In response to a perceived need in the vision community, an OSA taskforce was formed at the 1999 topical meeting on vision science and its applications (VSIA-99) and charged with developing consensus recommendations on definitions, conventions, and standards for reporting of optical aberrations of human eyes. Progress reports were presented at the 1999 OSA annual meeting and at VSIA-2000 by the chairs of three taskforce subcommittees on (1) reference axes, (2) describing functions, and (3) model eyes.

Standards for reporting the optical aberrations of eyes

Purpose
Ocular trauma is a major cause of visual loss, but little is known about its epidemiology and clinical characteristics in China. The aim of this study was to determine the prevalence and clinical characteristics of ocular trauma and assess prognostic factors in Changsha, Hunan, located in South-Central China.

Methods
A retrospective case series (ICD codes: S05) study of ocular trauma in patients was performed at the Second Xiangya Hospital, Central South University, from 1 January 2010 to 31 December 2014. Demographic information, injury causes, ocular trauma types and initial and final visual acuity (VA) were recorded and analysed. The ocular trauma score (OTS) was calculated to assess the extent of the eye injury, prognosis and factors associated with visual impairment. All patient data were collected from the medical records system.

Results
Of the 2009 patients presenting during this 5-year period, 1695 (84.4%) were males and 314 (15.6%) were females. The average age of all patients was 37.0 ± 19.3 years (range from 1 to 87 years). The age distribution showed a peak in the ocular trauma population in the 41- to 50-year age group (24%, n = 482), followed by the 51- to 60-year age group (16.9%, n = 339). Overall, open-globe injuries had a higher frequency (70.7%, n = 1420) than closed-globe injuries (28.6%, n = 575) and thermal/chemical injuries (0.7%, n = 14). Of the open-globe injuries, corneal penetration was the most common injury (32.2%, n = 646) followed by rupture (21.5%, n = 432) and an intraocular foreign body (16.2%, n = 325). Overall, the most frequent ocular trauma setting was the workplace (39.6%, n = 795), followed by the home (28.4%, n = 570), and the most frequent activity was ironwork. Firecracker- and firework-associated ocular trauma was significantly higher during the months of January and February than during other months (50.0%, n = 112, p < 0.001). In patients under 18 years, the most frequently occurring injury was open globe (84.5%, n = 349) with corneal penetration (59.3%, n = 245). Overall, an operation was performed in 1865 (92.8%) cases, and 144 cases (7.2%) were treated conservatively with medication. The average OTS score was 47.1 ± 19.5. The visual prognosis was closely correlated with the initial VA (r = 0.570, p = 0.000) and the OTS score (r = 0.603, p = 0.000).

Conclusion
This study describes the epidemiology and clinical characteristics of patients hospitalized for ocular trauma in South-Central China. Notably, a high rate of firework-related ocular trauma occurred during the months adjacent to the Chinese New Year festival. Specific injury prevention strategies, such as the use of protective eyewear, need to target the workplace to reduce the incidence and severity of ocular trauma.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/aos.13438

Epidemiology and clinical characteristics of patients hospitalized for ocular trauma in South-Central China.

A pure adaptive interferometer is proposed for optical free form surfaces metrology without auxiliary devices such as the wavefont sensors and deflectometry systems for DM monitoring. In this method, the DM surface monitoring and free form surface measurement are achieved simultaneously in only one interferometer. The polarizing optics divide the interferometer into two partial common path interferometric system, which provide the null test for tested free form surface and non-null test for the DM surface. The final figure error of the free form surface is extracted by ray tracing. Experiments proving the feasibility of this interferometer is shown.

Pure adaptive interferometer for free form surfaces metrology

As the average corneal shape can effectively be approximated by a conic section, a determination of the corneal shape by biconic parameters is desired. The purpose of the paper is to introduce a straightforward mathematical approach for extracting clinically relevant parameters of corneal surface, such as radii of curvature and conic constants for principle meridians and astigmatism. A general description for modeling the ocular surfaces in a biconic form is given, based on which an implicit parametric surface fitting algorithm is introduced. The solution of the biconic fitting is obtained by a two sequential least squares optimization approach with constrains. The data input can be raw information from any corneal topographer with not necessarily a uniform data distribution. Various simulated and clinical data are studied including surfaces with rotationally symmetric and non-symmetric geometries. The clinical data was obtained from the Pentacam (Oculus) for the patient having undergone a refractive surgery. A sub-micrometer fitting accuracy was obtained for all simulated surfaces: 0,08 μm RMS fitting error at max for rotationally symmetric and 0,125 μm for non-symmetric surfaces. The astigmatism was recovered in a sub-minutes resolution. The equality in rotational symmetric and the superiority in non-symmetric surfaces of the presented model over the widely used quadric fitting model is shown. The introduced biconic surface fitting algorithm is able to recover the apical radii of curvature and conic constants in principle meridians. This methodology could be a platform for advanced IOL calculations and enhanced contact lens fitting.

Parametric fitting of corneal height data to a biconic surface.

