Why Don’t Yellow Night Vision Glasses Work?

Abstract

Over the years, two things have happened that make night driving increasingly difficult for me: I have grown old and automobile headlights have grown whiter and brighter. With the transition from kerosene carriage lamps to sealed beam incandescent and, more recently, high-intensity discharge and light-emitting diode (LED) headlamps, the color and brightness of headlights have gradually evolved from a pleasant and romantic yellow candlelight to a light as harsh, glaring, and painful as the sun is to me. So, if I want to return to the good old days, what better solution could there be then to wear yellow-lensed glasses, which should make all headlights appear to be a nostalgic 2400°K color temperature.In this issue of JAMA Ophthalmology in a study using a driving simulator that would be coveted by players of Grand Theft Auto (Rockstar Games), Hwang et al 1 address the question of whether yellow glasses promoted as night-driving aids actually help drivers, young and old, deal with headlight glare. The computer-generated view through the windows of the simulated vehicle is panoramically displayed on five 42-in flat panel video screens arranged in a 225°arc that is 37°high. A real steering wheel, accelerator and brake pedals, shift stick, rear-view mirror, and instrument panel that interact with the computer, as well as a driver's seat, complete the virtual driving experience. The liquid crystal display video screens have a limited range of luminances that can be displayed, so Hwang et al invented a headlight glare simulator that optically superimposes dynamic images of oncoming headlights onto the video images. 2 The headlight images are generated by LEDs and are the correct luminance, color, and angular distribution of the light synchronized by the computer, with the virtual approaching vehicle producing realistic headlight glare sources. Nightdriving conditions were simulated with oncoming cars providing the headlight glare. The behavior measured in the study was the driver's ability to detect a pedestrian along the side of the road, or carelessly attempting to cross the road, with and without headlight glare. Unlike in Grand Theft Auto, in which colliding with the pedestrian would be considered a minor infraction, in the Hwang et al study, 1 the driver more humanely honked the horn to signal his or her detection of the pedestrian. In some cases, the pedestrian was wearing dark clothing (blue jeans and navy blue shirt) and in other cases the pedestrian was wearing an orange Hawaiian shirt instead (undoubtedly deferring to the well-known fashion preferences of one of the authors [E.P.]).The headlight glare had an association with the amount of time it took young participants to detect the pedestrians wearing dark clothing; the association was in the same direction, but not necessarily as strong, for young participants detecting pedestrians wearing the orange shirt. The older participants were tested only with the pedestrians wearing orange

The Invisibility of Scotomas I: The Carving Hypothesis

“…The distortion reported by patients with disciform AMD and illustrated here has been interpreted by Massof 9 to suggest a perceptual closure of visual space around the scotoma analogous to the closure of a drawstring bag. This drawstring closure hypothesis is similar but not identical to our scotoma carving.…”

“…In particular, the cause and nature of the distortions outside the scotoma are different in nature in these two cases. The reports of these spatial distortions surrounding AMD central scotomas led to the design of field remapping vision aids using counter distortions 9,69–72 . These authors proposed that the distortion introduced around the scotomas may be fully or largely compensated by a remapping image processing.…”

“…Smooth pursuit eye movements require tracking a moving object, which is not the situation shown in most of these videos, except for our simulation of vision with central scotoma 35 that included some smooth movement of the scotoma within the scene and the video frame. 36 In a Public Broadcast Service television program, featuring a low-vision device based on an early head-mounted display, 9 the simulations also showed smooth movement of the scotoma either at the center of the frame or within the frame; however, the eye movements measured and shown in the same program were all saccades, yet these were not simulated. Tracking a smoothly moving object using peripheral vision is not easy.…”

“…IOVS 1991;32:ARVO Abstract 816) 4–8 . Such distortions were illustrated in one simulation of central scotoma 9 and are addressed in this paper.…”

The effect of blue-light-blocking lenses on retinal straylight

“…Increased levels of retinal straylight in the eye cause drivers to experience disability glare, which can be particularly problematic when driving at night (Van den Berg et al 2009). Some researchers have suggested that yellow-tinted lenses can reduce disability glare (Hammond et al 2009;Massof 2019). This hypothesis is often based on the assumption that the human eye is affected by Rayleigh-type light scattering, in which short-wavelength light is scattered more than medium-and long-wavelength lights.…”