## 1 Introduction  
Eyes play an important role in our life, not only in seeing objects of the environment, but also in reading books, watching films, or recognizing and discriminating objects and members [1]. The visual acuity of the eye is generally regarded as the most important factor for seeing objects. Objects can generally be better distinguished from each other or from their background if the luminance or color difference is large. Contrast describes the difference in appearance of two or more parts of a field seen simultaneously or successively, a metrics for luminance or color differences. Contrast sensitivity is the capacity of the eye to perceive this difference [2; 3]. Vision is created by the contrast sensitivity of the eye and the image processing of the brain [4; 5; 6].  
The effect of color vision on food and commercial product judgements is an important topic of international research [7; 8; 9; 10; 11; 12; 13; 14; 15]. As an example, the effect of background color and pattern that can be traced back to as contrast between chromaticities of the two defined visual area is observed in detail [16; 17; 18]. Another aspect of color vision in food industry is the effect of colors on sensory evaluation [15]. Requirements regarding the visual acuity and color vision of sensory assessors are detailed in standards [19; 20]. In the case of visual evaluation, preliminary testing for anomalous color vision (color-vision deficiency) is required. Even though there are different types of color-vision deficiencies, a common phenomenon is the reduced ability in chromatic discrimination and contrast sensitivity, compared to normal trichromats [21].  
Even understanding individual differences between normal trichromat observers can be important to provide a standardized evaluation process [22; 23]. With the involvement of anomalous trichromats, more significant difference may occur, justifying the need for further research.  
In international researches the most accepted and accurate method for identification of color-vision deficiency is the anomaloscope examination. However, there are many pseudoisochromatic methods applied in practice as well [24; 25; 26; 27; 28; 29]. During these examinations, observers have to find differences or parity in special patterns the temporal effect of chromatic adaptation should be considered also.  
Observation of observers' gazing behavior with eye tracking is a widely used method that can provide detailed analysis based on the wide range of measured parameters, such as the count or the duration of fixations or the decision time [30; 31; 32].  
Therefore, the aim of this research was to answer whether eye tracking can be a method for testing color-vision deficiency.  
The main question of this research was whether anomalous and normal trichromats can be distinguished based on eye movements under different conditions of luminance and chromatic contrast sensitivity. In line with this question measurement with pseudoisochromatic figures were set in order to detect temporal patterns related to the results of the tests. Our main research questions were as follows:  
1. Which statistical method is suitable to model the differences between the number of right answers of anomalous and normal trichromats?
2. Which of eye movement variables have significant effect on the parameters (image, success and subject) and their interactions?
3. Is there any significant difference between eye movement variables of normal and anomalous trichromats?
4. How does the survival time of anomalous and normal trichromats change in the case of achromatic and colored figures?