## 4 Discussion  
This study examined changes in visual function, alertness, and cognitive performance in a sample of healthy young adults without pathologies following their adaptation to various lighting conditions. The participants were instructed to perform three computerized tests designed for this purpose. Additionally, optical changes in the visual system were investigated through aberrometric measurements conducted before (baseline) and after the completion of the tests under each of the different lighting conditions. In Test 1, under red ambient lighting conditions, poorer results were obtained across all VAs. This could be attributed not only to the direct effect of the lighting itself but also to the lower contrast between the white letters and the red background (0.66) compared to the contrast between white letters on a blue background (0.83) or black letters on a white background (0.98). These lower differences in contrast likely increased the difficulty in letter recognition. This observation also explains why the best results were achieved under white lighting, despite contradicting findings by [PERSON] et al. [32], who argued that background color did not significantly affect VA. However, [PERSON] and [PERSON] [33] suggested that the combination of background color relative to the stimulus had a profound effect on visual performance, which is consistent with our findings. These discrepancies could stem primarily from differences in ambient conditions and in the optotypes used in the experiments. Previous studies have also examined the relationships between VA in logMAR and white, blue, and red lighting conditions, as well as luminance levels [32; 34; 35; 36]. The experimental conditions described by these authors differ significantly from ours and among themselves, posing challenges for a comprehensive analysis. [PERSON] et al. [34; 35] reported higher VAs under white and red lighting conditions (VA \(-\)0.100 and VA \(-\)0.107, respectively), whereas worse results were obtained under blue lighting (VA 0.260), contrary to our findings. In [PERSON] et al. 's work [36], the difference between red and white lighting (VA \(-\)0.041 and VA \(-\)0.049) and blue lighting (VA 0.041) was much smaller. The discussion in these studies revolves around Longitudinal Chromatic Aberration (LCA), where subjects become myopic when measured on blue (resulting in poorer VA) and hyperopic when measured on red in the absence of accommodation. This phenomenon is based on the refractive index's dependence on wavelength--shorter wavelengths correspond to higher refractive indices and vice versa and could explain these findings. However, upon examining the aberrometric measurement data (Figure 8), our results did not reveal significant differences in the coefficients of order 2 (Table 2) or in M and J0 between blue and red lighting conditions, suggesting that the effect of the LCA would be minimal. Consequently, LCA may not be the primary cause of the decreased VA or test accuracy in our study. These findings are consistent with studies that have measured VA with and without LCA correction [37; 38; 39; 40], where improvements were not achieved under high-contrast conditions or with adaptation time for correction. A slight decrease in VA values was observed when the LCA was doubled [39]. In contrast, [PERSON] et al. [40] reported a difference in VA, but only when both the LCA and transverse chromatic aberration (TCA) were corrected simultaneously. Other factors that could contribute to the differences among these studies include the use of different VA measurement methods and varying room lighting conditions. Additionally, in the mentioned studies [34; 35], the subjects were not adapted to ambient lighting, and the illuminance reaching the corneal plane under different lighting conditionswas not specified. Moreover, the luminance levels and contrasts evaluated in those studies differ from ours, which directly affects VA outcomes [7].