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Tabuchi H, Yamauchi T, Shojo T, Takase K, Tanabe M. Training data size and predication errors in the use of machine-learning assisted intraocular lens power calculation. Sci Rep 2023; 13:11348. [PMID: 37443278 PMCID: PMC10344910 DOI: 10.1038/s41598-023-38616-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 07/11/2023] [Indexed: 07/15/2023] Open
Abstract
This retrospective study examined the effect of the size of training data on the accuracy of machine learning-assisted SRK/T power calculation. Clinical records of 4800 eyes of 4800 Japanese patients with intraocular lenses (IOLs) were reviewed. A support vector regressor (SVR) was used for refining the SRK/T formula, and dataset sizes for training and evaluation were reduced from full to 1/64. The prediction errors from the postoperative refractions were calculated, and the proportion within ± 0.25 D, ± 0.50 D, and ± 1.00 D of errors were compared with those using full data. The influence of the difference in A-constant was also evaluated. Prediction errors within ± 0.50 D in the use of full data were obtained with the dataset of ≥ 150 eyes (P = 0.016), whereas the datasets of ≥ 300 eyes were required for the error within ± 0.25 D (P < 0.030). The prediction errors did not alter with the A-constant values among IOLs with open-loop haptics, except for IOLs with plated haptics. In conclusion, the accuracy of SVR-assisted SRK/T could be achieved with the training dataset of ≥ 150 eyes for the Japanese population, and the calculation was versatile for any open-looped IOLs.
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Park S, Jo Y, Kang M, Hong JH, Ko S, Kim S, Park S, Park HC, Shim SH, Choi W. Label-free adaptive optics single-molecule localization microscopy for whole zebrafish. Nat Commun 2023; 14:4185. [PMID: 37443177 PMCID: PMC10344925 DOI: 10.1038/s41467-023-39896-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 06/30/2023] [Indexed: 07/15/2023] Open
Abstract
Specimen-induced aberration has been a major factor limiting the imaging depth of single-molecule localization microscopy (SMLM). Here, we report the application of label-free wavefront sensing adaptive optics to SMLM for deep-tissue super-resolution imaging. The proposed system measures complex tissue aberrations from intrinsic reflectance rather than fluorescence emission and physically corrects the wavefront distortion more than three-fold stronger than the previous limit. This enables us to resolve sub-diffraction morphologies of cilia and oligodendrocytes in whole zebrafish as well as dendritic spines in thick mouse brain tissues at the depth of up to 102 μm with localization number enhancement by up to 37 times and localization precision comparable to aberration-free samples. The proposed approach can expand the application range of SMLM to whole zebrafish that cause the loss of localization number owing to severe tissue aberrations.
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Duncan JL, Carroll J. Adaptive Optics Imaging of Inherited Retinal Disease. Cold Spring Harb Perspect Med 2023; 13:a041285. [PMID: 36220331 PMCID: PMC10317068 DOI: 10.1101/cshperspect.a041285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The human retina is amenable to direct, noninvasive visualization using a wide array of imaging modalities. In the ∼140 years since the publication of the first image of the living human retina, there has been a continued evolution of retinal imaging technology. Advances in image acquisition and processing speed now allow real-time visualization of retinal structure, which has revolutionized the diagnosis and management of eye disease. Enormous advances have come in image resolution, with adaptive optics (AO)-based systems capable of imaging the retina with single-cell resolution. In addition, newer functional imaging techniques provide the ability to assess function with exquisite spatial and temporal resolution. These imaging advances have had an especially profound impact on the field of inherited retinal disease research. Here we will review some of the advances and applications of AO retinal imaging in patients with inherited retinal disease.
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Vasquez B, Campos B, Cao A, Theint AT, Zeiger W. High-Sensitivity Intrinsic Optical Signal Imaging Through Flexible, Low-Cost Adaptations of an Upright Microscope. eNeuro 2023; 10:ENEURO.0046-23.2023. [PMID: 37550064 PMCID: PMC10408783 DOI: 10.1523/eneuro.0046-23.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 06/14/2023] [Accepted: 06/20/2023] [Indexed: 08/09/2023] Open
Abstract
Intrinsic optical signal imaging (IOSI) is a staple technique in modern neuroscience. Pioneered >30 years ago, IOSI allows macroscopic mapping of neuronal activity throughout the cortex. The technique has been used to study sensory processing and experience-dependent plasticity, and is often used as an adjunctive procedure to localize cortical areas for subsequent targeting by other imaging or physiology techniques. Despite the ubiquity of IOSI in neuroscience, there are few commercially available turn-key IOSI systems. As a result, investigators have typically resorted to building their own imaging systems. Over the years, simplified systems built either as dedicated rigs or incorporated into existing microscope platforms have been developed. Here we present a straightforward set of adaptations that can be applied to any standard upright microscope, using readily available, inexpensive, commercial parts for illumination, optics, and signal detection, that enables high-sensitivity IOSI. Using these adaptations, we are able to readily map sensory-evoked signals across the somatosensory and visual cortex, including single-whisker barrel cortical activity maps in mice. We show that these IOSI maps are highly reproducible across animals and can be used to study plasticity mechanisms in the somatosensory cortex. We also provide open-source applications to control illumination and analyze raw data to generate activity maps. We anticipate that these resources will be useful for neuroscience investigators looking to add IOSI capabilities to an existing microscope in the laboratory on a budget.
