In the eye, ultraviolet radiation (UVR) is not known to contribute to visual perception but to mainly damage multiple structures. UVR carries higher energy than visible light and high dose exposure to UVR causes direct cellular damage, which has an important role in the development of cancer. This review provides an overview on the most recent knowledge on the role of UVR in oxidative stress (OS) in relation to noncancer ocular pathologies: various corneal pathologies, cataract, glaucoma and age-related macular degeneration. Possible OS signaling streams and mechanisms in the aging eye are discussed. Excessive exposure to UVR through live may seriously contribute to increase in OS of various eye tissues and thus lead to the advancement of serious ocular pathologies. Children are especially vulnerable to UVR because of their larger pupils and more transparent ocular media: up to 80% of a person's lifetime exposure to UVR is reached before the age of 18. Therefore, efficient everyday protection of the sensitive tissues of the eye by wearing of sunglasses, clear UVR-blocking spectacles or contact lenses should be considered from early age on. Many initiatives are taken worldwide to inform and raise the population's awareness about these possible UVR hazards to the eye.

Ocular UV doses accumulate all-day, not only during periods of direct sun exposure. The UV protection efficiency of three clear lenses was evaluated experimentally, validated by simulation, and compared to non-UV protection: a first spectacle lens with a tailored UV absorber, a second spectacle lens, minimizing UV back reflections, as well as a third spectacle lens, combining both. A tailored UV-absorber efficiently reduced overall UV irradiance to 7 %, whereas reduction of back-reflections still left UV irradiance at 42 %. Thus, clear lenses with a tailored UV absorber efficiently protect the eye from UV, supplementing sun glasses wear to an all-day protection scenario.

The role of ultraviolet radiation in oxidative stress‐related ocular pathologies is less known than its role in skin cancer. Excessive exposure to ultraviolet radiation is associated with increased oxidative stress in eye tissues, which may promote the development of photokeratitis, cataract, and retinal damages. Children are especially vulnerable: large pupils, transparent ocular media. Efficient everyday protection of the eye should be considered from early age. (Image: with permission from Carl Zeiss Vision International GmbH, Aalen, Germany)Further details can be found in the article by Iliya V. Ivanov, Timo Mappes, Patrick Schaupp, et al. (e201700377). image

Model organisms such as zebrafish play an important role for developmental biologists and experimental geneticists. Still, as they grow into their post-embryonic stage of development it becomes more and more difficult to image them because of high light scattering inside biological tissue. Optoacoustic mesoscopy based on spherically focused, high frequency, ultrasound detectors offers an alternative, where it relies on the focusing capabilities of the ultrasound detectors in generating the image rather than on the focusing of light. Nonetheless, because of the limited numerical aperture the resolution is not isotropic, and many structures, especially elongated ones, such as blood vessels and other organs, are either invisible, or not clearly identifiable on the final image. Herein, based on high frequency ultrasound detectors at 100 MHz and 50 MHz we introduce multi orientation (view) optoacoustic mesoscopy. We collect a rich amount of signals from multiple directions and combine them using a weighted sum in the Fourier domain and a Wiener deconvolution into a single high resolution three-dimensional image. The new system achieves isotropic resolutions on the order of 10 μm in-plane, 40 μm axially, and SNR enhancement of 15 dB compared to the single orientation case. To showcase the system we imaged a juvenile zebrafish ex vivo, which is too large to image using optical microscopic techniques, the reconstructed images show unprecedented performance in terms of SNR, resolution, and clarity of the observed structures. Using the system we see the inner organs of the zebrafish, the pigmentation, and the vessels with unprecedented clarity.

