Ultrafast lasers have a crucial function in many fields of science; however, up to now, high-energy pulses directly from compact, efficient and low-power semiconductor lasers are not available. Therefore, we introduce a new approach based on temporal compression of the continuous-wave, wavelength-swept output of Fourier domain mode-locked lasers, where a narrowband optical filter is tuned synchronously to the round-trip time of light in a kilometre-long laser cavity. So far, these rapidly swept lasers enabled orders-of-magnitude speed increase in optical coherence tomography. Here we report on the generation of ~60-70 ps pulses at 390 kHz repetition rate. As energy is stored ...

Gradient Refractive INdex (GRIN) optical components have historically fallen short of theoretical expectations. A recent breakthrough is the manufacturing of nanolayered spherical GRIN (S-GRIN) polymer optical elements, where the construction method yields refractive index gradients that exceed 0.08. Here we report on the application of optical coherence tomography (OCT), including micron-class axial and lateral resolution advances, as effective, innovative methods for performing nondestructive diagnostic metrology on S-GRIN. We show that OCT can be used to visualize and quantify characteristics of the material throughout the manufacturing process. Specifically, internal film structure may be revealed and data are processed to extract ...

High-resolution real-time tomography of scattering tissues is important for many areas of medicine and biology 1 , 2 , 3 , 4 , 5 , 6 . However, the compromise between transverse resolution and depth-of-field, in addition to low sensitivity deep in tissue, continues to impede progress towards cellular-level volumetric tomography. Computed imaging has the potential to solve these long-standing limitations. Interferometric synthetic aperture microscopy 7 , 8 , 9 is a computed imaging technique enabling high-resolution volumetric tomography with spatially invariant resolution. However, its potential for clinical diagnostics remains largely untapped because full volume reconstructions required lengthy post-processing, and the phase-stability requirements have been difficult to satisfy ...

Quantum information science promises transformative impact over a range of key technologies in computing, communication, and sensing. A prominent example uses entangled photons to overcome the resolution-degrading effects of dispersion in the medical-imaging technology, optical coherence tomography. The quantum solution introduces new challenges: inherently low signal and artifacts, additional unwanted signal features. It has recently been shown that entanglement is not a requirement for automatic dispersion cancellation. Such classical techniques could solve the low-signal problem, however they all still suffer from artifacts. Here, we introduce a method of chirped-pulse interferometry based on shaped laser pulses, and use it to produce ...

Spectral-Domain Optical Coherence Tomography (SD-OCT) is an optical method capable of 3D imaging of object's internal structure with micron-scale resolution. Modern SD-OCT tools offer the speed capable of online monitoring of printed devices. This paper demonstrates the use of SD-OCT in a simulated roll-to-roll (R2R) process through monitoring some structural properties of moving screen printed interdigitated electrodes. It is shown that structural properties can be resolved for speeds up to ca. 1 m/min, which is the first step towards application of this method in real manufacturing processes, including roll-to-roll (R2R) printing.

Purpose The aim of this study is to compare the therapeutic effect of a single intravitreal bevacizumab (IVB) injection in eyes with diabetic macular oedema (DMO) of different patterns determined by optical coherence tomography (OCT). Methods Medical records of patients who had a single IVB injection for DMO were analysed retrospectively. Eyes with a clinically significant DMO and a central foveal thickness (CFT) of 250   μ m or more determined by OCT were included in the analysis. Best-corrected visual acuity (BCVA), CFT and total macular volume values before and after the injection were recorded. Eyes were divided into sponge-like diffuse retinal ...

Purpose To determine macular thickness changes after uncomplicated cataract surgery using spectral domain optical coherence tomography (OCT). Methods This was a prospective non-randomized, clinical study. Data were analysed for 40 healthy patients undergoing uneventful phacoemulsification. OCT measurements were performed before surgery and postoperatively at day 1, week 1 and 2, and month 1, 2, 3, and 6. The retinal map was divided into central point thickness (CPT), central 1-mm subfield (CSF), and two peripheral ring areas with diameters of 3 and 6   mm. Fellow eyes were used as controls. Retinal thickness change between the operated and fellow eyes were compared ...

Purpose To demonstrate axonal loss in the retinal nerve fiber layer (RNFL) of patients with Parkinson’s disease (PD) and to evaluate the ability of Fourier-domain optical coherence tomography (OCT) to detect RNFL degeneration and retinal thinning in these patients. Methods PD patients (n = 100) and healthy subjects (n = 100) were included in the study and underwent visual acuity, color vision, and OCT examinations using two next-generation Fourier-domain devices (Spectralis and Cirrus). Differences in the RNFL thicknesses were compared between patients and controls. Results RNFL thicknesses were significantly reduced in PD patients compared with healthy subjects, especially those obtained using ...