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Kenny PI, Kozhaya K, Truong P, Weikert MP, Wang L, Hill WE, Koch DD. Efficacy of segmented axial length and artificial intelligence approaches to intraocular lens power calculation in short eyes. J Cataract Refract Surg 2023; 49:697-703. [PMID: 36940190 DOI: 10.1097/j.jcrs.0000000000001185] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 03/14/2023] [Indexed: 03/21/2023]
Abstract
PURPOSE In short eyes, to compare the predictive accuracy of newer intraocular lens (IOL) power calculation formulas using traditional and segmented axial length (AL) measurements. SETTING Cullen Eye Institute, Baylor College of Medicine, Houston, Texas and East Valley Ophthalmology, Mesa, Arizona. DESIGN Multi-center retrospective case series. METHODS Measurements from an optical biometer were collected in eyes with AL <22 mm. IOL power calculations were performed with 15 formulas using 2 AL values: (1) machine-reported traditional AL (Td-AL) and (2) segmented AL calculated with the Cooke-modified AL nomogram (CMAL). 1 AL method and 7 formulas were selected for pairwise analysis of mean absolute error (MAE) and root mean square absolute error (RMSAE). RESULTS The study comprised 278 eyes. Compared with the Td-AL, the CMAL produced hyperopic shifts without differences in RMSAE. The ZEISS AI IOL Calculator (ZEISS AI), K6, Kane, Hill-RBF, Pearl-DGS, EVO, and Barrett Universal II (Barrett) formulas with Td-AL were compared pairwise. The ZEISS AI demonstrated smaller MAE and RMSAE than the Barrett, Pearl-DGS, and Kane. K6 had a smaller RMSAE than the Barrett formula. In 73 eyes with shallow anterior chamber depth, the ZEISS AI and Kane had a smaller RMSAE than the Barrett. CONCLUSIONS ZEISS AI outperformed Barrett, Pearl-DGS, and Kane. The K6 formula outperformed some formulas in selected parameters. Across all formulas, use of a segmented AL did not improve refractive predictions.
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Bianchi L, Bossi A, Pifferi A, Saccomandi P. Characterization of the Optical and Thermal Properties of Cardiac Tissue as a Function of Temperature. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2023; 2023:1-4. [PMID: 38083459 DOI: 10.1109/embc40787.2023.10340629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
In this work, we devised the first characterization of the optical and thermal properties of ex vivo cardiac tissue as a function of different selected temperatures, ranging from room temperature to hyperthermic and ablative temperatures. The broadband (i.e., from 650 nm to 1100 nm) estimation of the optical properties, i.e., absorption coefficient (μa) and reduced scattering coefficient $({\mu ^{\prime}}_s)$, was performed by means of time-domain diffuse optics. Besides, the measurement of the thermal properties was based on the transient hot-wire technique, employing a dual-needle probe to estimate the tissue thermal conductivity (k), thermal diffusivity (α), and volumetric heat capacity (Cv). Increasing the tissue temperature led to variations in the spectral characteristics of μa (e.g., the redshift of the 780 nm peak, the rise of a new peak at 840 nm, and the formation of a valley at 900 nm). Moreover, an increase in the values of ${\mu ^{\prime}}_s$ was assessed as tissue temperature raised (e.g., for 800 nm, at 25 °C ${\mu ^{\prime}}_s = 9.8{\text{ c}}{{\text{m}}^{{\text{ - 1}}}}$, while at 77 °C ${\mu ^{\prime}}_s = 29.1{\text{ c}}{{\text{m}}^{{\text{ - 1}}}}$). Concerning the thermal properties characterization, k was almost constant in the selected temperature interval. Conversely, α and Cv were subjected to an increase and a decrease with temperature, respectively; thus, they registered values of 0.190 mm2/s and 3.03 MJ/(m3•K) at the maximum investigated temperature (79 °C), accordingly.Clinical Relevance- The experimentally obtained optical and thermal properties of cardiac tissue are useful to improve the accuracy of simulation-based tools for thermal therapy planning. Furthermore, the measured properties can serve as a reference for the realization of tissue-mimicking phantoms for medical training and testing of medical instruments.
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Ding Y, Hou M, Liu L, Mao Y, Liu X, Wu M. Prediction of postoperative effective lens position using iris root depth in primary angle-closure diseases. J Cataract Refract Surg 2023; 49:691-696. [PMID: 36853845 DOI: 10.1097/j.jcrs.0000000000001174] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 02/16/2023] [Indexed: 03/01/2023]
Abstract
PURPOSE To evaluate the role of a new parameter, iris root depth (IRD), in intraocular lens power calculation using ultrasound biomicroscopy (UBM) in primary angle-closure diseases (PACDs), and to compare the accuracy of 6 formulas in PACDs: Barrett Universal II (BUII), Haigis, Hill-Radial Basis Function (RBF) v. 3.0, Hoffer Q, Kane and Sanders Retzlaff Kraff/Theoretical (SRK)/T. SETTING Zhongshan Ophthalmic Center, Guangzhou, China. DESIGN Retrospective consecutive case series. METHODS Patients diagnosed with PACDs who had undergone cataract surgery were reviewed to first evaluate the performance of 6 formulas. Then preoperative UBM examinations of 58 eyes were used to measure IRD and predict effective lens position (ELP) to generate the Haigis IRD formula. The accuracy of Haigis IRD was compared with BUII, Haigis and Kane formulas. The SD of predicted error was the main indicator evaluating formula performance, according to heteroscedastic analysis. RESULTS 103 eyes (103 patients) were included. The SDs of Kane (0.59, P = .01), RBF 3.0 (0.61, P = .02) and SRK/T formula (0.62, P = .04) were significantly lower than Hoffer Q. Modified with IRD, Haigis IRD generated the lowest SD (0.41), which was significantly lower than Haigis formula (0.54, P = .03) and was equal to Kane formula (0.45, P = .37). CONCLUSIONS Kane, RBF 3.0 and SRK/T were more accurate in PACD eyes. Optimized with IRD, Haigis IRD formula achieved the lowest SD and had comparable accuracy with Kane formula. IRD could be a promising parameter to improve accuracy of IOL power calculation for PACDs.
