Hazard Perception in Visually Impaired Drivers Who Use Bioptic Telescopes.

Purpose: Bioptic telescopic spectacles can allow individuals with central vision impairment to obtain or maintain driving privileges. The purpose of this study was to (1) compare hazard perception ability among bioptic drivers and traditionally licensed controls, (2) assess the impact of bioptic telescopic spectacles on hazard perception in drivers with vision impairment, and (3) analyze the relationships among vision and hazard detection in bioptic drivers.

Methods: Visual acuity, contrast sensitivity, and visual field were measured for each participant.

Vision, Driving Exposure, and Collisions in Bioptic Drivers.

Significance: Lack of knowledge regarding the mileage driven by drivers with low vision who use bioptic telescopes could obscure the relationship between vision and road safety. This study provides data suggesting that worse vision is correlated with less mileage driven but more collisions per mile in bioptic drivers.

Purpose: The purpose of this study was to determine whether vision or demographic factors predict mileage driven in bioptic drivers and per-mile motor vehicle collision rate and also to compare the collision rate of bioptic drivers with previous estimates for the general population.

Design, fabrication, and testing of a Shack-Hartmann sensor with an automatic registration feature.

In this research, design, construction, and testing of an innovative Shack-Hartmann sensor are described. As the most critical component, a polymer microlens array is injection molded and mounted on a board-level CMOS camera such that the focal plane of the microlens array is on the camera's image plane. To allow for automatic registration of the spots of the measured area, a diffusing surface was created at the center of the lens array in the same diamond machining process in an uninterrupted operation.

Previous Driving Experience, but Not Vision, Is Associated With Motor Vehicle Collision Rate in Bioptic Drivers.

Purpose: Bioptic telescopic spectacles (BTS) consist of a small telescope (or telescopes) mounted high in a pair of spectacle lenses. More than 40 states allow for some form of bioptic driving licensure for people with decreased central vision. The purpose of this study was to determine significant associations among previous driving experience, vision, and motor vehicle collisions (MVCs) for bioptic drivers in Ohio.

Vision, training hours, and road testing results in bioptic drivers.

Purpose: Bioptic telescopic spectacles can be used by people with central visual acuity that does not meet the state standards to obtain an unrestricted driver's license. The purpose of this study was to examine the relationships among visual and demographic factors, training hours, and the results of road testing for bioptic drivers.

Methods: A retrospective study of patients who received an initial daylight bioptic examination at the Ohio State University and subsequently received a bioptic license was conducted.

Fabrication of microinjection-molded miniature freeform Alvarez lenses.

Microinjection molding is a mass production method to fabricate affordable optical components. However, the intense nature of this process often results in part deformation and uneven refractive index distribution. These two factors limit the precision of replicated optics.

Propagation of aberrated wavefronts using a ray transfer matrix.

A ray transfer matrix is used to calculate the propagation of aberrated wavefronts across a homogeneous refractive index. The wavefront is represented by local surface normals, i.e.

Simulation and measurement of optical aberrations of injection molded progressive addition lenses.

Injection molding is an important mass-production tool in the optical industry. In this research our aim is to develop a process of combining ultraprecision diamond turning and injection molding to create a unique low-cost manufacturing process for progressive addition lenses (PALs). In industry, it is a well-known fact that refractive index variation and geometric deformation of injection molded lenses due to the rheological properties of polymers will distort their optical performance.

Comparison of progressive addition lenses by direct measurement of surface shape.

Purpose: To compare the optical properties of five state-of-the-art progressive addition lenses (PALs) by direct physical measurement of surface shape.

Methods: Five contemporary freeform PALs (Varilux Comfort Enhanced, Varilux Physio Enhanced, Hoya Lifestyle, Shamir Autograph, and Zeiss Individual) with plano distance power and a +2.00-diopter add were measured with a coordinate measuring machine.

Comparison of three techniques in measuring progressive addition lenses.

Purpose: To measure progressive addition lenses (PALs) by three techniques and to compare the differences across techniques.

Methods: Five contemporary PALs (Varilux Comfort Enhanced, Varilux Physio Enhanced, Hoya Lifestyle, Shamir Autograph, and Zeiss individual) with plano distance power and a +2.00 diopters (D) add were evaluated under the condition of lateral displacement of the lens (no rotation and no tilt) using three methods.