Whole-body optical imaging of post-embryonic stage model organisms is a challenging and long sought-after goal. It requires a combination of high-resolution performance and high-penetration depth. Optoacoustic (photoacoustic) mesoscopy holds great promise, as it penetrates deeper than optical and optoacoustic microscopy while providing high-spatial resolution. However, optoacoustic mesoscopic techniques only offer partial visibility of oriented structures, such as blood vessels, due to a limited angular detection aperture or the use of ultrasound frequencies that yield insufficient resolution. We introduce 360° multi orientation (multi-projection) raster scan optoacoustic mesoscopy (MORSOM) based on detecting an ultra-wide frequency bandwidth (up to 160 MHz) and weighted deconvolution to synthetically enlarge the angular aperture. We report unprecedented isotropic in-plane resolution at the 9–17 μm range and improved signal to noise ratio in phantoms and opaque 21-day-old Zebrafish. We find that MORSOM performance defines a new operational specification for optoacoustic mesoscopy of adult organisms, with possible applications in the developmental biology of adulthood and aging. An optoacoustic technique has been used to realize whole-body imaging of post-embryonic zebrafish by researchers in Germany and France. The whole-body imaging of biological specimens beyond the embryonic stage is highly desired for biological studies. While showing promise, raster-scan optoacoustic mesoscopy (RSOM) is limited by the low numerical aperture of the ultrasonic detectors used. Now, Murad Omar at the Technical University of Munich and co-workers have demonstrated a Multi Orientation RSOM technique that, similar to X-ray computed tomography, collects projections over 360 degrees. As it uses broad-field illumination and its resolution is limited only by ultrasound diffraction, the new method can achieve a high resolution and wide range of spatial frequencies. The team demonstrated it by obtaining high-resolution whole-body images of 21-day-old zebrafish, which cannot be obtained by optical microscopy or conventional optoacoustic mesoscopy.

Imaging depth is one of the most prominent limitations in light microscopy. The depth in which we are still able to resolve biological structures is limited by the scattering of light within the sample. We have developed an algorithm to compensate for the influence of scattering. The potential of algorithm is demonstrated on a 3D image stack of a zebrafish embryo captured with a selective plane illumination microscope (SPIM). With our algorithm we were able shift the point in depth, where scattering starts to blur the imaging and effect the image quality by around 30 µm. For the reconstruction the algorithm only uses information from within the image stack. Therefore the algorithm can be applied on the image data from every SPIM system without further hardware adaption. Also there is no need for multiple scans from different views to perform the reconstruction. The underlying model estimates the recorded image as a convolution between the distribution of fluorophores and a point spread function, which describes the blur due to scattering. Our algorithm performs a space-variant blind deconvolution on the image. To account for the increasing amount of scattering in deeper tissue, we introduce a new regularizer which models the increasing width of the point spread function in order to improve the image quality in the depth of the sample. Since the assumptions the algorithm is based on are not limited to SPIM images the algorithm should also be able to work on other imaging techniques which provide a 3D image volume.

Scattering within biological samples limits the imaging depth and the resolution in microscopy. We present a prior and regularization approach for blind deconvolution algorithms to correct the influence of scattering to increase the imaging depth and resolution. The effect of the prior is demonstrated on a three-dimensional image stack of a zebrafish embryo captured with a selective plane illumination microscope. Blind deconvolution algorithms model the recorded image as a convolution between the distribution of fluorophores and a point spread function (PSF). Our prior uses image information from adjacent z-planes to estimate the unknown blur in tissue. The increased size of the PSF due to the cascading effect of scattering in deeper tissue is accounted for by a depth adaptive regularizer model. In a zebrafish sample, we were able to extend the point in depth, where scattering has a significant effect on the image quality by around 30???m.

Intravital imaging of large specimens is intrinsically challenging for postembryonic studies. Selective plane illumination microscopy (SPIM) has been introduced to volumetrically visualize organisms used in developmental biology and experimental genetics. Ideally suited for imaging transparent samples, SPIM can offer high frame rate imaging with optical microscopy resolutions and low phototoxicity. However, its performance quickly deteriorates when applied to opaque tissues. To overcome this limitation, SPIM optics were merged with optical and optoacoustic (photoacoustic) readouts. The performance of this hybrid imaging system was characterized using various phantoms and by imaging a highly scattering ex vivo juvenile zebrafish. The results revealed the system's enhanced capability over that of conventional SPIM for high-resolution imaging over extended depths of scattering content. The approach described here may enable future visualization of organisms throughout their entire development, encompassing regimes in which the tissue may become opaque.

We report on the fabrication of polymeric whispering-gallery mode (WGM) lasers. Our approach enables high packing density by vertical stacking and multiplexed readout of resonators and lends itself to signal referencing or multi-target sensing.

We present an all-polymer photonic sensing platform based on whispering-gallery mode microgoblet lasers integrated into a microfluidic chip. The chip is entirely made from polymers, enabling the use of the devices as low-cost disposables. The microgoblet cavities feature quality factors exceeding 10(5) and are fabricated from poly(methyl methacrylate) (PMMA) using spin-coating, mask-based optical lithography, wet chemical etching, and thermal reflow. In contrast to silica-based microtoroid resonators, this approach replaces technically demanding vacuum-based dry etching and serial laser-based reflow techniques by solution-based processing and parallel thermal reflow. This enables scaling to large-area substrates, and hence significantly reduces device costs. Moreover, the resonators can be fabricated on arbitrary substrate materials, e.g., on transparent and flexible polymer foils. Doping the microgoblets with the organic dye pyrromethene 597 transforms the passive resonators into lasers. Devices have lasing thresholds below 0.6 nJ per pulse and can be efficiently pumped via free-space optics using a compact and low-cost green laser diode. We demonstrate that arrays of microgoblet lasers can be readily integrated into a state-of-the-art microfluidic chip replicated via injection moulding. In a proof-of-principle experiment, we show the viability of the lab-on-a-chip via refractometric sensing, demonstrating a bulk refractive index sensitivity (BRIS) of 10.56 nm per refractive index unit.

