On the Relationship between Corneal Biomechanics, Macrostructure, and Optical Properties

Optical properties of the cornea are responsible for correct vision; the ultrastructure allows optical transparency, and the biomechanical properties govern the shape, elasticity, or stiffness of the cornea, affecting ocular integrity and intraocular pressure. Therefore, the optical aberrations, corneal transparency, structure, and biomechanics play a fundamental role in the optical quality of human vision, ocular health, and refractive surgery outcomes. However, the inter-relationships of those properties are not yet reported at a macroscopic scale within the hierarchical structure of the cornea. This work explores the relationships between the biomechanics, structure, and optical properties (corneal aberrations and optical density) at a macro-structural level of the cornea through dual Placido–Scheimpflug imaging and air-puff tonometry systems in a healthy young adult population. Results showed correlation between optical transparency, corneal macrostructure, and biomechanics, whereas corneal aberrations and in particular spherical terms remained independent. A compensation mechanism for the spherical aberration is proposed through corneal shape and biomechanics.

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On the Relationship between Corneal Biomechanics, Macrostructure and Optical Properties

10.20944/preprints202110.0443.v1 ◽

2021 ◽

Author(s):

Francisco J. Ávila ◽

Laura Remón ◽

Maria Concepción Marcellán

Keyword(s):

Optical Properties ◽

Biomechanical Properties ◽

Optical Quality ◽

Optical Transparency ◽

Optical Aberrations ◽

Corneal Aberrations ◽

Scheimpflug Imaging ◽

The Hierarchical Structure ◽

The Relationship

Optical properties of the cornea are responsible for correct vision, ultrastructure allows optical transparency and biomechanical properties governs the shape, elasticity or stiffness of the cor-nea affecting ocular integrity and intraocular pressure. Therefore, optical aberrations, corneal transparency, structure and biomechanics play a fundamental role in the optical quality of hu-man vision, ocular health and refractive surgery outcomes. However, the convergence of those properties is not yet reported at macroscopic scale within the hierarchical structure of the cornea. This work explores the relationships between biomechanics, structure and optical properties (corneal aberrations and optical density) at macrostructural level of the cornea through dual Placido-Scheimpflug imaging and air-puff tonometry systems in a healthy young adult popula-tion. Results showed convergence between optical transparency, corneal macrostructure and biomechanics.

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Changes of Corneal Wavefront Aberrations in Dry Eye Patients after Treatment with Artificial Lubricant Drops

Journal of Ophthalmology ◽

10.1155/2016/1342056 ◽

2016 ◽

Vol 2016 ◽

pp. 1-11 ◽

Cited By ~ 2

Author(s):

Ning Lu ◽

Fangyu Lin ◽

Zhu Huang ◽

Qin He ◽

Wei Han

Keyword(s):

Dry Eye ◽

Spherical Aberration ◽

Optical Quality ◽

Control Group ◽

Eye Drops ◽

Artificial Eye ◽

Corneal Surface ◽

Wavefront Aberrations ◽

Corneal Aberrations

Purpose.To evaluate the corneal aberration changes in dry eye patients after treatment with artificial eye drops.Methods.Thirty mild to moderate dry eye patients treated with artificial eye drops and twenty comparable dry eye patients were recruited as controls. Anterior corneal aberrations over 3 mm and 5 mm analytical zones including total, 3rd to 5th high order aberrations (HOAs), spherical aberration (SA), and vertical (V-coma) and horizontal coma (H-coma) obtained from corneal topography data at baseline and 2 weeks after treatment were evaluated.Results.For 3 mm zone, trefoils, V-coma, H-coma terms, and 3rd and 5th HOAs were significantly decreased (p<0.05) in the treatment group. For 5 mm zone, instillation of eye drops reduced H-coma, SA terms, 3rd to 5th orders, and total HOAs all showed a significant decrease (p<0.05). The root mean square analysis of the Zernike terms also showed similar statistical results. For control group, all individual terms and total HOAs did not have significant changes over 3 mm and 5 mm zones (p>0.05).Conclusions.Treatment with artificial eye drops can effectively improve the corneal optical quality of dry eye patients by ameliorating the HOAs of anterior corneal surface.

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Physiological and ecological consequences of the water optical properties degradation on reef corals

Coral Reefs ◽

10.1007/s00338-021-02133-7 ◽

2021 ◽

Author(s):

Tomás López-Londoño ◽

Claudia T. Galindo-Martínez ◽

Kelly Gómez-Campo ◽

Luis A. González-Guerrero ◽

Sofia Roitman ◽

...