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Wang X, Zhang J, Sethian J. High precision control of laser energy for laser-matter interaction studies. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2023; 94:073003. [PMID: 37449893 DOI: 10.1063/5.0149115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 07/01/2023] [Indexed: 07/18/2023]
Abstract
Precise, highly reproducible control of the laser energy is required for high confidence laser-matter interaction research such as in dynamic compression science and high energy density physics. The energy must be adjustable without affecting the pulse shape (time varying intensity) or beam smoothness. We have developed a convenient two-stage energy tuning method for a nominal 100 J, 351 nm (UV) laser. The energy is adjusted in 10 J (10%) increments by operating the laser at full energy and inserting a beam splitter in the laser output. As the splitter is located after the final frequency tripling optics, the UV pulse shape is unchanged. The energy is varied by substituting a splitter of different reflectivity. For finer 3 J (3%) increments, the infrared pulse is attenuated inside the laser before the final amplifier. This requires modest tuning to preserve the pulse shape. The demonstrated variation in shot-to-shot reproducibility is less than +/-2.5 J (5% of the full energy), irrespective of the laser output energy. These approaches can be adapted to most ∼100 J class lasers. We describe these techniques and show two examples where they have elucidated the underlying physics in laser shock compression experiments. One used only the beam splitters to establish the pressure for melting in iron. The other combined both techniques to finely increment the peak stress (∼2 GPa steps) in germanium to precisely determine the onset and completion of melting-including the melting kinetics. These unambiguous results would not be possible without the developments described here.
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Reck J, Kleinert M, Mihov K, Kresse M, Yilmaz C, Hoffmann C, Hoffmann P, Froese V, Kertzscher U, Mykhailiuk K, Michaelis J, Weigel W, Scholand S, Heupke HJ, Weigel M, De Felipe D, Qian T, Conradi H, Zawadzki C, Keil N, Schell M. Eight-channel SiNx microring-resonator based photonic biosensor for label-free fluid analysis in the optical C-band. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2023; 2023:1-4. [PMID: 38083739 DOI: 10.1109/embc40787.2023.10340677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
A lab-on-a-chip multichannel sensing platform for biomedical analysis based on optical silicon nitride (SiNx) microring-resonators (MRR) was established. The resonators were surface functionalized and finally combined with a microfluidic chamber for validation using an avidin-biotin ligand-binding assay. The results with a limit of detection (LOD) of 2.3∙10-5 and a mean intra-assay coefficient of variation (CV) of ±10.0 %, also under consideration of FDA guidelines, show promising future applicability for a wide variety of targets in the field of outpatient medical diagnostics and life science.Clinical Relevance- Biomarkers play a crucial role in physiological processes of the human body. To enable instantaneous and decentralized analysis of these markers, systems are needed that can be used in a laboratory-independent environment with minimal amounts of biofluid. An example is the utilization of such systems for neonates or infants.
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Adane AM, Park SY. Bilayer Actuator Film for Urea Biosensing with Dual Responsiveness: Bending Actuation and Photonic Color Change. ACS Sens 2023; 8:2290-2297. [PMID: 37213078 DOI: 10.1021/acssensors.3c00296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A noninvasive sweat-based biosensor was developed for urea detection using a photonic bilayer actuator film (BAF) consisting of an interpenetrating polymer network (IPN) as the active layer and a flexible poly(ethylene terephthalate) (PET) substrate as the passive layer (IPN/PET). The active IPN layer comprises intertwined solid-state cholesteric liquid crystal and poly(acrylic acid) (PAA) networks. Urease was immobilized in the PAA network in the IPN layer of the photonic BAF. The interaction with aqueous urea altered the curvature and photonic color of the photonic urease-immobilized IPN/PET (IPNurease/PET) BAF. The curvature (and wavelength of the photonic color) of the IPNurease/PET BAF increased linearly with urea concentration (Curea) in the range of Curea = 20-65 (and 30-65) mM with a limit of detection value of 1.42 (and 1.34) mM. The developed photonic IPNurease/PET BAF exhibited high selectivity toward urea and excellent spike test results with real human sweat. This novel IPNurease/PET BAF is promising because it enables battery-free, cost-effective, and visual detection-based analysis without the use of sophisticated instruments. Furthermore, the application of this photonic IPN/PET BAF can be easily extended to other biosensors by immobilizing other receptors on the IPN.
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Nah SH, Unsihuay D, Wang P, Yang S. A Highly Sensitive and Specific Photonic Crystal-Based Opioid Sensor with Rapid Regeneration. ACS APPLIED MATERIALS & INTERFACES 2023; 15:27647-27657. [PMID: 37252783 PMCID: PMC10636717 DOI: 10.1021/acsami.3c03722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Opioid misuse and overdose have caused devastating public health challenges and economic burdens, calling for the need of rapid, accurate sensitive opioid sensors. Here, we report a photonic crystal-based opioid sensor in the total internal reflection configuration, providing label-free, rapid, quantitative measurements through change of the refractive index. The one-dimensional photonic crystal with a defect layer that is immobilized with opioid antibodies acts as a resonator with an open microcavity. The highly accessible structure responds to analytes within a minute after the aqueous opioid solution is introduced, achieving the highest sensitivity of 5688.8 nm/refractive index unit (RIU) at the incident angle of 63.03°. Our sensor shows a limit of detection (LOD) of 7 ng/mL for morphine in phosphate-buffered saline (PBS, pH 7.4) solutions, well below the required clinical detection limit, and an LOD of 6 ng/mL for fentanyl in PBS, close to the clinical requirement. The sensor can selectively detect fentanyl from a mixture of morphine and fentanyl and be regenerated in 2 min with up to 93.66% recovery rate after five cycles. The efficacy of our sensor is further validated in artificial interstitial fluid and human urine samples.
