**2. Materials and Methods**

All of the observers had normal colour vision. A refractive correction lens was evaluated [3,24]. Currently, there is no consensus on which colour test is the most complete. It is recommended to use at least 2 tests to uncover more information about visual perception [25]; possible tests include Ishihara, Color Vision Testing Made Easy (CVTME), Farnsworth–Munsell 100-Hue and other similar tests [25]. In many experiments, multiple light sources were used, with a CCT different in K value at different Duv values. These represent the most common light sources used, for example, in Chinese museums [3]. The application of memory and preferred colours to colour rendition evaluation of white light sources is reviewed with Sanders, Judd's flattery index, Thornton's colour preference index and Smet's memory colour rendition index. Here, we evaluated the agreement of data on visual appreciation and perception of naturalness [26]. Referenced patient studies comply with the Helsinky statement.

The participants evaluated a room with objects chosen to cover a range of hue, saturation and lightness values to evaluate the subjective impressions of a light source's colour quality [27]. The interpretation of lighting conditions included naturalness, vividness or preference in two scenes illuminated with different SPDs (spectral power distributions) [28].

With any transformation, colours varied in many directions and there was with no guarantee that colours fell within in the desired range [29]. In other experiments, the observer matched the left eye standard square with the luminance and chromaticity of the right eye modified by a control after being previously dark adapted [30]. The values were noted after the observer expressed that they were satisfied with the match by pressing a key [31]. The CVTME test consists of 10 plates for demonstration containing a circle, star and square, visible to all colour-deficient and colour-normal subjects and other plates designed for young children and those with learning difficulties [32,33].

Accommodation and vergence, in conjunction with ocular surface and blink, were evaluated while the participants were reading a text on a smartphone for a large time and were measured during reading. Eye fatigue and other symptoms, fixation disparity and binocular accommodation were assessed, and the frequency and amplitude of the blink and viewing distance were measured [19].

Accommodative lag and accommodative fluctuations were evaluated with the Grand Seiko WAM-5500 open-field auto-refractor [20]. Subjective DOFi was measured using a motorised Badal system. The subject's eye was paralysed and different, previously measured accommodative states were simulated with a deformable mirror. Different colour conditions were tested [21]. Spherical IOLs with different diopters were implanted in a IOL eye model and measured with a modulation transfer function (MTF) [22].