Keyword(s):

Optical Properties ◽

Population Decline ◽

Light Availability ◽

Potential Effect ◽

Optical Quality ◽

Light Penetration ◽

Reef Corals ◽

Orbicella Faveolata ◽

Light Quantity ◽

Reduced Light

AbstractDegradation of water optical properties due to anthropogenic disturbances is a common phenomenon in coastal waters globally. Although this condition is associated with multiple drivers that affect corals health in multiple ways, its effect on light availability and photosynthetic energy acquisition has been largely neglected. Here, we describe how declining the water optical quality in a coastal reef exposed to a turbid plume of water originating from a man-made channel compromises the functionality of the keystone coral species Orbicella faveolata. We found highly variable water optical conditions with significant effects on the light quantity and quality available for corals. Low-light phenotypes close to theoretical limits of photoacclimation were found at shallow depths as a result of reduced light penetration. The estimated photosynthetically fixed energy depletion with increasing depth was associated with patterns of colony mortality and vertical habitat compression. A numerical model illustrates the potential effect of the progressive water quality degradation on coral mortality and population decline along the depth gradient. Collectively, our findings suggest that preserving the water properties seeking to maximize light penetration through the water column is essential for maintaining the coral reef structure and associated ecosystem services.

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Effect of Spherical Aberration on the Optical Quality after Implantation of Two Different Aspherical Intraocular Lenses

Journal of Ophthalmology ◽

10.1155/2017/8039719 ◽

2017 ◽

Vol 2017 ◽

pp. 1-6 ◽

Cited By ~ 4

Author(s):

Michael Lasta ◽

Kata Miháltz ◽

Illés Kovács ◽

Pia Veronika Vécsei-Marlovits

Keyword(s):

Contrast Sensitivity ◽

Pupil Size ◽

Spherical Aberration ◽

Optical Quality ◽

Intraocular Lenses ◽

Strehl Ratio ◽

Minimum Diameter ◽

Link Type ◽

Medical Optics ◽

Aspherical Iol

Purpose. To compare the effect of spherical aberration on optical quality in eyes with two different aspherical intraocular lenses. Methods. 120 eyes of 60 patients underwent phacoemulsification. In patients’ eyes, an aberration-free IOL (Aspira-aA; Human Optics) or an aberration-correcting aspherical IOL (Tecnis ZCB00; Abott Medical Optics) was randomly implanted. After surgery, contrast sensitivity and wavefront measurements as well as tilt and decentration measurements were performed. Results. Contrast sensitivity was significantly higher in eyes with Aspira lens under mesopic conditions with 12 cycles per degree (CPD) and under photopic conditions with 18 CPD (p=0.02). Wavefront measurements showed a higher total spherical aberration with a minimal pupil size of 4 mm in the Aspira group (0.05 ± 0.03) than in the Tecnis group (0.03 ± 0.02) (p=0.001). Strehl ratio was higher in eyes with Tecnis (0.28 ± 0.17) with a minimal pupil size larger than 5 mm than that with Aspira (0.16 ± 0.14) (p=0.04). In pupils with a minimum diameter of 4 mm spherical aberration had a significant effect on Strehl ratio, but not in pupils with a diameter less than 4 mm. Conclusions. Optical quality was better in eyes with the aberration-correcting Tecnis IOL when pupils were large. In contrast, this could not be shown in eyes with pupils under 4 mm or larger. This trial is registered with Clinicaltrials.gov NCT03224728.

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Theoretical Study of Effect of the Number of N,N-dimethyl-4-nitroaniline Units in Novel “Parallel Connection” Chromophores on Its Nonlinear Optical Properties

ISRN Physical Chemistry ◽

10.5402/2012/262563 ◽

2012 ◽

Vol 2012 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Chao-Zhi Zhang ◽

Hui Cao ◽

Zhao-Bing Guo

Keyword(s):

Optical Properties ◽

Absorption Maximum ◽

Nonlinear Optical ◽

Theoretical Study ◽

Semiempirical Method ◽

Nonlinear Optical Properties ◽

Optical Transparency ◽

First Hyperpolarizability ◽

Parallel Connection

Design of “parallel connection” chromophores could give a way of acquiring effective chromophores. The semiempirical method ZINDO was employed to study relationship between static first hyperpolarizabilities of “parallel connection” chromophores and the number of parallel nonconjugated N,N-dimethyl-4-nitroaniline (DMNA) units in the chromophore. The results show that the chromophore containing three parallel non-conjugated DMNA units exhibits the highest static first hyperpolarizability, which is 1.8 times that of chromophore DMNA. However, static first hyperpolarizabilities of the chromophores containing four or five DMNA units are very small. The absorption maximum wavelength (λmax) of “parallel connection” chromophores is remarkably shorter (34.9 nm–38.1 nm) than that of 1DMNA. Therefore, the “parallel connection” chromophore containing three DMNA units would be an effective chromophore with a large first hyperpolarizability and a good optical transparency. It could give a useful suggestion for designing effective chromophores containing parallel non-conjugated D-π-A units.

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Highly transparent polyimides derived from 2-phenyl-4,6-bis(4-aminophenoxy)pyrimidine and 1,3-bis(5-amino-2-pyridinoxy)benzene: preparation, characterization, and optical properties

RSC Advances ◽

10.1039/c5ra19167j ◽

2015 ◽

Vol 5 (125) ◽

pp. 103246-103254 ◽

Cited By ~ 13

Author(s):

Chunbo Wang ◽

Yue Guan ◽

Dongbo Tian ◽

Guodong Dang ◽

Daming Wang ◽

...

