Age-Dependent Impacts of Lighting Conditions on Contrast Sensitivity and Subjective Visual Perception Focusing on Pupil Size and Crystalline Lens Transmittance

The effects of different illuminances and correlated color temperatures (CCTs) of LED lighting on contrast sensitivity (log CS) and subjective visual perception (brightness and comfort) were compared in healthy children (<i>n</i> = 10, 9.9   ±   1.6 years old), middle-aged (<i>n</i> = 10, 40.7   ±   3.3 years) and older adults (<i>n</i> = 10, 68.3   ±   3.2 years). The six lighting conditions used were a combination of three illuminances (100, 300, and 750 lx) and two CCTs (3000 and 6000 K). Furthermore, we measured spectral crystalline lens transmittance and pupil size, and investigated relationships between visual-related measurements and ophthalmologic characteristics. Log CS significantly decreased in older adults and increased with increasing illuminance, regardless of age group or CCT. Multiple regression analysis revealed that age-related changes in log CS are not due to pupil size (<i>β</i> = 1.1  ×  10⁻³, <i>p</i> = .42) or age (<i>β</i> = 6.0  ×  10⁻⁴, <i>p</i> = .24) but are influenced by a decrease in lens transmittance (<i>β</i> = 1.72, <i>p</i> &lt; .0001). Subjective brightness and comfort increased with increasing illuminance, but comfort in children was not affected by illuminance and was a higher tendency at low CCT. These results show that the effects of the lighting environment, i.e. illuminance and CCT, on visual functions vary with age and ophthalmologic characteristics, especially crystalline lens transmittance, emphasizing the importance of designing a lighting environment considering these factors.