This paper describes a novel optical method for label-free quantitative imaging of cerebral blood flow (CBF) and intracellular motility (IM) in the rodent cerebral cortex. This method is based on a technique that integrates dynamic light scattering (DLS) and optical coherence tomography (OCT), named DLS–OCT. The technique measures both the axial and transverse velocities of CBF, whereas conventional Doppler OCT measures only the axial one. In addition, the technique produces a three-dimensional map of the diffusion coefficient quantifying nontranslational motions. In the DLS–OCT diffusion map, we observed high-diffusion spots, whose locations highly correspond to neuronal cell bodies and ...

Here we introduce tethered capsule endomicroscopy, which involves swallowing an optomechanically engineered pill that captures cross-sectional microscopic images of the gut wall at 30 μm (lateral) × 7 μm (axial) resolution as it travels through the digestive tract. Results in human subjects show that this technique rapidly provides three-dimensional, microstructural images of the upper gastrointestinal tract in a simple and painless procedure, opening up new opportunities for screening for internal diseases.

Purpose The purpose of this study was to determine the subfoveal scleral thickness in highly myopic eyes by enhanced depth imaging spectral-domain optical coherence tomography (EDI-OCT) and to identify the ocular parameters significantly associated with the scleral thickness. Methods The subfoveal scleral thickness of myopic eyes (≥−8 diopters (D) or axial length ≥26.5   mm) was examined by EDI-OCT. The correlations between the thickness and the best-corrected visual acuity (BCVA), refractive error, axial length (AL), the subfoveal retinal thickness, choroidal thickness, and posterior staphyloma height 2   mm from the fovea were investigated. Results A total of 75 eyes of 54 ...

The most common intraocular vascular tumours are choroidal haemangiomas, vasoproliferative tumours, and retinal haemangioblastomas. Rarer conditions include cavernous retinal angioma and arteriovenous malformations. Options for ablating the tumour include photodynamic therapy, argon laser photocoagulation, trans-scleral diathermy, cryotherapy, anti-angiogenic agents, plaque radiotherapy, and proton beam radiotherapy. Secondary effects are common and include retinal exudates, macular oedema, epiretinal membranes, retinal fibrosis, as well as serous and tractional retinal detachment, which are treated using standard methods (ie, intravitreal anti-angiogenic agents or steroids as well as vitreoretinal procedures, such as epiretinal membrane peeling and release of retinal traction). The detection, diagnosis, and monitoring of ...

Non-invasive optical imaging techniques, such as optical coherence tomography 1 , 2 , 3 , are essential diagnostic tools in many disciplines, from the life sciences to nanotechnology. However, present methods are not able to image through opaque layers that scatter all the incident light 4 , 5 . Even a very thin layer of a scattering material can appear opaque and hide any objects behind it 6 . Although great progress has been made recently with methods such as ghost imaging 7 , 8 and wavefront shaping 9 , 10 , 11 , present procedures are still invasive because they require either a detector 12 or a nonlinear material ...

Purpose To determine normative values and associations of retinal nerve fiber layer (RNFL) and optic disc parameters in normal eyes measured by spectral domain optical coherence tomography (OCT). Methods In a population-based setting, 1521 young adults were examined as part of the Sydney Adolescent Vascular and Eye Study (SAVES). Their mean age was 17.3±0.6 years. RNFL and optic disc parameter measurements were made using Cirrus HD-OCT 4000. Results The average RNFL was found to be 99.4±9.6   μ m. RNFL thickness was least for the temporal quadrant (69.9±11.2   μ m), followed by the nasal ...

Purpose The objective of this study is to assess whether baseline optic nerve head (ONH) topography and retinal nerve fiber layer thickness (RNFLT) are predictive of glaucomatous visual-field progression in glaucoma suspect (GS) and glaucomatous eyes, and to calculate the level of risk associated with each of these parameters. Methods Participants with ≥28 months of follow-up were recruited from the longitudinal Advanced Imaging for Glaucoma Study. All eyes underwent standard automated perimetry (SAP), confocal scanning laser ophthalmoscopy (CSLO), time-domain optical coherence tomography (TDOCT), and scanning laser polarimetry using enhanced corneal compensation (SLPECC) every 6 months. Visual-field progression was assessed using ...

For swept source optical coherence tomography and high-speed transient spectroscopy, micro-electromechanical-systems-based vertical-cavity surface-emitting lasers (MEMS-VCSELs) are an appealing optical source owing to their narrow linewidth, continuous single-mode tuning and high-speed tunability. In particular, a wide tuning range (>100 nm) near 1,310 nm would be extremely

Closer collaboration between physicists, engineers and biologists is vital for the future success of biophotonics. Barriers between the communities of photonics and biology must be bridged more effectively if the discipline of biophotonics is to fulfil its true potential. Historically, the two communities have tended to work in isolation, speaking different scientific languages, publishing in different journals, attending different conferences and working in different departments. The good news is that this behaviour seems to be changing, and that increased collaboration and mixing between those working in the life sciences and the physical sciences is likely if sufficient efforts are made ...

