Recommendations and requirements for the wavelengths in Rayleigh equation anomaloscopes

DIN 6160:2019 is a technical standard that sets requirements for Rayleigh equation anomaloscopes. Table 1 of the standard contains the limits for centroid wavelengths and spectral half power bandwidths (SHBW). The centroid limits are more restrictive than dominant wavelength recommendations. The SHBW limits have no known evidence base and are inconsistent between colors. The spectral characteristics of three commercial anomaloscopes brands were measured using a telespectroradiometer. Only the oculus instruments complied with DIN 6160 Table 1, but all the anomaloscopes complied with published recommendations. All complied with the DIN 6160 bandwidth requirements. This highlights the need to provide an evidence base for such requirements

Physical and visual evaluation of filters for direct observation of the sun and the international standard ISO 12312-2:2015

We investigated the compliance of 43 commercially available solar filters (eclipse glasses) with the ISO 12312-2:2015 standard by measuring their spectral transmittances (280–2000 nm) and calculating their luminous, solar ultraviolet A, ultraviolet B, and infrared (IR) transmittances. We also evaluated the filters for usability by observing the full midday Sun and rating the view on a seven-point balanced scale, from “far too dark, details seen only with great difficulty” to “far too light, uncomfortable to view the Sun.” The mean ratings of two observers, one experienced and one inexperienced in solar observing, differed by 0.28 (95% confidence interval of the mean = 0.26). The inexperienced observer tended to be less accepting of high transmittances. All 43 solar filters complied with the UV and IR requirements. Eighteen filters passed the luminous transmittance requirements, and 24 were borderline too light or too dark. Seven of the 15 solar filters with a luminous transmittance darker than the requirement were rated as acceptable. One filter that passed and another that was borderline too light were rated as too light or far too light. The ISO 12312-2 limits derive from welding filter standards and do not represent an appropriate evidence base for direct solar viewing. This work provides the evidence base for a maximum 0.0012% and a minimum 0.00004% luminous transmittance for solar filters. The results of this study also support the use of welding filters between shades 12 and 16. Lighter welding filters are more acceptable than solar filters of the same luminous transmittance

The specification of color limits in eye protection lenses for use when color-contingent clinical observations are made

Objective: To investigate if color limitations in eye and face protection standards are sufficient to avoid interfering significantly in color-contingent clinical decisions. If not, to propose what requirement will ensure appropriate products. Methods: Yellow-tinted eye protectors, blue-blocking lenses and lightly tinted filters were assessed for compliance with eye and face protection standards and their effect on the color rendering. Results: Yellow-tinted eye protectors and many tinted filters cause significant noncompliance with hospital lighting recommendations and standards; however general eye protection standards do not exclude these lenses. The standard for eye protection against intense light sources, in cosmetic and medical applications (ISO 12609-1), does exclude lenses identified as affecting clinical color-related decisions significantly. Conclusions: Any recommendation or standard for eye and face protection for persons making color- contingent clinical decisions must include the requirement of ISO 12909-1. Persons making color-contingent clinical decisions should be advised to use only untinted or neutral-colored lenses. Clinical Significance: This research is intended to advise writers of standards and recommendations on eye and face protection for use where color-contingent clinical decisions are made to ensure that the protector does not interfere with these decisions. It is also intended to advise on the selection of tints in their eye protection

A model for assessing the efficacy of colour vision aids

Optical filter aids are marketed which claim to improve colour discrimination in red-green colour vision defectives. An earlier model has been revised and used to assess 9 currently available aids. Spectral reflectances (400-700 nm) for 80 colours equally spaced in hue angle at four equally spaced saturations were synthesised from chromatically adjacent Munsell colours. Aid induced chromaticity changes for Protanomals and Deuteranomals were calculated. Five aids enhanced red-green discrimination significantly for Protanomals and six for Deuteranomals and one aid reduced it significantly for both defectives. Five aids enhanced blue-yellow discrimination in Protanomals and Deuteranomals for whom it is not needed

