Article
Biochemical Research Methods
Yiwei Chen, Silvestre Manzanera, Juan Mompean, Daniel Ruminski, Ireneusz Grulkowski, Pablo Artal
Summary: An algorithm utilizing oblique scanning and image stitching is proposed to increase the OCT imaging volume of the crystalline lens. Results show that the method can provide around 17% additional volumetric lens coverage compared to regular imaging methods.
BIOMEDICAL OPTICS EXPRESS
(2021)
Article
Biochemical Research Methods
Duardo Martinez-Enriquez, Andrea Curatolo, Alberto de Castro, Judith S. Birkenfeld, Ana M. Gonzalez, Ashik Mohamed, Marco Ruggeri, Fabrice Manns, Zvietcovich Fernando, Susana Marcos
Summary: In this study, we successfully estimated the full shape of the in vivo crystalline lens using the eigenlenses method, which only utilizes information visible through the pupil. Compared to previous methods, eigenlenses showed improved repeatability, robustness, and computational resource utilization in estimating crystalline lens shape. Eigenlenses can efficiently describe the full shape changes of the crystalline lens with accommodation and refractive error.
BIOMEDICAL OPTICS EXPRESS
(2023)
Article
Biochemical Research Methods
Fabrice Manns, Arthur Ho
Summary: This paper presents an analytical paraxial model of the gradient lens of the eye, which accurately represents the refractive index distribution and paraxial characteristics. The model can simulate changes in lens power with age and accommodation, providing insights into the optics of the eye.
BIOMEDICAL OPTICS EXPRESS
(2022)
Article
Optics
Rafael Navarro, Sergio Baquedano, Ana Sanchez-Cano
Summary: A new type of lens with two gradients of refractive index and curvature is introduced, resembling the structure of an onion with each layer being a meniscus lens. The internal distribution adapts to the external geometry, with consideration of a constant gradient of the curvature radius.
Article
Ophthalmology
Heather A. Anderson, Melissa D. Bailey, Ruth E. Manny, Chiu-Yen Kao
Summary: This study investigated the relationship between ciliary muscle thickness (CMT), age, and refractive error in adults with Down syndrome. The findings showed that the CMT in individuals with Down syndrome was similar to previous reports, and thinning CMT was associated with increasing age.
OPHTHALMIC AND PHYSIOLOGICAL OPTICS
(2022)
Article
Ophthalmology
Emmanuel Owusu, Nahrain M. Shasteen, G. Lynn Mitchell, Melissa D. Bailey, Chiu-Yen Kao, Andrew J. Toole, Kathryn Richdale, Marjean T. Kulp
Summary: This study found that individuals with accommodative insufficiency have thinner ciliary muscles in the apical region and the ciliary muscle can thicken in response to increased workload. This may explain why symptoms improve with accommodative/vergence therapy.
OPHTHALMIC AND PHYSIOLOGICAL OPTICS
(2023)
Article
Optics
KunYuan Yao, JianQi Shen
Summary: The interferometric particle imaging (IPI) technique uses scattered light's angular oscillations for droplet or bubble sizing by evaluating refractive index and extracting particle diameter from interferogram images. This method, utilizing two CCD cameras at different scattering angles, was validated with water droplets and glycerol droplets suspended in air.
OPTICS AND LASER TECHNOLOGY
(2021)
Article
Biochemical Research Methods
Eduardo Martinez-Enriquez, Bianca Maceo Heilman, Alberto de Castro, Ashik Mohamed, Marco Ruggeri, Fermamdp Zvietcovich, Fabrice Manns, Susana Marcos
Summary: Quantifying the geometry of human crystalline lens as a function of age and accommodation is crucial for better treatments of cataract and presbyopia. This study validates the use of eigenlenses to estimate the full shape of dis-accommodated lenses in vivo. The results demonstrate that eigenlenses can accurately estimate the shape of dis-accommodated lenses.
