| Color vision was an important part of visual function, it played an critical role in the civil aviation flight activities. Pilots relied on color signal to distinguish the position of the runway, identifying various colors of flight instruments in the cockpit, obstacles, traffic lights and so on. Pilots needed to depend on the color signal to recognize boundary lights, obstruction lights, navigation lights and signal flares when flying at night. Air traffic controllers also transmitted information with pilots by color signal, directing them to land or take off. Thus, the examination of color vision was vitally important for aeronautical work.The pseudo-isochromatic plate was widely used to inspect the color vision of airline staff in China, which was convenient and easy to use. But pseudo-isochromatic plate could not provide quantitative results about color vision and some applicants passed examination through previous contemporary memory. Furthermore, if the subject with color weak could identify the variety of color signals in aviation environment and fulfill aviation tasks safely, they shall be thought qualified according to the provisions of China's civil aviation medical examination. However, the provision lacked of specific and reasonable quantitative way to achieve it. Therefore, exploring a kind of qualitative and quantitative color vision method, which also made a judgment whether the people with color weak possessed the capacity to fulfill aviation task in securely, was imperative.This study designed a set of color vision inspection system of aviation staff. The color vision testing system was easy to use and carry, which also presented high efficiency and accuracy. Besides, the system made a quantitative judgment about whether color weak possessed the capacity to fulfill aviation task securely or not. Thus the color vision system supplemented color vision inspection methods and improved the level color vision testing of China's civil aviation.Part one: FM100 color vision testing systemObjectives: The study designed a FM100 color vision testing system and explored the validity of the system. The second step was to explore the cut off score to judge the test results about qualitative and quantitative of the system and finally to improve the efficiency and accuracy of color vision examination in China's civil aviation.Methods: Firstly, based on the principle of FM100 color vision instrument and simulated its testing environment to design FM100 color vision testing system. Secondly, starting experiment research of 218 subjects who were included in the study. The subjects were asked to finish the pseudo-isochromatic plates of Zi-ping Yu and Ishihara test at first. FM100 color vision test instrument and FM100 color vision testing system were followed at random after 5 minutes of free practice. The interval between each item was 15 minutes. Finally, Analyzing the difference of results between FM100 color vision testing system and FM100 color vision instrument by comparative study and establishing the threshold criteria of FM100 color vision testing system.Results: There were 159 cases with normal color vision and 59 cases with abnormal in this study. The testing results between FM100 color vision testing system and FM100 color vision equipment had no difference(19.84 ± 17.543 VS 19.40 ± 18.454; 160.51 ± 66.469 VS 150.73 ± 66.954, P> 0.05). But the testing time of the former was less than the latter(11.05 ± 2.972 VS 12.96 ± 3.054; 7.73 ± 2.490 VS 12.64 ± 3.284, P<0.05). The correlation coefficient R of the two methods was 0.885(P <0.001) and internal consistency coefficient(Cohen's Kappa) was 0.89. To analyze the results of FM100 color vision test system by qualitative and quantitative way, the scores were higher, the ability of color vision was worse. The cut-off score for superior versus average and poor color discrimination was 34(sensitivity 58.0%, specificity 94.7%) and for poor versus superior and average color discrimination was 101(sensitivity 98.0%, specificity 98.0%). The higher the score, the more severe of color vision deficiency. The cut off score of the normal and abnormal color vision was 72. The sensitivity and specificity were 96.6% and 98.7%, the color weak and color blindness was 110, the sensitivity and specificity were 97.6% and 97.7%.Conclusions: FM100 color vision testing system was easy to use and carry, which presented high validity and accuracy. The system also could judge the testing results by qualitative and quantitative analysis and achieved to improve the efficiency and level of color vision inspection in aviation staff.Part two: color vision testing system of aviation environmentObjectives: The second part was to design aviation environment color vision testing system and explore the validity of the system. Then establishing the evaluation criteria, which could recognize whether the applicants of color weak had the capability to meet the requirement of the aviation task by applying this system or not. The aim was to supplement and improve the method of color vision testing in China's civil aviation.Methods: Firstly, designing aviation environment color vision test system(including airport, cabin and radar testing system) according to the standard of aviation personnel color vision test. Secondly, 140 subjects were included in the study. The subjects were asked to finish the pseudo-isochromatic plate of Zi-ping Yu and Ishihara test at first. Then to complete the airport, the cabin and the radar testing system at random after 5 minutes of free practice. The interval between each project was 15 minutes. Finally, analyzing the effectiveness of aviation environmental color vision testing system and establishing the threshold criteria, which could judge whether pilots and air traffic controllers of color weak could executive aviation tasks or not.Results: There were 80 cases of normal color vision, 17 of color weak and 43 of color blindness. The score of the three color vision testing systems(including) were in descending trend from normal color vision to color blindness and color weak group. Results of the pilot environment color vision testing system(including airport and cabin testing system) and air traffic administrator environment color vision testing system(including airport and radar testing system) showed that the score between the normal and abnormal group had significant difference(0.26 ± 0.054 VS 0.16 ± 0.066; 0.25 ± 0.040 VS 0.15 ± 0.054, P <0.01). The score in the color weak and color blindness group had significant difference(0.23 ± 0.058 VS 0.14 ± 0.044; 0.22 ± 0.054 VS 0.13 ± 0.025, P <0.01), while the color weak and normal group had no difference(0.23 ± 0.058 VS 0.26 ± 0.054; 0.22 ± 0.054 VS 0.25 ± 0.040, P> 0.05). According to the normal range of 95% in pilot environment color vision testing system and Air traffic controller color vision testing system, the eligibility standard for pilot with color vision was that the score of the applicant reached between 0.1319 and 0.3843 and the eligibility standard for air traffic controller was that the score achieved between 0.1521 and 0.3497.Conclusions: The color vision testing system of aviation environment showed different results between color weak and color blindness. The standard of aviation staff could provide evidence for the color vision capability of candidate with color weak to finish task of system.In summary, this study successfully designed a set of aviation staff color vision testing system. The system included FM100 color vision testing system and aviation environment color vision testing system. FM100 color vision testing system could provide qualitative and quantitative results about the ability of color vision and the cut off score of the testing system had a high sensitivity and specificity. So FM100 color vision testing system improved the effectiveness and accuracy of color vision examination. Aviation environment color vision testing system could make a decision about the capability of color vision to execute aviation task. The quantitative results provided by FM100 color vision testing system could lay foundation and evidence for aviation environment color vision testing system. The coalition of two parts might improve the rationality of color vision detection, which was conducive to supplement and improve the color vision inspection technique of civil aviation personnel. Finally to provide the basis for a more complete examination method for the color vision of civil aviation in the future. |
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