Impact of Gamification of Vision Tests on the User Experience

Objective: Gamification has been incorporated into vision tests and vision therapies in the expectation that it may increase the user experience and engagement with the task. The current study aimed to understand how gamification affects the user experience, specifically during the undertaking of psychophysical tasks designed to estimate vision thresholds (chromatic and achromatic contrast sensitivity). Methods: Three tablet computer-based games were developed with three levels of gaming elements. Game 1 was designed to be a simple clinical test (no gaming elements), game 2 was similar to game 1 but with added gaming elements (i.e., feedback, scores, and sounds), and game 3 was a complete game. Participants (N = 144, age: 9.9-42 years) played three games in random order. The user experience for each game was assessed using a Short Feedback Questionnaire. Results: The median (interquartile range) fun level for the three games was 2.5 (1.6), 3.9 (1.7), and 2.5 (2.8), respectively. Overall, participants reported greater fun level and higher preparedness to play the game again for game 2 than games 1 and 3 (P < 0.05). There were significant positive correlations observed between fun level and preparedness to play the game again for all the games (p < 0.05). Engagement (assessed as completion rates) did not differ between the games. Conclusion: Gamified version (game 2) was preferred to the other two versions. Over the short term, the careful application of gaming elements to vision tests was found to increase the fun level of users, without affecting engagement with the vision test

When is protection from impact needed for the face as well as the eyes in occupational environments?

Background: The most commonly identified reason for requiring or using occupational eye and face protection is for protection against flying objects. Standards vary on what risk may require protection of the eyes alone and what requires protection for the whole face. Information on the minimum energy transfer for face damage to occur is not well-established. Methods: The heads of pigs were used as the common model for human skin. A 6 mm steel ball projected at velocities between 45 and 135 m/s was directed at the face area. Examples of impacts were filmed with a high-speed camera and the resulting damage was rated visually on a scale from 1 (no visible damage) to 5 (penetrated the skin and embedded in the flesh). Results: The results for the cheek area indicate that 85 m/s is the velocity above which damage is more likely to occur unless the skin near the lip is included. For damage to the lip area to be avoided, the velocity needs to be 60 m/s or less. Conclusion: The present data support a maximum impact velocity of 85 m/s, provided the thinner and more vulnerable skin of the lids and orbital adnexa is protected. If the coverage area does not extend to the orbital adnexa, then the absolute upper limit for the velocity is 60 m/s. At this stage, eye-only protection, as represented by the lowest level of impact test in the standards in the form of a drop ball test, is not in question

Normative values for a tablet computer-based application to assess chromatic contrast sensitivity

Tablet computer displays are amenable for the development of vision tests in a portable form. Assessing color vision using an easily accessible and portable test may help in the self-monitoring of vision-related changes in ocular/systemic conditions and assist in the early detection of disease processes. Tablet computer-based games were developed with different levels of gamification as a more portable option to assess chromatic contrast sensitivity. Game 1 was designed as a clinical version with no gaming elements. Game 2 was a gamified version of game 1 (added fun elements: feedback, scores, and sounds) and game 3 was a complete game with vision task nested within. The current study aimed to determine the normative values and evaluate repeatability of the tablet computer-based games in comparison with an established test, the Cambridge Colour Test (CCT) Trivector test. Normally sighted individuals [N = 100, median (range) age 19.0 years (18–56 years)] had their chromatic contrast sensitivity evaluated binocularly using the three games and the CCT. Games 1 and 2 and the CCT showed similar absolute thresholds and tolerance intervals, and game 3 had significantly lower values than games 1, 2, and the CCT, due to visual task differences. With the exception of game 3 for blue-yellow, the CCT and tablet computer-based games showed similar repeatability with comparable 95% limits of agreement. The custom-designed games are portable, rapid, and may find application in routine clinical practice, especially for testing younger populations

Difficult at dusk? Illuminating the debate on cricket ball visibility

Objectives: Investigate the visibility of new and old red, white and pink cricket balls under lighting and background conditions experienced during a day–night cricket match. Design: We modelled the luminance contrast signals available for a typical observer for a ball against backgrounds in a professional cricket ground, at different times of day. Methods: Spectral reflectance (light reflected as a function of wavelength) was derived from laboratory measurements of new and old red, white and pink balls. We also gathered spectral measurements from backgrounds (pitch, grass, sightscreens, crowd, sky) and spectral illuminance during a day–night match (natural afternoon light, through dusk to night under floodlights) from Lord's Cricket Ground (London, UK). The luminance contrast of the ball relative to the background was calculated for each combination of ball, time of day, and background surface. Results: Old red and old pink balls may offer little or no contrast against the grass, pitch and crowd. New pink balls can also be of low contrast against the crowd at dusk, as can pink and white balls (of any age) against the sky at dusk. Conclusions: Reports of difficulties with visibility of the pink ball are supported by our data. However, our modelling also shows that difficulties with visibility may also be expected under certain circumstances for red and white balls. The variable conditions in a cricket ground and the changing colour of an ageing ball make maintaining good visibility of the ball a challenge when playing day–night matches