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Olsen T, Cooke DL, Findl O, Gatinel D, Koch D, Langenbucher A, Melles RB, Yeo TK. Surgeons need to know more about intraocular lens design for accurate power calculation. J Cataract Refract Surg 2023; 49:556-557. [PMID: 36753322 DOI: 10.1097/j.jcrs.0000000000001159] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 01/30/2023] [Indexed: 02/09/2023]
Abstract
Improvement in biometry and formulas has raised the bar for accurate intraocular lens (IOL) power calculation. However, when we look closely at the performance of a specific IOL model, we often find that the prediction error varies with the implant power. This phenomenon has no explanation other than that the optic design of the IOL has shifted over the power range, thereby disrupting the assumptions of the calculations. By this report, we call the industry to be more transparent and disclose the basic information about the IOL design that is important for accurate IOL power calculation. The relevant information concerns the refractive index, the central optic thickness, the anterior and posterior curvature radii, the toricity location, the spherical aberration, and haptic angulation. The goal is to predict possible shifts in principal planes or IOL position over the power range causing a refractive surprise if not corrected for.
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Parsanasab M, Hayakawa C, Spanier J, Shen Y, Venugopalan V. Analysis of relative error in perturbation Monte Carlo simulations of radiative transport. JOURNAL OF BIOMEDICAL OPTICS 2023; 28:065001. [PMID: 37293394 PMCID: PMC10245552 DOI: 10.1117/1.jbo.28.6.065001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 04/25/2023] [Accepted: 05/03/2023] [Indexed: 06/10/2023]
Abstract
Significance Perturbation and differential Monte Carlo (pMC/dMC) methods, used in conjunction with nonlinear optimization methods, have been successfully applied to solve inverse problems in diffuse optics. Application of pMC to systems over a large range of optical properties requires optimal "placement" of baseline conventional Monte Carlo (cMC) simulations to minimize the pMC variance. The inability to predict the growth in pMC solution uncertainty with perturbation size limits the application of pMC, especially for multispectral datasets where the variation of optical properties can be substantial. Aim We aim to predict the variation of pMC variance with perturbation size without explicit computation of perturbed photon weights. Our proposed method can be used to determine the range of optical properties over which pMC predictions provide sufficient accuracy. This method can be used to specify the optical properties for the reference cMC simulations that pMC utilizes to provide accurate predictions over a desired optical property range. Approach We utilize a conventional error propagation methodology to calculate changes in pMC relative error for Monte Carlo simulations. We demonstrate this methodology for spatially resolved diffuse reflectance measurements with ±20% scattering perturbations. We examine the performance of our method for reference simulations spanning a broad range of optical properties relevant for diffuse optical imaging of biological tissues. Our predictions are computed using the variance, covariance, and skewness of the photon weight, path length, and collision distributions generated by the reference simulation. Results We find that our methodology performs best when used in conjunction with reference cMC simulations that utilize Russian Roulette (RR) method. Specifically, we demonstrate that for a proximal detector placed immediately adjacent to the source, we can estimate the pMC relative error within 5% of the true value for scattering perturbations in the range of [ - 15 % , + 20 % ] . For a distal detector placed at ∼ 3 transport mean free paths relative to the source, our method provides relative error estimates within 20% for scattering perturbations in the range of [ - 8 % , + 15 % ] . Moreover, reference simulations performed at lower ( μ s ' / μ a ) values showed better performance for both proximal and distal detectors. Conclusions These findings indicate that reference simulations utilizing continuous absorption weighting (CAW) with the Russian Roulette method and executed using optical properties with a low ( μ s ' / μ a ) ratio spanning the desired range of μ s values, are highly advantageous for the deployment of pMC to obtain radiative transport estimates over a wide range of optical properties.