Keyword(s):

Optical Properties ◽

Optical Transparency

Heterocyclic polyimides were prepared from two novel diamines with anhydrides, which exhibit outstanding solubility and optical transparency properties.

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Plasma-Assisted MOCVD Growth of ZnO Thin Films

MRS Proceedings ◽

10.1557/proc-0892-ff18-06-ee09-06 ◽

2005 ◽

Vol 892 ◽

Cited By ~ 1

Author(s):

Maria Losurdo ◽

Maria Michela Giangregorio ◽

Pio Capezzuto ◽

Giovanni Bruno ◽

Graziella Malandrino ◽

...

Keyword(s):

Thin Films ◽

Optical Properties ◽

Vapor Deposition ◽

Metalorganic Chemical Vapor Deposition ◽

Chemical Vapor ◽

Optical Quality ◽

Zno Thin Films ◽

Zno Films ◽

Mocvd Growth ◽

Metalorganic Chemical

AbstractZnO thin films have been grown by metalorganic chemical vapor deposition (MOCVD) also plasma assisted (PA-MOCVD) on c-axis oriented sapphire (0001) and Si(001) substrates using the alternative Zn(TTA)2·tmed (HTTA=2-thenoyltrifluoroacetone,TMED=N,N,N’,N’-tetramethylethylendiamine) precursor. The structural, morphological and optical properties of ZnO films have been investigated. The results show that the O2 plasma assisted growth results in an improvement of the structure, in smoother morphologies and in a better optical quality with a sharp and intense exciton of ZnO films.

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Second-Order Nonlinear Optical Properties of a Polymer Exhibiting Optical Transparency Down to 340 nm

Journal of Macromolecular Science Part A ◽

10.1080/10601329409350115 ◽

1994 ◽

Vol 31 (12) ◽

pp. 2011-2018 ◽

Cited By ~ 1

Author(s):

M. Kamath ◽

C. E. Masse ◽

R. J. Jeng ◽

M. Cazeca ◽

X. L. Jiang ◽

...

Keyword(s):

Optical Properties ◽

Nonlinear Optical ◽

Second Order ◽

Nonlinear Optical Properties ◽

Optical Transparency

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Optical Properties of Doped Cd1−xMnxTe

MRS Proceedings ◽

10.1557/proc-89-281 ◽

1986 ◽

Vol 89 ◽

Author(s):

Y. Lansari ◽

N. C. Giles ◽

J. F. Schetzina ◽

P. Becia ◽

D. Kaiser

Keyword(s):

Optical Properties ◽

Low Temperature ◽

Spectral Range ◽

Room Temperature ◽

Far Infrared ◽

Optical Quality ◽

Structural Quality ◽

Reflectance Measurements ◽

Low Temperature Photoluminescence

AbstractThe introduction of phosphorus and arsenic dopants into bulk Cd1−xMnx Te crystals grown by the Bridgman-Stockbarger technique has been studieA-with respect to the resulting optical properties. Samples with a Mn composition in the range 0.10 < x < 0.30, both as-grown and annealed, were investigated. A combination of room temperature transmittance and reflectance measurements over the spectral range from the ultraviolet to the far infrared has been used to gain information concerning the structural quality of the samples. Low temperature photoluminescence measurements (1.6−5 K) were used to determine optical quality and excitonic energies.

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Optical Properties of KTP Crystals and Their Potential for Terahertz Generation

Crystals ◽

10.3390/cryst8080310 ◽

2018 ◽

Vol 8 (8) ◽

pp. 310 ◽

Cited By ~ 9

Author(s):

Alexander Mamrashev ◽

Nazar Nikolaev ◽

Valery Antsygin ◽

Yury Andreev ◽

Grigory Lanskii ◽

...

Keyword(s):

Optical Properties ◽

Second Harmonic ◽

Difference Frequency Generation ◽

Terahertz Wave ◽

Optical Quality ◽

Potassium Titanyl Phosphate ◽

Phase Matching ◽

Wide Range ◽

Parametric Processes ◽

Wave Conversion

High nonlinearity, wide transparency range and optical quality allowed potassium titanyl phosphate (KTiOPO4, KTP) crystals to be used in a wide range of nonlinear applications. The success of KTP usage in the visible and infrared (IR) ranges drives interest in applying it at longer wavelengths, that is, in the terahertz (THz) range. We use THz optical properties of KTP crystals measured by terahertz time-domain spectrometer (THz-TDS) and refractive index approximated in the form of Sellmeier equations to investigate KTP application possibilities for IR-to-THz and THz-to-THz wave conversion. As a result, phase matching for s − f → f and s − f → s types of difference frequency generation (DFG) of Ti:Sapphire laser (at the wavelengths of 0.65, 0.8 and 1.1 µm) is found possible, as well as second harmonic generation (SHG) of THz waves by f + s→f type of interaction in the XZ principle plane of the crystal. Terahertz wave generation by phase-matched parametric processes in KTP demonstrates evident advantages in comparison with that of widely used MgO-doped LiNbO3 crystals.

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