Purpose To investigate serial changes of the Ahmed glaucoma valve (AGV) implant tube in the anterior chamber by anterior segment optical coherence tomography (AS-OCT). Methods Patients who had received AGV implantation without complications (n=48) were included in this study. Each patient received follow-up examinations including AS-OCT at days 1 and 2, week 1, and months 1, 3, 6, and 12. Tube parameters were defined to measure its length and position. The intracameral length of the tube was from the tip of the bevel-edged tube to the sclerolimbal junction. The distance between the extremity of the tube and the anterior ...

Purpose To study the change in retinal nerve fibre layer (RNFL) thickness and optic nerve head (ONH) parameters using optical coherence tomography (Stratus OCT 3) after trabeculectomy in adult patients with glaucoma. Methods A total of 17 patients with glaucoma undergoing trabeculectomy were recruited. Average and quadrant RNFL thickness measurements, vertical integrated rim area, horizontal integrated rim width, disc area, cup area, and rim area were measured using Stratus OCT within a week before surgery and at 1 week, 1 and 3 months postoperatively. Main outcome measures were change in RNFL and ONH parameters. Pre- and postoperative values were analysed ...

Optical coherence tomography (OCT) is a high-resolution light-based technique widely used in ophthalmology to image the retina in real time. Researchers in The Netherlands have transferred this technique to the human kidney, and now they report the first in vivo study of OCT for renal tumours in BJU International

Aims To examine the rate of macular thickness loss using time-domain optical coherence tomography (OCT) in functionally progressing versus non-progressing eyes, determined by standard automated perimetry (SAP). Methods Glaucoma suspects (GS) and glaucomatous (G) eyes underwent SAP and OCT imaging every 6 months. Functional progression was determined using pointwise linear regression, defined as 2 contiguous locations losing ≥1.0 dB/year at P<1.0% in the same hemifield. The annual rate of macular thickness loss was calculated from inner and outer regions of the macular map. Results 72 eyes (43 GS and 29G) with ≥30 months of follow-up were enroled. Fourteen eyes demonstrated SAP progression. The annual rate of macular thickness loss (μm/year) in progressing eyes was faster (all P<0.05) than non-progressing eyes in temporal outer (−1.90±2.97 vs 0.33±2.77), nasal inner (−1.70±2.66 vs 0.14±2.76), superior inner (−2.15±4.57 vs 0.51±2.99), temporal inner quadrants (−2.58±5.05 vs −0.38±2.34), and the average of inner macular quadrants (−1.84±2.90 vs 0.03±2.10). The rate of loss in the nasal inner (P=0.02) and temporal outer (P=0.02) macular regions was associated with optic disc haemorrhage. Conclusions Eyes with SAP progression have significantly greater rates of macular thickness loss consistent with glaucomatous retinal ganglion cell atrophy, as compared with non-progressing eyes.

Purpose To evaluate changes in macular morphology due to myopic choroidal neovascularization (CNV), using spectral-domain optical coherence tomography (SD-OCT). Methods In all, 22 eyes with recent-onset untreated CNV underwent 1 intravitreal injection of anti-vascular endothelial growth factor (anti-VEGF), followed by a pro-re-nata regimen. SD-OCT was performed at baseline (before first administration of anti-VEGF treatment) and month 1, and 2; macular morphologic changes and outer retina characteristics (SD-OCT findings) associated with CNV activity were evaluated. Sensitivity and specificity were calculated for SD-OCT findings using fluorescein angiography (FA) as standard reference. Results Mean central retinal thickness (CRT) showed no significant reduction from ...

The past decade has seen dramatic technological advances in the field of optical coherence tomography (OCT) imaging. These advances have driven commercialization and clinical adoption in ophthalmology, cardiology and gastrointestinal cancer screening. Recently, an array of OCT-based imaging tools that have been developed for preclinical intravital cancer imaging applications has yielded exciting new capabilities to probe and to monitor cancer progression and response in vivo. Here, we review these results, forecast the future of OCT for preclinical cancer imaging and discuss its exciting potential to translate to the clinic as a tool for monitoring cancer therapy.

Multiple sclerosis (MS) is a common neurological disease in North America and Europe. Although most patients develop major locomotor disability over the course of 15–20 years, in approximately one-third of patients the long-term course is favorable, with minimal disability. Although current disease-modifying treatments reduce the relapse rate, their long-term effects are uncertain. MS treatment trials are challenging because of the variable clinical course and typically slow evolution of the disease. Magnetic resonance imaging (MRI) is sensitive in monitoring MS pathology and facilitates evaluation of potential new treatments. MRI measurements of lesion activity have identified new immunomodulatory treatments for preventing ...