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Meziane Elotmani A, Messerschmidt-Roth A, Nehme A, Müller HH, Sekundo W. Comparison of intraocular lens power calculation formulas with and without total keratometry and ray tracing in patients with previous myopic SMILE. J Cataract Refract Surg 2023; 49:467-473. [PMID: 36700932 DOI: 10.1097/j.jcrs.0000000000001139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 01/03/2023] [Indexed: 01/27/2023]
Abstract
PURPOSE To evaluate the prediction error (PE) variance and absolute median PE of different intraocular lens (IOL) calculation formulas including last-generation formulas such as Barrett True-K with K, Okulix and total keratometry (TK)-based calculations with Haigis, and Barrett True-K in a simulation model in post-small-incision lenticule extraction (SMILE) eyes. SETTINGS Department of Ophthalmology, University Hospital Marburg, Marburg, Germany. DESIGN Prospective study. METHODS Preoperative measurements included IOL power calculation before and after SMILE surgery. The target refraction was set to be the lowest myopic refractive error in pre-SMILE eyes. The IOL power targeting at the lowest myopic refractive error in pre-SMILE eyes was selected for the post-SMILE IOL calculation of the same eye. The difference between the predicted refraction of pre- and post-SMILE eyes with the same IOL power was defined as IOL difference. The refractive change induced by SMILE was defined as the difference between preoperative and postoperative manifest refraction. RESULTS 98 eyes from 49 patients underwent bilateral myopic SMILE. The PE variance of Okulix was not significantly different compared with Barrett True-K with TK ( P = .471). The SDs of the mean PEs were ±0.413 D (Haigis-TK), ±0.453 D (Okulix), ±0.471 D (Barrett True-K with TK), ±0.556 D (Haigis-L), and ±0.576 D (Barrett True-K with K). The mean absolute PE was 0.340 D, 0.353 D, 0.404 D, 0.511 D, and 0.715 D for Haigis-TK, Okulix, Barrett True-K with TK, Barrett True-K with K, and Haigis-L, respectively. The highest percentage of eyes within ±0.50 D was achieved by Okulix, followed by Haigis-TK, Barrett True-K with TK, Barrett True-K with K, and Haigis-L. CONCLUSIONS Results suggest that Haigis in combination with TK, Okulix, and Barrett True-K with and without TK offer good options for accurate IOL power calculation after SMILE. Haigis-L showed a tendency for myopic shift in eyes after previous SMILE.
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Taroni L, Hoffer KJ, Pellegrini M, Lupardi E, Savini G. Comparison of the new Hoffer QST with 4 modern accurate formulas. J Cataract Refract Surg 2023; 49:378-384. [PMID: 36729423 DOI: 10.1097/j.jcrs.0000000000001126] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 12/12/2022] [Indexed: 02/03/2023]
Abstract
PURPOSE To investigate the new Hoffer QST (Savini/Taroni) formula (HQST) and compare it with the original Hoffer Q (HQ) and 4 latest generation formulas. SETTING I.R.C.C.S.-G.B. Bietti Foundation, Rome, Italy. DESIGN Retrospective case series. METHODS Refractive outcomes of the HQST, Barrett Universal II (BUII), Emmetropia Verifying Optical (EVO) 2.0, HQ, Kane, and Radial Basis Function (RBF) 3.0 formulas were compared. Subgroup analysis was performed in short (<22 mm) and long (>25 mm) axial length eyes. The SD of the prediction error (PE) was investigated using the heteroscedastic method. RESULTS 1259 eyes of 1259 patients divided in a White group (n=696), implanted with the AcriSof SN60AT (Alcon Labs), and an Asian group (n=563), implanted with the SN60WF (Alcon Labs), were investigated. In the Asian group, the heteroscedastic method did not disclose any significant difference among the SD of the 4 modern formulas (range from 0.333 to 0.346 D), whereas the SD of the HQ formula (0.384 D) was significantly higher. Compared with the original HQ formula, in both White and Asian groups, the HQST formula avoided the mean myopic PE in short eyes and the mean hyperopic PE in long eyes. CONCLUSIONS The new HQST formula was superior to the original HQ formula and reached statistical and clinical results comparable with those achieved by the BUII, EVO, Kane, and RBF formulas.
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Scherrer JR, Lynch GF, Zhang JJ, Fee MS. An optical design enabling lightweight and large field-of-view head-mounted microscopes. Nat Methods 2023; 20:546-549. [PMID: 36928075 DOI: 10.1038/s41592-023-01806-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 01/30/2023] [Indexed: 03/18/2023]
Abstract
Here we present a fluorescence microscope light path that enables imaging, during free behavior, of thousands of neurons in mice and hundreds of neurons in juvenile songbirds. The light path eliminates traditional illumination optics, allowing for head-mounted microscopes that have both a lower weight and a larger field of view (FOV) than previously possible. Using this light path, we designed two microscopes: one optimized for FOV (~4 mm FOV; 1.4 g), and the other optimized for weight (1.0 mm FOV; 1.0 g).
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Voytsekhivskyy OV, Hoffer KJ, Tutchenko L, Cooke DL, Savini G. Accuracy of 24 IOL Power Calculation Methods. J Refract Surg 2023; 39:249-256. [PMID: 37040214 DOI: 10.3928/1081597x-20230131-01] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
Abstract
PURPOSE To scrutinize the accuracy of 24 intraocular lens (IOL) power calculation formulas in unoperated eyes. METHODS In a series of consecutive patients undergoing phacoemulsification and implantation of the Tecnis 1 ZCB00 IOL (Johnson & Johnson Vision), the following formulas were evaluated: Barrett Universal II, Castrop, EVO 2.0, Haigis, Hoffer Q, Hoffer QST, Holladay 1, Holladay 2, Holladay 2 (AL Adjusted), K6 (Cooke), Kane, Karmona, LSF AI, Naeser 2, OKULIX, Olsen (OLCR), Olsen (standalone), Panacea, PEARL-DGS, RBF 3.0, SRK/T, T2, VRF, and VRF-G. The IOLMaster 700 (Carl Zeiss Meditec AG) was used for biometric measurements. With optimized lens constants, the mean prediction error (PE) and its standard deviation (SD), the median absolute error (MedAE), the mean absolute error (MAE), and the percentage of eyes with prediction erros within ±0.25, ±0.50, ±0.75, ±1.00, and ±2.00 D were analyzed. RESULTS Three hundred eyes of 300 patients were enrolled. The heteroscedastic method revealed statistically significant differences (P < .05) among formulas. Newly developed methods such as the VRF-G (standard deviation [SD] ±0.387 D), Kane (SD ±0.395 D), Hoffer QST (SD ±0.404 D), and Barrett Universal II (SD ±0.405) were more accurate than older formulas (P < .05). These formulas also yielded the highest percentage of eyes with a PE within ±0.50 D (84.33%, 82.33%, 83.33%, and 81.33%, respectively). CONCLUSIONS Newer formulas (Barrett Universal II, Hoffer QST, K6, Kane, Karmona, RBF 3.0, PEARL-DGS, and VRF-G) were the most accurate predictors of postoperative refractions. [J Refract Surg. 2023;39(4):249-256.].
