ILAV   21219
INSTITUTO DE INVESTIGACION EN LUZ, AMBIENTE Y VISION
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Influence of age on contrast threshold detection for urban lamps with different spectral distribution in the mesopic range
Autor/es:
ARRANZ, ISABEL; MATESANZ, BEATRIZ MARIA; ISSOLIO LUIS A.; SILVA, BÁRBARA; COLOMBO ELISA MARGARITA; MENENDEZ, J A; MAR, SANTIAGO; APARICIO, JUAN ANTONIO
Lugar:
Tohoku University, Sendai Japan
Reunión:
Simposio; The 23rd Symposium of the International Colour Vision Society; 2015
Institución organizadora:
ICVS2015 Organizing Committee / Tohoku University
Resumen:
The streetlamps employed at nigh lighting conditions produce luminance levels within the mesopic range. Usually, the visual performance in these conditions is analysed by using models for mesopic spectral sensitivity that consider different factors such as the luminance and the chromaticity of thevisual scene, the retinal location and the type of illuminant. However, all these models have been developed from measurements performed on young subjects. In this study, we have analysed the effect of age and type of illuminant on the achromatic contrast detection thresholds. Measurements have been performed with a double Maxwellian view optical system. Three age groups, young, mid-age and old and two different light sources (metal halide MH, S/P = 1.17), and high pressure sodium HPS, S/P = 0.48), two retinal locations (fovea and 10º), and four background luminances (Lb = 0.01, 0.07, 0.45, and 3.4 cd/mIn eccentric vision and Lb = 0.01 cd/m2, contrast sensitivity was higher with HPS than MH in old-age subjects, while this situation is opposite to young subjects. In these conditions, adaptation and detection are governed by rods. In young subjects, the higher spectral sensitivity of rods to shorter wavelengths produces lower contrast detection thresholds for MH lamps than for HPS lamps. Opposite, in the old age group, the increase in the straylight due to theprereceptoral media aging produces an important increment in contrast detection threshold. This increment is particularly observed at very low Lb where rods are very sensitive; while at higher Lb, the effect is not so significant since detection is mostly due to cones. The directional sensitivity of thesemakes them less sensitive to intraocular scattering. We can conclude that the influence of age on contrast detection thresholds seems to be different for the two compared lamps type within the mesopic range. Therefore, the age should be included as a parameter in mesopic vision models.