototype operated at a 1.3-mum wavelength and 2000 axial scans/second. The corneas were scanned with a flap profile pattern (horizontal line, 512 axial scans) and a flap map pattern (4 radials, 256 axial scans each). Both patterns are 8 mm long and are centered on the corneal vertex. LASIK flaps were created using either a mechanical microkeratome (Hansatome; Bausch & Lomb, Inc., Rochester, NY) or a femtosecond laser (Pulsion; IntraLase Corp., Irvine, CA). Intraoperative pachymetry was performed using a 50-MHz ultrasound probe. Three OCT scans were obtained on preoperative and post-LASIK visits up to 6 months. An automated algorithm was developed to process the OCT images and to calculate corneal, flap, and stromal bed thickness profiles and...

- by David Huang
- •
- Algorithms, Ophthalmology, Wound Healing, Myopia

Purpose: To extend the Radiological Physics Centre (RPC) intensity-modulated radiation therapy dose verification protocol to three dimensions using optical computed tomography (CT) scans of ferrous xylenol-orange (FX) gels. Methods and Materials: The dosimetry insert in the RPC head-and-neck phantom was replaced with an FX cylindrical gel dosimeter. Two gels were calibrated, independently irradiated with 6-MV X-ray beams and scanned using laser and cone-beam (VistaÔ) optical CT, respectively. For matching dose slices, measured dose distributions were compared with Pinnacle 3 computed distributions. Results: Within high-dose regions and low gradients, doses measured using laser CT were 2% to 3% less than the computed dose, whereas with cone-beam CT they were 4% to 5% less. Inside the central 90% of the gel cylinder diameter, the fraction of voxels satisfying the two-dimensional gamma analysis (5% dose difference, 3-mm distance to agreement) with laser-beam-and cone-beam-measured dose distributions were 98.4% and 99.0%, respectively. A three-dimensional gamma analysis with cone-beam data revealed that 96.7% of voxels within the central 90% gel volume satisfied the above criteria. Within the axial and sagittal planes through the primary planning target volume (PTV), computed and measured doses using GAFChromic Ò EBT film (RPC measured) and cone-beam scanned FX gel generally agreed. At equivalent points in the planning target volumes, computed, thermoluminescent dosimeter (RPC-measured), and gel point doses agreed to within 5.1% in absolute dose. Conclusions: Laser and cone-beam CT yield comparable dose distributions in high-dose regions. The RPC head phantom and optical CT-scanned FX gels can be used for accurate intensity-modulated radiation therapy dose verification in three dimensions. Ó 2008 Elsevier Inc.

Recently, joint Spectral and Time domain Optical Coherence Tomography (joint STdOCT) has been proposed to measure ocular blood flow velocity. Limitations of CCD technology allowed only for twodimensional imaging at that time. In this paper we demonstrate fast threedimensional STdOCT based on ultrahigh speed CMOS camera. Proposed method is straightforward, fully automatic and does not require any advanced image processing techniques. Three-dimensional distributions of axial velocity components of the blood in human eye vasculature are presented: in retinal and, for the first time, in choroidal layer. Different factors that affect quality of velocity images are discussed. Additionally, the quantitative measurement allows to observe a new interesting optical phenomenon -random Doppler shift in OCT signals that forms a vascular pattern at the depth of sclera.

- by Maciej Wojtkowski and +1
- •
- Optical coherence tomography, Fourier Analysis, Automation, Lasers

To evaluate the efficacy of photobiomodulation (PBM) treatment for patients with dry age-related macular degeneration (AMD). Assessments on 42 eyes with dry AMD (age related eye disease study (AREDS) 2-4) were conducted. Multiwavelength light emitting diode (LED) light comprising of yellow (590 nm), red (670 nm) and near-infrared (790 nm) bandwidths was applied to subjects' eyes for a treatment course of 3 weeks. Outcome measures were changes in best-corrected visual acuity (BCVA), contrast sensitivity (CS), drusen volume and central drusen thickness. Significant improvement in mean BCVA of 5.90 letters (p < 0.001) was seen on completion of the 3-week treatment and 5.14 letters (p < 0.001) after 3 months. Contrast sensitivity improved significantly (log unit improvement of 0.11 (p = 0.02) at 3 weeks and 3 months (log unit improvement of 0.16 (p = 0.02) at three cycles per degree. Drusen volume decreased by 0.024 mm(3) (p < 0.001) and central drusen thickness was signifi...