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Běhal J, Pirone D, Sirico D, Bianco V, Mugnano M, Del Giudice D, Cavina B, Kurelac I, Memmolo P, Miccio L, Ferraro P. On monocytes and lymphocytes biolens clustering by in flow holographic microscopy. Cytometry A 2023; 103:251-259. [PMID: 36028475 DOI: 10.1002/cyto.a.24685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 07/29/2022] [Accepted: 08/23/2022] [Indexed: 11/09/2022]
Abstract
Live cells act as biological lenses and can be employed as real-world optical components in bio-hybrid systems. Imaging at nanoscale, optical tweezers, lithography and also photonic waveguiding are some of the already proven functionalities, boosted by the advantage that cells are fully biocompatible for intra-body applications. So far, various cell types have been studied for this purpose, such as red blood cells, bacterial cells, stem cells and yeast cells. White Blood Cells (WBCs) play a very important role in the regulation of the human body activities and are usually monitored for assessing its health. WBCs can be considered bio-lenses but, to the best of our knowledge, characterization of their optical properties have not been investigated yet. Here, we report for the first time an accurate study of two model classes of WBCs (i.e., monocytes and lymphocytes) by means of a digital holographic microscope coupled with a microfluidic system, assuming WBCs bio-lens characteristics. Thus, quantitative phase maps for many WBCs have been retrieved in flow-cytometry (FC) by achieving a significant statistical analysis to prove the enhancement in differentiation among sphere-like bio-lenses according to their sizes (i.e., diameter d) exploiting intensity parameters of the modulated light in proximity of the cell optical axis. We show that the measure of the low intensity area (S: I z < I th z ) in a fixed plane, is a feasible parameter for cell clustering, while achieving robustness against experimental misalignments and allowing to adjust the measurement sensitivity in post-processing. 2D scatterplots of the identified parameters (d-S) show better differentiation respect to the 1D case. The results show that the optical focusing properties of WBCs allow the clustering of the two populations by means of a mere morphological analysis, thus leading to the new concept of cell-optical-fingerprint avoiding fluorescent dyes. This perspective can open new routes in biomedical sciences, such as the chance to find optical-biomarkers at single cell level for label-free diagnosis.
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Vandevenne MM, Webers VS, Segers MH, Berendschot TT, Zadok D, Dickman MM, Nuijts RM, Abulafia A. Accuracy of intraocular lens calculations in eyes with keratoconus. J Cataract Refract Surg 2023; 49:229-233. [PMID: 36314969 PMCID: PMC9981321 DOI: 10.1097/j.jcrs.0000000000001088] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 10/20/2022] [Accepted: 10/21/2022] [Indexed: 11/05/2022]
Abstract
PURPOSE To compare the prediction accuracy of the Barrett True-K for keratoconus with standard formulas (SRK/T, Barrett Universal II, and Kane) and the Kane keratoconus formula. SETTING Shaare Zedek Medical Center, Jerusalem, Israel, and University Eye Clinic, Maastricht, the Netherlands. DESIGN Multicenter retrospective case series. METHODS Eyes with stable keratoconus undergoing cataract surgery were included. The predicted refractions were calculated for SRK/T, Barrett Universal II, Barrett True-K for keratoconus (predicted and measured), Kane, and Kane adjusted for keratoconus formulas. Primary outcomes were prediction error (PE), absolute error (AE), and percentage of eyes with PE ±0.25 diopters (D), ±0.50 D, and ±1.00 D. Subgroup analyses were performed based on the severity of the keratoconus. RESULTS 57 eyes were included in the study. The PE was not significantly different from zero for SRK/T, Barrett True-K (predicted and measured), and Kane keratoconus formulas (range 0.09 to 0.22 D, P > .05). The AE of Barrett True-K predicted (median 0.14 D) and Barrett True-K measured (median 0.10 D) were significantly lower from Barrett Universal II (median 0.47 D) and Kane (median 0.50 D), P < .001. CONCLUSIONS The Barrett True-K formulas for keratoconus had higher prediction accuracy as compared with new generation formulas and a similar prediction accuracy as compared with the Kane keratoconus formula.