BIOMEDICAL OPTICS EXPRESS
(2023)
Article
Biochemical Research Methods
Rafael Navarro, Veronica Lockett-Ruiz, Jose L. Lopez
Summary: In this paper, we present the formulation of a paraxial ray transfer matrix for onion-type GRIN lenses. The matrix is computed by multiplying translation and refraction matrices corresponding to the layers inside the lens. We derive the ABCD matrix using a differential approximation for the layer thickness, and calculate its elements by integrating the elements of a single-layer matrix. The resulting matrix offers a compact and simple expression for the total lens power.
BIOMEDICAL OPTICS EXPRESS
(2022)
Article
Optics
Zhang-Lang Lin, Pavel Loiko, Huang-Jun Zeng, Wen-Ze Xue, Ge Zhang, Simone Normani, Patrice Camy, Valentin Petrov, Xavier Mateos, Haifeng Lin, Haohai Yu, Huaijin Zhang, Junhai Liu, Li Wang, Weidong Chen
Summary: We present a Kerr-lens mode-locked laser utilizing an Yb3+-doped disordered calcium lithium niobium gallium garnet (Yb:CLNGG) crystal. By pumping with a spatially single-mode Yb fiber laser at 976nm, the Yb:CLNGG laser generates soliton pulses with a duration of 31 fs at 1056.8nm, achieving an average output power of 66mW and a pulse repetition rate of approximately 77.6MHz via soft-aperture Kerr-lens mode-locking. The Kerr-lens mode-locked laser reaches a maximum output power of 203mW for slightly longer pulses of 37fs at an absorbed pump power of 0.74W, corresponding to a peak power of 62.2kW and an optical efficiency of 20.3%.
Article
Ophthalmology
Antonio Queiros, Alejandro Cervino, Jose Manuel Gonzalez-Meijome
Summary: This study measured the refraction patterns of myopic eyes with spectacle lenses correction and lens-free emmetropes at different target distances. It was found that accommodation to very near targets (up to 0.20 m) makes the off-axis refraction of myopes wearing their spectacle correction similar to that of lens-free emmetropes, with a significant reduction in off-axis astigmatism observed.
Article
Engineering, Electrical & Electronic
Sourabh Sahu, Nitesh Mudgal, Ankit Agrawal, Ghanshyam Singh
Summary: This research paper presents the design and simulation of an optical biosensor using a ring resonator with strip and subwavelength grating waveguides. The biosensor aims to work in low-loss regions and prevent bending losses. Simulation analysis is performed to observe the sensing parameters. The biosensor can detect changes in resonant wavelength caused by changes in refractive index, making it suitable for a wide range of biosensing applications.
JOURNAL OF SENSORS
(2023)
Article
Biophysics
Katherine R. Knaus, AnnMarie Hipsley, Silvia S. Blemker
Summary: The ciliary muscle consists of three sections with different orientations that contract to deform and translate the lens during accommodation. A finite element model was created to predict the actions of the ciliary muscle sections in lens displacement. The model was calibrated and validated using experimental data to study the mechanical actions of each section.
BIOMECHANICS AND MODELING IN MECHANOBIOLOGY
(2021)
Article
Optics
Yu Zhang, Jiming Chen, Shuai Liu, Wei Jin, Siying Cheng, Yaxun Zhang, Zhihai Liu, Jianzhong Zhang, Libo Yuan
Summary: This study presents an all-fiber nonvolatile broadband optical switch using an all-optical method, where a phase change material is modulated on a tapered fiber to achieve logical control of transmitted light. The optical switch has fast response time, operates in the C-band, and exhibits high switching contrast, enabling possibilities for all-optical nonvolatile fiber optic communication.
Article
Engineering, Electrical & Electronic
Tien-Chen Yang, Yi-Kai Chen, Malcolm Ng Mou Kehn
Summary: This paper presents a metasurface cloak that can make any shape and size region invisible on a flat lens in the microwave band. The crafty design technique using the ray insertion method enables the manipulation of electromagnetic surface waves' paths. The prototype of the cloak was manufactured and measured, confirming its effectiveness.
IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS
(2023)
Article
Ophthalmology
Manoj K. Manoharan, Swapnil Thakur, Subalakshmi Dellhi, Pavan K. Verkicharla
Summary: This study aimed to investigate the association between various refractive error components and reduced visual acuity in individuals with myopia, with and without pathologic myopia lesions. The study found that high sphere, high cylinder, and certain astigmatism orientations were significantly associated with reduced visual acuity.
OPHTHALMIC AND PHYSIOLOGICAL OPTICS
(2023)
Article
Ophthalmology
Rohit Dhakal, Jagadesh Rao Rudrapankte, Harsha S. N. S. Chittajallu, John G. Lawrenson, Byki Huntjens, Rakhee Shah, Pavan K. Verkicharla
Summary: The study developed a clip-on light tracker (MyLyt) for real-time estimation of light exposure and validated its accuracy and feasibility in different environments. The results demonstrated that MyLyt showed good repeatability, strong correlation, and comparable values with a factory-calibrated digital lux meter, making it suitable for tracking light exposure patterns.
OPHTHALMIC AND PHYSIOLOGICAL OPTICS
(2023)
Article
Ophthalmology
Rakesh Maldoddi, Swapnil Thakur, Pavan K. K. Verkicharla
Summary: The purpose of this study was to investigate the effects of near work and time outdoors on axial length and myopia prevention. The results showed that a 15-minute reading task, regardless of the location or reading environment, led to a significant increase in axial length. These findings highlight the importance of considering the impact of near work on myopia control and the need for increased time outdoors.
OPHTHALMIC AND PHYSIOLOGICAL OPTICS
(2023)
Article
Ophthalmology
David A. Atchison, Jos J. Rozema
Summary: This study provides an overview of the misconceptions and potential artefacts associated with measuring peripheral refractive error and eye length, and discusses their implications for determining retinal shape and myopia development. Several issues were identified, such as the relationship between peripheral refractive error and myopia development, and the accuracy of measuring peripheral eye length using an optical biometer. Some of these issues can be addressed, while others require further investigation.
OPHTHALMIC AND PHYSIOLOGICAL OPTICS
(2023)
Article
Ophthalmology
Rohit Dhakal, Byki Huntjens, Rakhee Shah, John G. Lawrenson, Pavan K. Verkicharla
Summary: This study aimed to investigate the variation in the spectral composition of ambient light in different outdoor/indoor locations, time of a day, and seasons. The results showed that regardless of the variation in location, time, day, and season, outdoor locations always had significantly higher spectral power than indoor locations, and the relative percentage composition of short, middle, and long wavelengths did not differ significantly across locations.
OPHTHALMIC AND PHYSIOLOGICAL OPTICS
(2023)
Letter
Ophthalmology
Swapnil Thakur, Pavan K. Verkicharla
OPHTHALMIC AND PHYSIOLOGICAL OPTICS
(2023)
Article
Ophthalmology
Manoj K. K. Manoharan, David A. A. Atchison, Pavan K. K. Verkicharla
Summary: The study found that the retinal shapes of anisometropic eyes with higher myopia are similar to those of isometropic eyes with the same refraction along the horizontal meridian.
OPTOMETRY AND VISION SCIENCE
(2023)
Article
Ophthalmology
Annabelle Seddon, Hanna M. Chaki, Hang-My J. D. Phan, Jessica G. Spink, Matthew L. P. Ha, Surini Wijesuriya, David A. Atchison, Andrew Carkeet
Summary: This study investigated how unequal image sizes between the eyes affect visual acuity. The results showed that induced aniseikonia slightly reduced binocular visual acuity, but the change was small and cannot be used as a diagnostic marker in clinical settings.
CLINICAL AND EXPERIMENTAL OPTOMETRY
(2023)
Letter
Ophthalmology
Rakesh Maldoddi, Swapnil Thakur, Pavan K. K. Verkicharla
OPHTHALMIC AND PHYSIOLOGICAL OPTICS
(2023)
Article
Ophthalmology
Satish Kumar Gupta, Ranjay Chakraborty, Pavan Kumar Verkicharla
Summary: This study investigated the association between relative peripheral refraction (RPR) and corresponding relative peripheral multifocal electroretinogram (mfERG) responses in young adults. The results showed that relative peripheral mfERG signals are not associated with RPR.
