Masatsugu KANAZAWA¹ and Hiroshi UOZATO^1,2

¹Department of Visual Science, Kitasato University Graduate School of Medical Sciences, Sagamihara 252-0373, Japan
²Department of Orthoptics and Visual Science, Kitasato University School of Allied Health Sciences, Sagamihara 252-0373, Japan

(Received October 2, 2012; Revised February 16, 2013; Accepted March 21, 2013)

We investigated the effect of absorptive lenses on contrast sensitivity under photopic- and mesopic-visions with glare, from the viewpoint of luminous transmittance (LT) and spectral transmittance. The subjects were 24 healthy volunteers. Log contrast sensitivity (logCS) under two luminance conditions with glare was measured with a contrast glare test device. Binocular logCSs with absorptive lenses were compared with those without absorptive lenses (control condition). Furthermore, to investigate the effect of spectral transmittance, we calculated the ratio of stimulus quantity and the correlation between this ratio and logCS. Compared with that in the control, logCS was hardly affected in the case of high-luminous-transmittance absorptive lenses under binocular visions with glare. Middle- and long-wavelength lights effectively contribute to contrast sensitivity under photopic-vision and lights at each wavelength showed almost the same coefficients of correlation under mesopic-vision. Previous studies suggested that absorptive lenses provide users with protection against harmful radiation and glare. Our present results suggested that short-wavelength and high-LT absorptive lenses are particularly useful in daylight.

Key words: absorptive lenses, contrast sensitivity, glare, luminous transmittance, spectral transmittance