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Langenbucher A, Szentmáry N, Cayless A, Wendelstein J, Hoffmann P. Bootstrap Outlier Identification in Clinical Datasets for Lens Power Formula Constant Optimization. Curr Eye Res 2023; 48:263-269. [PMID: 36593748 DOI: 10.1080/02713683.2022.2108457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
PURPOSE Bootstrapping is a modern technique widely used in statistics to evaluate the performance of model parameters. The purpose of this study was to develop a strategy to identify and eliminate outliers in a dataset used for optimizing formula constants for lens power calculation. METHODS In a dataset with N = 888 clinical cases treated with a monofocal aspherical intraocular lens (XC1/XY1, Hoya) constants for the SRKT, Haigis and Castrop formula were optimized and the prediction error PE calculated. The PE was bootstrapped NB = 1000 times, and the mean and trimmed mean of the bootstrapped PE were derived to generate the Bootlier plot showing the probability density function of the mean minus trimmed mean. With outliers this Bootlier plot shows some multimodality, and a Bootlier Index was extracted as a measure for multimodality. Outliers were removed from the tails of the PE distribution in a stepwise fashion until the Bootlier Index fell below a threshold of 0.001. RESULTS With the entire dataset the mean/SD/median/mean absolute/root mean squared PE using the optimized formula constants were -0.0045/0.44415/0.0134/0.3406/0.4412 dpt with SRKT, 0.0065/0.3711/-0.0056/0.2830/0.3710 dpt with Haigis, and 0.0034/0.3452/0.0023/0.2683/0.3451 dpt with the Castrop formula. After identifying and removing outliers the respective metrics for the PE were -0.0036/0.4028/0.0134/0.3205/0.4026 dpt for the SRKT (13 cases removed), 0.0050/0.3375/-0.0056/0.2656/0.3373 dpt with Haigis (11 cases removed), and 0.0035/0.3168/0.0023/0.2531/0.3166 dpt with Castrop (11 cases removed). The multimodality in the Bootlier plots was reduced from 0/0.1567/0.0587/0.0258/0.0007/0 with SRKT, 0/0.0981/0.0261/0.0202/0.0003/0 with Haigis, and 0.0006/0.0006/0.0161/0.0191/0.0005/0 with Castrop for the entire dataset to values below 1e-3 for trimming both tails of the PE distribution by ⅛, ¼, ½, 1, 2.5, and 5% respectively. CONCLUSION We were able to prove that bootstrapping with outlier identification based on Bootlier plots and the Bootlier Index is a powerful tool to clean a dataset of outliers for formula constant optimization.
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Khan A, Rangu N, Murphy DA, Cooke DL, Siatkowski RL, Mittal A, Wendelstein JA, Riaz KM. Standard vs total keratometry for intraocular lens power calculation in cataract surgery combined with DMEK. J Cataract Refract Surg 2023; 49:239-245. [PMID: 36804866 DOI: 10.1097/j.jcrs.0000000000001106] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Accepted: 11/18/2022] [Indexed: 02/23/2023]
Abstract
PURPOSE To compare the prediction accuracy of standard keratometry (K) and total keratometry (TK) for intraocular lens (IOL) power calculation in eyes undergoing combined cataract surgery and Descemet membrane endothelial keratoplasty (triple DMEK). SETTING Tertiary care academic referral center. DESIGN Retrospective case series. METHODS Review of 83 eyes (63 patients) that underwent triple DMEK between 2019 and 2021. Biometry measurements were obtained using a swept-source optical biometer (IOLMaster 700). 63 eyes were used for statistical analysis. Mean error, mean absolute error (MAE), SD, median absolute error, maximum absolute error, root mean squared prediction error, and the percentage of eyes within prediction errors of ±0.50 diopters (D) and ±1.00 D were calculated for 9 multivariate and third-generation formulas using K and TK values (Barrett Universal II, Yeo EVO 2.0, Cooke K6, Kane, Pearl-DGS, Haigis, Holladay 1, Hoffer Q, and SRK/T). Formulas were additionally tested by using the prediction for an IOL power 1 D below the IOL used (IOLup1D). RESULTS For all formulas, MAE was lower for K than for TK by an average of 0.21 D. The lowest MAE value observed was 0.67 D for "adjusted" SRK/T using K, and the highest MAE values observed were 1.24 D and 1.24 D for nonadjusted Hoffer Q and Haigis using TK, respectively. Overall, lower MAE values were observed for multivariate formulas and SRK/T. CONCLUSIONS In triple DMEK eyes, the prediction accuracy of K was higher than that of TK. The most accurate formulas were SRK/T and multivariate formulas using K with the IOLup1D adjustment.
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Jeon S, Taroni L, Lupardi E, Hoffer KJ, Fontana L, Schiano-Lomoriello D, Kwon H, Savini G. Accuracy of Nine Formulas to Calculate the Powers of an Extended Depth-of-Focus IOL Using Two SS-OCT Biometers. J Refract Surg 2023; 39:158-164. [PMID: 36892239 DOI: 10.3928/1081597x-20221221-03] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2023]
Abstract
PURPOSE To evaluate the accuracy of nine formulas to calculate the power of a new extended depth-of-focus intraocular lens (EDOF IOL), the AcrySof IQ Vivity (Alcon Laboratories, Inc), using measurements from two optical biometers, the IOLMaster 700 (Carl Zeiss Meditec AG) and Anterion (Heidelberg Engineering GmbH). METHODS After constant optimization, the accuracy of these formulas was analyzed in 101 eyes: Barrett Universal II, EVO 2.0, Haigis, Hoffer Q, Holladay 1, Kane, Olsen, RBF 3.0, and SRK/T. Both standard and total keratometry from the IOLMaster 700 and standard keratometry from the Anterion were used for each formula. RESULTS Constant optimization provided slightly different values for the A-constant, which ranged between 118.99 and 119.16, depending on the formula and the optical biometer. According to the heteroscedastic test, within each keratometry modality the standard deviation of the SRK/T was significantly higher compared to that of the Holladay 1, Kane, Olsen, and RBF 3.0 formulas. The SRK/T formula provided less accurate results also when the absolute prediction errors were compared by Friedman test. According to McNemar's test with Holm corrections, statistically significant differences were found within each keratometry modality between the percentage of eyes with a prediction error within ±0.25 diopters obtained with the Olsen formula compared to the Holladay 1 and Hoffer Q formulas. CONCLUSIONS Constant optimization remains a mandatory step to achieve the best outcomes with the new EDOF IOL: the same constant should not be used for all formulas and for both optical biometers. Different statistical tests revealed that older IOL formulas have lower accuracy compared to newer formulas. [J Refract Surg. 2023;39(3):158-164.].