- by Michael Walker
- •
- Ophthalmology, Treatment Outcome, Optical coherence tomography, Medicine

Evaluate the real-life experience with ocriplasmin on vitreomacular traction (VMT) release and full-thickness macular hole (FTMH) closure in Portugal. Multicentric, retrospective study of 83 eyes of 78 patients who were treated with intravitreal ocriplasmin for VMT with and without FTMH. Primary outcomes were VMT release and FTMH closure. Secondary outcomes included visual acuity changes and structural features on spectral-domain ocular coherence tomography. VMT resolved in 47 of the 83 eyes (56.6%) and 6 of the 12 FTMH were closed (50.0%). Mean best-corrected visual acuity (BCVA) improved from 65.1 at baseline to 70.8 ETDRS letters at the end of follow-up (p < 0.0001) with a mean follow-up of 138.8 days. Improvement in BCVA was significantly better in eyes with VMT release (p = 0.021). Approximately 73% of patients had normal ellipsoid zone integrity at the end of follow-up, 87% had no neurosensorial detachment and 40% had no intra- or subretinal fluid. VMT release and FTMH clos...

- by Manuel Domingues and +1
- •
- Treatment Outcome, Optical coherence tomography, Ophthalmic, Visual acuity

We report on a high-speed, high-efficiency, high-duty-cycle, path-length-maintaining and linear beam scanner suitable for en face scanning optical coherence microscopy. Fast transverse beam scanning is achieved by use of a double-reflection polygon mirror (DRPM) rotating at a constant speed. With a motor speed of 18,000 rpm and a scanner diameter of 50 mm, the DRPM provides a line rate up to 3 kHz, ±1.8°scanning range, and 90% duty cycle. A much higher scanning speed and much larger scanning range can be readily achieved by increasing the scanner diameter.

- by Nanguang Chen
- •
- Quantum Physics, Microscopy, Optical coherence tomography, Optical physics

To identify the incidence of and risk factors for intraocular pressure (IOP) elevation after Descemet stripping automated endothelial keratoplasty (DSAEK). Methods: Retrospective review was conducted of 68 consecutive DSAEK procedures alone, or in combination with phacoemulsification with intraocular lens implantation or exchange, performed by two surgeons at the University of Texas Southwestern Medical Center between 2005 and 2009. Eyes that developed IOP elevation above 21 mm Hg after DSAEK and requiring initiation or escalation of glaucoma therapy were evaluated. Results: Thirty-seven (54%) eyes showed IOP elevation responsive to medical treatment by a mean follow-up of 11.38 Ϯ 7.81 months. Six (8.8%) eyes required glaucoma surgery. In the eyes, which developed elevated IOP, gonioscopy did not reveal any new peripheral anterior synechiae formation. Prolonged topical steroid usage, rebubbling, combined DSAEK/cataract surgery, or repeat DSAEK were not significant factors (PϾ0.05) for development of elevated IOP, but history of previous glaucoma or ocular hypertension (OHTN) was significant (Pϭ0.007). Conclusions: Intraocular pressure elevation is not uncommon in eyes after DSAEK, but most cases can be controlled with conservative management. Intraocular pressure elevation post-DSAEK occurred by mechanisms other than peripheral anterior synechial angle closure. The only significant risk factor for development of elevated IOP in our series was a previous history of glaucoma or OHTN.

- by Meredith Allen
- •
- Optical coherence tomography, Intraocular Pressure, Follow-up studies, Incidence

for the Age-related Eye Disease Study 2 Ancillary Spectral Domain Optical Coherence Tomography Study Group* Purpose: Drusen and migrating retinal pigment epithelium have been associated with hyperreflective foci (HF) detected by spectral-domain optical coherence tomography (SD-OCT). This study sought to quantify the change in intraretinal HF distribution and its correlation with age-related macular degeneration (AMD) disease progression.

