Performance analysis of a compact auto-phoropter for accessible refractive assessment of the human eye.

We present the performance analysis and specifications of a portable auto-phoropter system that can be employed for fast refractive assessment of a large population. A customized Shack-Hartmann wavefront sensor is developed to accurately measure the defocus and astigmatism of the eye within ±10 and ±6, respectively. Three fluidic lenses are designed to correct the vision in real time.

New methodology for measuring intraocular lens performance using acuity reserve.

Purpose: To validate a new methodology of intraocular lens (IOL) assessment using acuity reserve analysis via area under the curve (AUC) to assess intermediate vision.

Setting: Study 1 was conducted at 17 sites in Australia, Chile, and Europe. Study 2 was conducted at 15 sites in Australia, Brazil, and Europe.

Relating wavefront error to visual acuity in pre- and post-LASIK eyes: a comparison of methods.

Contrast threshold and visual Strehl ratio methods are used to predict visual acuity from wavefront error for a sample population of pre- and post-LASIK patients. Relative error (in logMAR) between predicted and measured visual acuity values are computed for each method and compared using paired t-tests. Differences in aberration data between pre- and post-LASIK eyes are then evaluated.

Corneal aberrations measured with a high-resolution Scheimpflug tomographer: repeatability and reproducibility.

Purpose: To evaluate the precision of elevation and wavefront aberration measurements with the Pentacam HR (Oculus Optikgeräte GmbH).

Setting: Flinders University, Australia.

Design: Instrument evaluation study.

Goldmann tonometry tear film error and partial correction with a shaped applanation surface.

Purpose: The aim of the study was to quantify the isolated tear film adhesion error in a Goldmann applanation tonometer (GAT) prism and in a correcting applanation tonometry surface (CATS) prism.

Methods: The separation force of a tonometer prism adhered by a tear film to a simulated cornea was measured to quantify an isolated tear film adhesion force. Acrylic hemispheres (7.

Goldmann and error correcting tonometry prisms compared to intracameral pressure.

Background: Compare Goldmann applanation tonometer (GAT) prism and correcting applanation tonometry surface (CATS) prism to intracameral intraocular pressure (IOP), in vivo and in vitro.

Methods: Pressure transducer intracameral IOP was measured on fifty-eight (58) eyes undergoing cataract surgery and the IOP was modulated manometrically to 10, 20, and 40 mmHg. Simultaneously, IOP was measured using a Perkins tonometer with a standard GAT prism and a CATS prism at each of the intracameral pressures.

Goldmann applanation tonometry error relative to true intracameral intraocular pressure in vitro and in vivo.

Background: Goldmann applanation tonometry (GAT) error relative to intracameral intraocular pressure (IOP) has not been examined comparatively in both human cadaver eyes and in live human eyes. Futhermore, correlations to biomechanical corneal properties and positional changes have not been examined directly to intracameral IOP and GAT IOP.

Methods: Intracameral IOP was measured via pressure transducer on fifty-eight (58) eyes undergoing cataract surgery and the IOP was modulated manometrically on each patient alternately to 10, 20, and 40 mmHg.

A new low-cost, compact, auto-phoropter for refractive assessment in developing countries.

Using a phoropter to measure the refractive error is one of the most commonly used methods by ophthalmologists and optometrists. Here, we demonstrate design and fabrication of a portable automatic phoropter with no need for patient's feedback. The system is based on three tunable-focus fluidic lenses and thin-film holographic optical elements to perform automatic refractive error measurement and provide a diagnostic prescription without supervision.

Comparison of vision through surface modulated and spatial light modulated multifocal optics.

Spatial-light-modulators (SLM) are increasingly used as active elements in adaptive optics (AO) systems to simulate optical corrections, in particular multifocal presbyopic corrections. In this study, we compared vision with lathe-manufactured multi-zone (2-4) multifocal, angularly and radially, segmented surfaces and through the same corrections simulated with a SLM in a custom-developed two-active-element AO visual simulator. We found that perceived visual quality measured through real manufactured surfaces and SLM-simulated phase maps corresponded highly.