Aberrations and spherocylindrical powers within subapertures of freeform surfaces.

A method is described for the derivation of refractive properties and aberration structure of subapertures of freeform surfaces. Surface shapes are described in terms of Zernike polynomials. The method utilizes matrices to transform between Zernike and Taylor coefficients.

Evaluation of single pixel step sizes in visual acuity assessment.

Purpose: Adaptive thresholding procedures (e.g., ZEST) benefit from testing near the current estimate of threshold.

Whole-surface characterization of progressive addition lenses.

Purpose: To characterize and compare progressive addition lens (PAL) surfaces in terms of the Zernike polynomials.

Methods: We examine the spherocylindrical characteristics of PALs by performing a physical surface height measurement of three lenses. Surface shape is described as the sum of Zernike polynomials.

Development of a battery of functional tests for low vision.

Purpose: We describe the development and evaluation of a battery of tests of functional visual performance of everyday tasks intended to be suitable for assessment of low vision patients.

Methods: The functional test battery comprises-Reading rate: reading aloud 20 unrelated words for each of four print sizes (8, 4, 2, & 1 M); Telephone book: finding a name and reading the telephone number; Medicine bottle label: reading the name and dosing; Utility bill: reading the due date and amount due; Cooking instructions: reading cooking time on a food package; Coin sorting: making a specified amount from coins placed on a table; Playing card recognition: identifying denomination and suit; and Face recognition: identifying expressions of printed, life-size faces at 1 and 3 m. All tests were timed except face and playing card recognition.

Interdisciplinary allied health education in treating older adults with low vision.

In 2000, the number of elderly citizens in the United States was 35 million, an increase of 3.7 million (11%) since 1990. Of these older adults, approximately 1.

Automated decision tree classification of corneal shape.

Purpose: The volume and complexity of data produced during videokeratography examinations present a challenge of interpretation. As a consequence, results are often analyzed qualitatively by subjective pattern recognition or reduced to comparisons of summary indices. We describe the application of decision tree induction, an automated machine learning classification method, to discriminate between normal and keratoconic corneal shapes in an objective and quantitative way.

Design and fabrication of a freeform phase plate for high-order ocular aberration correction.

In recent years it has become possible to measure and in some instances to correct the high-order aberrations of human eyes. We have investigated the correction of wavefront error of human eyes by using phase plates designed to compensate for that error. The wavefront aberrations of the four eyes of two subjects were experimentally determined, and compensating phase plates were machined with an ultraprecision diamond-turning machine equipped with four independent axes.

Corneal asphericity and apical curvature in children: a cross-sectional and longitudinal evaluation.

Purpose: The contour of the human cornea is closely modeled by a conic section, which is fully described by asphericity (Q) and apical radius of curvature (r(o)). The relationship between corneal shape and other ocular dimensions in children, including anterior and vitreous chamber depths, axial length, and spherical equivalent refractive error, was investigated.

Methods: Corneal asphericity and r(o) were calculated by using corneal topography data on 643 children (72 myopes, 370 emmetropes, and 201 hyperopes), ages 6 to 15 years, who participated in the Orinda Longitudinal Study of Myopia (OLSM) during 1991.

Repeatability of corneal topography measurement in keratoconus with the TMS-1.

Purpose: The purpose of this study was to report the test-retest variability of simulated indices derived from the TMS-1 topography instrument (Tomey Technology, Waltham, MA) in keratoconus subjects enrolled in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study.

Methods: Four images were taken at an initial visit and at a repeat visit several weeks later. From these images, 17 indices were simulated from published formulas.

Enhancing RGP contact lens performance: comparing back surface options.

Background: In some cases, rigid gas-permeable (RGP) contact lenses may be the best--or only--means of refractive correction. High Dk RGP materials have markedly reduced hypoxia under those lenses. With aspheric lens back surface designs, post-lens circulation may be enhanced as well by maximizing the provision of nutrients and the clearance of metabolic by-products, toxins, and debris, while minimizing the risk of lens binding.

Between-eye asymmetry in keratoconus.

Purpose: To report baseline differences between eyes on key variables in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study cohort compared with a retrospectively assembled group of myopic contact lens wearers without ocular disease.

Methods: A total of 1,079 keratoconus patients who had not undergone a penetrating keratoplasty in either eye before their baseline visit were enrolled and examined at baseline. Records from 330 contact lens-wearing myopes were reviewed.