Objective: To report the 2-year outcomes of the BOLT study, a prospective randomized controlled trial evaluating intravitreous bevacizumab and modified Early Treatment Diabetic Retinopathy Study (ETDRS) macular laser therapy (MLT) in... more

- by Andrew Kaines
- •
- Archives, Treatment Outcome, Optical coherence tomography, Visual acuity

Evidence suggests that vascular abnormalities play a role in the pathogenesis of open-angle glaucoma (OAG) in some patients. This study aims to assess changes in retrobulbar and retinal blood flow over time in patients with glaucoma and examine their relationship to glaucomatous progression, as determined by retinal and optic nerve structure. In this observational study, 103 patients with OAG were examined at baseline and 18 months follow-up. Retrobulbar blood flow was measured by colour Doppler imaging in the ophthalmic, central retinal and temporal posterior ciliary artery (TPCA) and nasal short posterior ciliary artery. Retinal capillary blood flow was measured by confocal scanning laser Doppler. Peripapillary retinal nerve fibre layer thickness was assessed by optical coherence tomography. Non-parametric Wilcoxon signed ranks tests were used to assess for any statistically significant changes between the baseline and 18-month visits for the retrobulbar and retinal flow, as well ...

- by Rehan Hussain and +1
- •
- Optical coherence tomography, Clinical Sciences, Aged, Optometry and Ophthalmology

Purpose: Although usually self-limiting, central serous chorioretinopathy (CSCR) may recur or adopt a chronic course, with permanent impairment of visual acuity. Previously suggested treatments for nonresolving or recurrent CSCR have included invasive techniques, such as laser photocoagulation and intravitreal triamcinolone. We evaluated the evidence for epinephrine in the pathophysiology of CSCR and the role beta-blockade may play in treating this condition.

- by andrew tatham
- •
- Treatment Outcome, Optical coherence tomography, Visual acuity, Recurrence

To characterize the prevalence and features of subclinical foveal hypoplasia detected by optical coherence tomography (OCT) in children. Fast macular OCT scans were performed on normal children with normal vision for the development of a normative OCT-3 database; from this data, eyes with no discernable foveal depression were identified. When possible, the ocular imaging was repeated 3 years later using both OCT-3 and spectral domain OCT (SD-OCT). SD-OCT results were compared to age-matched controls. Of the 286 normal children (mean age, 8.6 ± 3.1 years) scanned, 9 (mean age, 8 ± 2.9 years; 6 males) were found to have bilateral shallow foveal depression on OCT-3 imaging, including 8 of 154 white children (5.4%) and 1 child of mixed ethnicity (white/black). Children with shallow foveas (n = 9) had larger average foveal thickness (FT) compared to the cohort of controls (n = 277) with a defined fovea (FT = 231.4 ± 8.8 vs 188.8 ± 25.0, resp. [P < 0.0001]). Mean macular volume did not...

- by Mays D
- •
- Optical coherence tomography, Visual acuity, Child, North Carolina

Optical coherence tomography (OCT) is the 'new kid on the block' in coronary imaging. This technology offers clinicians a high resolution (approximately 15 μm), that is ten times higher than the currently accepted gold standard of intravascular ultrasound and has emerged as the ideal imaging tool for the assessment of superficial components of coronary plaques and stent struts. Novel OCT systems can perform quick and safe scanning of coronary arteries with a non-occlusive technique. A brief summary containing the key physical principles of OCT technology with particular attention to the novel Fourier domain system is presented. This review will focus on clinical and research applications of OCT in interventional cardiology. The two main fields of OCT in vivo: coronary atherosclerosis assessment and the study of vessel wall response to stent implantation in terms of strut coverage and apposition will be delineated. Limitations and future perspectives of the technique are pres...

- by Giuseppe Ferrante
- •
- Cardiology, Treatment Outcome, Optical coherence tomography, Stents

To demonstrate two novel ophthalmic imaging techniques based on fast Spectral Optical Coherence Tomography (SOCT). Prospective observation case report. Research laboratory. A normal human subject. Correlation of an optical coherence retinal tomogram with known retinal anatomy, reduction of eye exposure to the probing light beam during Optical Coherence Tomography (OCT) examination. High resolution (3- x 20-microm) cross-sectional 2-dimensional images of the human retina in vivo have been obtained with only 0.1-second total illumination time (for 1024 A-scans), and approximately 200- microW eye exposure. Details of the optic disk in vivo have been visualized at a rate of eight frames per second, which is sufficient to provide real time analysis. The 3-dimensional images of the optic nerve correspond to the images obtained from a fundus camera. Because of its short acquisition time and high sensitivity, SOCT uses a 100 times lower exposure/A-scan to obtain images of comparable quality...