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Ogiwara Y, Iwata N, Furumi S. Dominant Factors Affecting Rheological Properties of Cellulose Derivatives Forming Thermotropic Cholesteric Liquid Crystals with Visible Reflection. Int J Mol Sci 2023; 24:ijms24054269. [PMID: 36901701 PMCID: PMC10002051 DOI: 10.3390/ijms24054269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 02/14/2023] [Accepted: 02/16/2023] [Indexed: 02/24/2023] Open
Abstract
Hydroxypropyl cellulose (HPC) derivatives with alkanoyl side chains are known to form thermotropic cholesteric liquid crystals (CLCs) with visible reflection. Although the widely investigated CLCs are requisite for tedious syntheses of chiral and mesogenic compounds from precious petroleum resources, the HPC derivatives easily prepared from biomass resources would contribute to the realization of environment-friendly CLC devices. In this study, we report the linear rheological behavior of thermotropic CLCs of HPC derivatives possessing alkanoyl side chains of different lengths. In addition, the HPC derivatives have been synthesized by the complete esterification of hydroxy groups in HPC. The master curves of these HPC derivatives were almost identical at reference temperatures, with their light reflection at 405 nm. The relaxation peaks appeared at an angular frequency of ~102 rad/s, suggesting the motion of the CLC helical axis. Moreover, the dominant factors affecting the rheological properties of HPC derivatives were strongly dependent on the CLC helical structures. Further, this study provides one of the most promising fabrication strategies for the highly oriented CLC helix by shearing force, which is indispensable to the development of advanced photonic devices with eco-friendliness.
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Bracamonte AG. Current Advances in Nanotechnology for the Next Generation of Sequencing (NGS). BIOSENSORS 2023; 13:260. [PMID: 36832027 PMCID: PMC9954403 DOI: 10.3390/bios13020260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 02/03/2023] [Accepted: 02/09/2023] [Indexed: 06/18/2023]
Abstract
This communication aims at discussing strategies based on developments from nanotechnology focused on the next generation of sequencing (NGS). In this regard, it should be noted that even in the advanced current situation of many techniques and methods accompanied with developments of technology, there are still existing challenges and needs focused on real samples and low concentrations of genomic materials. The approaches discussed/described adopt spectroscopical techniques and new optical setups. PCR bases are introduced to understand the role of non-covalent interactions by discussing about Nobel prizes related to genomic material detection. The review also discusses colorimetric methods, polymeric transducers, fluorescence detection methods, enhanced plasmonic techniques such as metal-enhanced fluorescence (MEF), semiconductors, and developments in metamaterials. In addition, nano-optics, challenges linked to signal transductions, and how the limitations reported in each technique could be overcome are considered in real samples. Accordingly, this study shows developments where optical active nanoplatforms generate signal detection and transduction with enhanced performances and, in many cases, enhanced signaling from single double-stranded deoxyribonucleic acid (DNA) interactions. Future perspectives on miniaturized instrumentation, chips, and devices aimed at detecting genomic material are analyzed. However, the main concept in this report derives from gained insights into nanochemistry and nano-optics. Such concepts could be incorporated into other higher-sized substrates and experimental and optical setups.
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Parker M, Mayes SA, Browning CM, Deal J, Gunn-Mayes S, Annamdevula NS, Rich TC, Leavesley SJ. Multifaceted mirror array illuminator for fluorescence excitation-scanning spectral imaging microscopy. JOURNAL OF BIOMEDICAL OPTICS 2023; 28:026502. [PMID: 36761255 PMCID: PMC9907356 DOI: 10.1117/1.jbo.28.2.026502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 01/17/2023] [Indexed: 06/18/2023]
Abstract
SIGNIFICANCE Hyperspectral imaging (HSI) technologies offer great potential in fluorescence microscopy for multiplexed imaging, autofluorescence removal, and analysis of autofluorescent molecules. However, there are also associated trade-offs when implementing HSI in fluorescence microscopy systems, such as decreased acquisition speed, resolution, or field-of-view due to the need to acquire spectral information in addition to spatial information. The vast majority of HSI fluorescence microscopy systems provide spectral discrimination by filtering or dispersing the fluorescence emission, which may result in loss of emitted fluorescence signal due to optical filters, dispersive optics, or supporting optics, such as slits and collimators. Technologies that scan the fluorescence excitation spectrum may offer an approach to mitigate some of these trade-offs by decreasing the complexity of the emission light path. AIM We describe the development of an optical technique for hyperspectral imaging fluorescence excitation-scanning (HIFEX) on a microscope system. APPROACH The approach is based on the design of an array of wavelength-dependent light emitting diodes (LEDs) and a unique beam combining system that uses a multifurcated mirror. The system was modeled and optimized using optical ray trace simulations, and a prototype was built and coupled to an inverted microscope platform. The prototype system was calibrated, and initial feasibility testing was performed by imaging multilabel slide preparations. RESULTS We present results from optical ray trace simulations, prototyping, calibration, and feasibility testing of the system. Results indicate that the system can discriminate between at least six fluorescent labels and autofluorescence and that the approach can provide decreased wavelength switching times, in comparison with mechanically tuned filters. CONCLUSIONS We anticipate that LED-based HIFEX microscopy may provide improved performance for time-dependent and photosensitive assays.
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