Manufacturing spherical, aspheric, and freeform surfaces requires testing throughout the development and production process. State-of-the-art topography measurement is limited in applicability for intraocular lenses (IOLs), and there is no dedicated commercial surface measurement system available for freeform IOLs. The purpose of this work was to validate a deflectometric setup for surface measurement, detection of defects, and shape fidelity analysis for the development and production of IOLs. The setup is based on a phase measuring deflectometer with a field-of-view of 80 mm×80 mm and a mean repetition accuracy of 1.6·10(-3) D. The technique is suitable for detection of global and local surface errors, extracted from geometry and topography analysis. For validation according to DIN ISO 5725:2002, spherical IOLs with radii of curvature of 10 and 20 mm, a commercial aspheric IOL, and single-sided freeform IOL samples were used.

Inspection of freeform intraocular lens topography by phase measuring deflectometric methods.

Introduction Protectional eyewear has to fulfill both mechanical and optical stress tests. To pass those optical tests the surfaces of safety spectacles have to be optimized to minimize optical aberrations. Material and Methods Starting with the surface data of three measured safety spectacles, a theoretical spectacle model (four spherical surfaces) is recalculated first and then optimized while keeping the front surface unchanged. Next to spherical power, astigmatic power and prism imbalance we used the wavefront error (five different viewing directions) to simulate the optical performance and to optimize the safety spectacle geometries. Results All surfaces were spherical (maximum global deviation ‘peak-to-valley’ between the measured surface and the best-fit sphere: 0.132 mm). Except the spherical power of the model Axcont (−0.07 m −1 ) all simulated optical performance before optimization was better than the limits defined by standards. The optimization reduced the wavefront error by 1% to 0.150 λ (Windor/Infield), by 63% to 0.194 λ (Axcont/Bolle) and by 55% to 0.199 λ (2720/3 M) without dropping below the measured thickness. Conclusion The simulated optical performance of spectacle designs could be improved when using a smart optimization. A good optical design counteracts degradation by parameter variation throughout the manufacturing process.

Theoretical model for design and analysis of protectional eyewear.

Several activities in the occupational environment or in leisure time implicate an increased risk of eye injuries. Many injuries could be prevented by wearing adequate eye protection devices; however, the selection of appropriate eye protection devices requires considerations of different attributes in order to achieve a maximum of protection efficiency. This article provides an overview on the three basic types of eye protection device, introduces the classification regarding optical and protective properties and gives some additional advice on the selection of protective eyewear beyond the current standard regulations. Language: de

Protective glasses. Personal eye protection for professional use

Shack-Hartmann wave-front sensing has been successfully applied to many fields of optical testing including the human eye itself. We propose wave-front measurement for testing protective eye wear for production control and investigation of aberrations. Refractive power data is derived from the wave-front data and compared to a subjective measurement technique based on a focimeter. Additional image quality classification was performed with a multivariate model using objective parameters to resample a subjectively determined visual quality. Wave-front measurement advances optical testing of protective eye wear and may be used for objective quality control.

Wave-front analysis of personal eye protection

INTRODUCTION: Work in hazardous zones with the risk of mechanical injuries requires protection with safety spectacles. Mechanical eye injuries with metal foreign bodies are often caused by rotational material machining or production processes with high pressure or high velocity moving parts. Normative regulations restrict to tests with small and fast flying objects (e.g. 6mm ball). The literature does not provide any information about protection capabilities against larger objects with high mass and arbitrary shape. The purpose of this study was to test the protection efficiency of safety spectacles against flying objects. The scope of this paper is to present a new test setup for mechanical impact resistance testing of personal protective eyewear against objects with arbitrary shape and mass. MATERIAL AND METHODS: The setup is based on a catapult platform, accelerating a sliding carriage on a rail. A pull rope system allows velocities up to 62±2 m·s(-1). A photo sensor was used for velocity measurement. The carriage can be loaded with projectiles of up to 30mm×30mm×40mm in size with arbitrary orientation, depending on the carriage insert. Testing and validation was done with projectiles such as 7g metal chips and fragments with approximate dimensions of 10mm×15mm. Samples were standard occupational safety spectacles mounted on a test head. The projectile impact was captured with a monochrome high speed camera. RESULTS: The aiming accuracy test showed deviations of approximately 1mm of two impacts on the same spectacle surface with a free flight distance of 150mm. All tests with slow, medium and high speed projectiles showed no contact with the eye medium. Objects with velocities from 10 m·s(-1) to 62 m·s(-1) fired the spectacle off from the test head. The medium speed test cut off one side of the spectacle frame. The high speed test with 62±2 m·s(-1) cracked the polycarbonate shield. DISCUSSION: We describe a method for accelerating arbitrary objects up to 62 m·s(-1) and for aiming these objects on safety eyewear, mounted on a test head. The setup allows a variety of projectile shapes, orientations and velocities. The accuracy of velocity measurement is ± 2 m·s(-1) for high velocity ( Language: en

Experimental assessment of eye protection efficiency against high speed projectiles.

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