The effect of blue-blocking lenses on photostress recovery times for low and high contrast chromatic and achromatic stimuli

Abstract

1 2 3 4 The effect of blue-blocking lenses on photostress 5 recovery times for low and high contrast 6 chromatic and achromatic stimuli 7 8 9 Hind Abstract 24The selective reduction in visible wavelengths transmitted through commercially available 25 blue-blocking lenses (BBLs) is known to influence the appearance and contrast detection of 26 objects, particularly at low light levels which may impact the human retinal receptor response time 27 to dynamic light changes during phostress events. In the present study, we assessed whether BBLs 28 selectively affect photostress recovery times (PSRTs) in 12 participants for chromatic and 29 achromatic stimuli presented under low and high contrast luminance conditions. Four types of 30 commercially available BBLs were evaluated, and their effects on PSRTs were investigated. Our 31 results showed that PSRTs required to detect high contrast chromatic and achromatic stimuli were 32 unaffected by BBLs when compared to a clear control lens. However, PSRTs were significantly 33 affected by BBLs and were longer when chromatic and achromatic stimuli were of low contrast. In 34 addition, BBLs had the greatest impact on the PSRTs of blue coloured targets, and this was 35 dependent on the spectral transmittance profile. These results indicate that wearing BBLs under 36 low contrast conditions can have serious implications for visual behavior, particularly under low-37 light levels and in situations in which the observer is directly exposed to bright light sources. For 38 example, during night time driving, the driver might be briefly exposed to bright lights by glancing 39 at the headlights of a passing car. This increases the time required for vision to be restored after 40 bright light exposure, resulting in delayed object detection, and therefore stoppage and reaction 41 times, which might pose a safety risk for a driver. 42 43 Introduction 44 Blue-blocking lenses (BBLs), particularly so-called yellow BBLs with cutoff wavelengths 45 between 450 nm and 512 nm, have been designed to provide protection against hazardous blue light 46 [1]. These yellow BBLs have become popular in recent years and are used to aid vision in tasks such 47 as shooting [2], skiing, aviation [3], hunting and sailing [4]. It has been suggested that BBLs benefit 3 48 vision with reported improvement in visual tasks such as visual acuity [5, 6] particularly enhancing 49 the clarity of vision [7], and decreased glare [5, 8]. However, at present, the benefit of BBLs have 50 yet to be fully verified by empirical and independent evidence [9]. 51 Despite the potential benefits of BBLs, previous studies have shown that BBLs may impair 52 vision, particularly affecting the ability of the visual system to detect contrast under different visual 53 conditions [5, 10-12]. For example, Thomas et al. have shown that while BBLs do not affect 54 sensitivity to high-contrast photopic stimuli, detection of low-contrast mesopic stimuli is impaired 55 by BBLs [5]. BBLs also dramatically reduce contrast sensitivity under scotop...