We report on efficient free-space read-out of whispering-gallery mode microlasers using circular micromirrors. A ten-fold improvement in detection efficiency can be achieved by directing emission from all azimuthal angles of the cavity to the detector.

We present our latest results on microgoblet lasers as biosensors. Surface functionalization is performed with high resolution and throughput by aligned microcontact stamping. We show simultaneous device readout, the resulting cross-referencing capabilities and functionalization reconfiguration.

Microgoblet laser pairs are presented for cross‐referenced on‐chip biomolecular sensing. Parallel readout of the microlasers facilitates effective mutual filtering of highly localized refractive index and temperature fluctuations in the analyte. Cross‐referenced detection of two different types of proteins and complete chemical transducer reconfiguration is demonstrated. Selective surface functionalization of the individual lasers with high spatial accuracy is achieved by aligned microcontact stamping.

In article 1500066, U. Bog, M. Hirtz, and co‐workers demonstrate on‐chip biomolecular sensing using whispering‐gallery‐mode microgoblet lasers. Biomolecular detection is usually affected by signal disturbances, induced by refractive index and temperature fluctuations inside the liquid analyte. The densely packed laser pairs enable mutual and localized filtering of such signal disturbances. The sensor functionalization is performed by aligned microcontact stamping, resulting in a highly localized, cross‐contamination‐free treatment of the individual microlasers.

NEMO is the European "Network of Excellence on Micro-Optics". One of the objectives is to disseminate knowledge on micro-optics. Therefore NEMO plans to inform pupils about the crucial role of micro-optics This is done through the distribution of an educational kit to their physics/technology teachers. This kit has been realized through a cooperative action of different partners of the NEMO-network all over Europe. It contains a variety of replicated micro-optical refractive and diffractive components, and a semiconductor laser source. The kit is supplemented with a CD-ROM which explains the basic concepts and describes possible experiments and experimental setups. It contains also a computer tutorial which simulates the optical processes of image formation. It is hoped that this will encourage interest in optics and, more generally, in science as an area of future study and as a possible career choice. At the conference the realization and the lay out of the EduKit will be commented and a demonstration will be given.

Lasing from whispering-gallery mode (WGM) resonators occurs omnidirectional in azimuthal plane. Most applications of WGM resonators require spectral analysis with off-chip detectors, where in-plane emission and beam divergence hinder efficient detection. We demonstrate redirecting WGM laser emission from all azimuthal angles using a circular micromirror placed around the cavity. By collecting reflections off the micromirror via free-space optics, read-out intensity improved by one order of magnitude. Blocking vertically emitted spontaneous emission and recording reflections off the micromirror only, signal-to-noise ratio improved from 4.6 dB to 15 dB. Our read-out concept may be applied to arbitrary WGM cavity geometries without deteriorating the cavity's quality factor.

A novel surface functionalization technique is presented for large-scale selective molecule deposition onto whispering gallery mode microgoblet cavities. The parallel technique allows damage-free individual functionalization of the cavities, arranged on-chip in densely packaged arrays. As the stamp pad a glass slide is utilized, bearing phospholipids with different functional head groups. Coated microcavities are characterized and demonstrated as biosensors.

We report on whispering gallery mode (WGM) resonators consisting of poly(methyl methacrylate) (PMMA) which are promising candidates for label-free biosensing applications. The optical modes in these resonators experience a wavelength shift when the refractive index of the surrounding medium changes or when molecules attach to the resonator. Different methods can be used for functionalization of the resonator surface to obtain sensors which are sensitive to specific molecules. To obtain higher sensitivities coupled resonators can be produced. If the resonators are close enough the modes of the single cavities couple and supermodes extending over both cavities develop. Analogously to the hydrogen molecule a bonding and an anti-bonding optical mode is observed. The bonding mode shows a field enhancement in the gap which results in a stronger interaction of the mode with the surrounding medium.