Chalcogenide Hybrid Inorganic/Organic Polymers: Ultrahigh Refractive Index Polymers for Infrared Imaging.

We report on the preparation of ultrahigh refractive index polymers via the inverse vulcanization of elemental sulfur, selenium, and 1,3-diisopropenylbenzene for use as novel transmissive materials for mid-infrared (IR) imaging applications. Poly(sulfur--selenium--(1,3-diisopropenylbenzene)) (poly(S--Se--DIB) terpolymer materials from this process exhibit the highest refractive index of any synthetic polymer ( > 2.0) and excellent IR transparency, which can be directly tuned by terpolymer composition.

Goldmann tonometer error correcting prism: clinical evaluation.

Purpose: Clinically evaluate a modified applanating surface Goldmann tonometer prism designed to substantially negate errors due to patient variability in biomechanics.

Methods: A modified Goldmann prism with a correcting applanation tonometry surface (CATS) was mathematically optimized to minimize the intraocular pressure (IOP) measurement error due to patient variability in corneal thickness, stiffness, curvature, and tear film adhesion force. A comparative clinical study of 109 eyes measured IOP with CATS and Goldmann prisms.

Relating wavefront error, apodization, and the optical transfer function: general case.

In a previous paper, a technique was developed for decomposing the incoherent optical transfer function (OTF) into a linear combination of basis functions [J. Opt. Soc.

High Refractive Index Copolymers with Improved Thermomechanical Properties via the Inverse Vulcanization of Sulfur and 1,3,5-Triisopropenylbenzene.

The synthesis of a novel high sulfur content material possessing improved thermomechanical properties is reported via the inverse vulcanization of elemental sulfur (S) and 1,3,5-triisopropenylbenzene (TIB). A key feature of this system was the ability to afford highly cross-linked, thermosetting materials, where the use of TIB as a comonomer enabled facile control of the network structure and dramatically improved the glass transition temperature (relative to our earlier sulfur copolymers) of poly(sulfur-random-(1,3,5-triisopropenylbenzene)) (poly(S--TIB)) materials over a range from = 68 to 130 °C. This approach allowed for the incorporation of a high content of sulfur-sulfur (S-S) units in the copolymer that enabled thermomechanical scission of these dynamic covalent bonds and thermal reprocessing of the material, which we confirmed via dynamic rheological characterization.

Goldmann Tonometer Prism with an Optimized Error Correcting Applanation Surface.

Purpose: We evaluate solutions for an applanating surface modification to the Goldmann tonometer prism, which substantially negates the errors due to patient variability in biomechanics.

Methods: A modified Goldmann or correcting applanation tonometry surface (CATS) prism is presented which was optimized to minimize the intraocular pressure (IOP) error due to corneal thickness, stiffness, curvature, and tear film. Mathematical modeling with finite element analysis (FEA) and manometric IOP referenced cadaver eyes were used to optimize and validate the design.

Relating wavefront error, apodization, and the optical transfer function: on-axis case: reply.

Efficient coding enables rapid calculation of basis functions for a linear expansion of the optical transfer function.

Effects of Intraocular Lens Opacification on Light Scatter, Stray Light, and Overall Optical Quality/Performance.

Purpose: To evaluate light scatter and stray light in intraocular lenses (IOLs) explanted because of postoperative opacification (13 calcified hydrophilic acrylic, 1 calcified silicone, and 4 polymethylmethacrylate [PMMA] lenses with snowflake degeneration), as well as effect of opacification on other optical quality/performance indicators, in comparison with controls.

Methods: The Complete Angle Scatter Instrument (CASI) scatterometer was used to measure the forward light scattering (FLS) of the IOLs, and the stray light values at various angles were calculated from the measured FLS. Modulation transfer function (MTF) was obtained with an optical bench, and a Badal optometer was used to obtain letter chart images through the lenses.