OPHTHALMIC AND PHYSIOLOGICAL OPTICS
(2023)
Article
Ophthalmology
Martin de Tomas, Abel Szeps, Gabriel Martin, Juan Manuel Suarez, David A. Atchison, Jos J. Rozema, Rafael Iribarren
Summary: This study analyzed OCT images of retinal shadows caused by defocus and diffusion optics spectacles. The results showed obvious retinal shadows in the periphery of the images, while the central area remained clear. The discrepancy between the actual size of the shadows and their appearance in the OCT images was attributed to the scanning OCT beam not being parallel to the optical axis. With device-specific correction, retinal OCT images can help visualize the regions affected by defocus or lowered contrast induced by myopia control spectacles.
OPHTHALMIC AND PHYSIOLOGICAL OPTICS
(2023)
Article
Clinical Neurology
Ioannis N. Petropoulos, Fatima Al-Shibani, Gulfidan Bitirgen, Georgios Ponirakis, Adnan Khan, Hoda Gad, Ziyad R. Mahfoud, Heba Altarawneh, Muhammad Hassan Rehman, Karen John, Dhabia Al-Merekhi, Pooja George, Ali Ulvi Uca, Ahmet Ozkagnici, Faiza Ibrahim, Reny Francis, Beatriz Canibano, Dirk Deleu, Ahmed El-Sotouhy, Surjith Vattoth, Ahmed Own, Ashfaq Shuaib, Naveed Akhtar, Saadat Kamran, Rayaz A. Malik
Summary: Corneal confocal microscopy (CCM) can be used to detect axonal loss in multiple sclerosis (MS) patients. This study found progressive corneal and retinal axonal loss over a 2-year follow-up period, especially in patients with more active disease. CCM may serve as an imaging biomarker of axonal loss in MS.
THERAPEUTIC ADVANCES IN NEUROLOGICAL DISORDERS
(2023)
Article
Genetics & Heredity
Aziz Belkadi, Gaurav Thareja, Adnan Khan, Nisha Stephan, Shaza Zaghlool, Anna Halama, Ayeda Abdulsalam Ahmed, Yasmin A. Mohamoud, Joel Malek, Karsten Suhre, Rayaz A. Malik
Summary: This study uses ophthalmic imaging to identify novel retinal and corneal abnormalities in patients with Bardet-Biedl syndrome, expanding the phenotype of this disease.
BMC MEDICAL GENOMICS
(2023)
Article
Ophthalmology
David A. Atchison, David L. Cooke
Summary: A thin lens technique was developed to determine how the effective powers of toric monofocal intraocular lenses (IOLs) are influenced by tilt and refractive errors. The correction required at the front of the eye and the power of an IOL that would compensate for the tilt were determined through a series of steps.
OPHTHALMIC AND PHYSIOLOGICAL OPTICS
(2023)
Article
Clinical Neurology
Ioannis N. Petropoulos, Karen John, Fatima Al-Shibani, Georgios Ponirakis, Adnan Khan, Hoda Gad, Ziyad R. Mahfoud, Heba Altarawneh, Muhammad Hassan Rehman, Dhabia Al-Merekhi, Pooja George, Faiza Ibrahim, Reny Francis, Beatriz Canibano, Dirk Deleu, Ahmed El-Sotouhy, Surjith Vattoth, Mark Stettner, Ahmed Own, Ashfaq Shuaib, Naveed Akhtar, Saadat Kamran, Rayaz A. Malik
Summary: This study found that corneal immune cells in patients with multiple sclerosis (MS) undergo changes related to disease progression and treatment status, and are associated with axonal degeneration. Evaluation of corneal immune cells using corneal confocal microscopy can provide insights into the inflammation, disease progression, and treatment effects in MS patients.
THERAPEUTIC ADVANCES IN NEUROLOGICAL DISORDERS
(2023)