Light scattering, straylight, and optical quality in hydrophobic acrylic intraocular lenses with subsurface nanoglistenings.

Purpose: To evaluate forward light scattering and straylight in single-piece hydrophobic acrylic intraocular lenses (IOLs) (Acrysof) removed from cadaver eyes and design- and power-matched controls, as well as the effect of subsurface nanoglistenings on other optical quality and performance indicators.

Setting: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA.

Range of refractive independence and mechanism of action of a corneal shape-changing hydrogel inlay: results and theory.

Purpose: To demonstrate the independence of visual performance over a range of preoperative refraction and age in presbyopes implanted with a corneal shape-changing inlay (Raindrop Near Vision Inlay).

Setting: Two multispecialty clinics, Monterrey and Tijuana, Mexico.

Design: Prospective case series.

Higher-order aberrations and best-corrected visual acuity in Native American children with a high prevalence of astigmatism.

Purpose: To determine whether higher-order aberrations (HOAs) in children from a highly astigmatic population differ from population norms and whether HOAs are associated with astigmatism and reduced best-corrected visual acuity.

Methods: Subjects were 218 Tohono O'odham Native American children 5-9 years of age. Noncycloplegic HOA measurements were obtained with a handheld Shack-Hartmann sensor (SHS).

Snapshot retinal imaging Mueller matrix polarimeter.

Early diagnosis of glaucoma, which is a leading cause for visual impairment, is critical for successful treatment. It has been shown that Imaging polarimetry has advantages in early detection of structural changes in the retina. Here, we theoretically and experimentally present a snapshot Mueller Matrix Polarimeter fundus camera, which has the potential to record the polarization-altering characteristics of retina with a single snapshot.

Deformable Surface Accommodating Intraocular Lens: Second Generation Prototype Design Methodology and Testing.

Purpose: Present an analysis methodology for developing and evaluating accommodating intraocular lenses incorporating a deformable interface.

Methods: The next generation design of extruded gel interface intraocular lens is presented. A prototype based upon similar previously in vivo proven design was tested with measurements of actuation force, lens power, interface contour, optical transfer function, and visual Strehl ratio.

Relating wavefront error, apodization, and the optical transfer function: on-axis case.

The incoherent optical transfer function (OTF) describes contrast degradation and phase shifts of sinusoidal objects of all spatial frequencies and orientations. The OTF is calculated as either an autocorrelation of the pupil function or the Fourier transform of the point spread function. Even with fast algorithms, these calculations can be slow for a densely sampled pupil.

Visual aberrations in a multifocal intraocular lens with injection-related scratches.

Unlabelled: We describe the case of a 70-year-old woman who had phacoemulsification and implantation of a single-piece hydrophobic acrylic multifocal intraocular lens (IOL). Following surgery, the patient experienced blurring, positive dysphotopsia, impaired night vision, and glare. After 2 years, optic damage likely related to the IOL injection procedure was noted.

Utility of an open field Shack-Hartmann aberrometer for measurement of refractive error in infants and young children.

Purpose: To assess the utility of an open-field Shack-Hartmann aberrometer for measurement of refractive error without cycloplegia in infants and young children.

Method: Data included 2698 subject encounters with Native American infants and children aged 6 months to <8 years. We attempted right eye measurements without cycloplegia using the pediatric wavefront evaluator (PeWE) on all participants while they viewed near (50 cm) and distant (2 m) fixation targets.

Nonmechanical zoom system through pressure-controlled tunable fluidic lenses.

We have developed a variable-power zoom system that incorporates fluidic lenses and has no moving parts. The designed system applies two single-chamber plano-convex fluid singlets, each with their own distinct design, as well as a conventional refractive lens. In this paper, we combine the two fluid elements to form a variable-power telescope, while the fixed lens enables image formation.