Continuous Motion Tracking For Accurate And Efficient Color Vision Screening

Assessment of color vision is important for both fundamental visual research and clinical diagnosis.And a good color vision detection method can not only screen and classify the anomalmous trichromat;but also get an individual’s sensitivity to a specific color.However,the existing tools for color vision assessment are limited by multiple factors.Here we reported a new efficient method of color vision assessment,which is based on a continuous motion tracking task and a Kalman filter model.There are two main parts in the study.The first part aimed to explore the effectiveness of continuous motion tracking task in screening individuals with abnormal color vision.There are two tasks in the first part: one is the traditional psychophysical method,the other one is the continuous motion tracking task.The target visual stimulus of the two tasks include two colors,red―green and blue―yellow,taken from the L-M and S-(L+M)axes of the DKL color space,respectively.In the continuous motion tracking task,the contrasts of the two colors included 7levels(red―green : 2 %,4 %,8 %,15 %,28 %,53 %,100 %;blue―yellow : 6 %,10 %,16 %,25 %,40 %,63 %,100 %).By the traditional method,we found that there were significant differences in red-green threshold between the individuals with abnormal color vision and the individuals with normal color vision.By the continuous motion tracking task,we found that there were significant differences in tracking performance between the individuals with abnormal color vision and the individuals with normal color vision at red―green 8%-53% contrast level,and even at 15%-28% contrast levels,the continuous motion tracking task could perfectly distinguish individuals with abnormal color vision from individuals with normal color vision(AUC=1).It is shown that the continuous motion tracking task can effectively screen the anomalmous trichromat.The second part aimed to normalize the screening of the anomalmous trichromat by the continuous motion tracking task.The red―green,blue―yellow colors were also selected,the contrast level was based on the results of the first part.Four level contrast were selected(red―green : 8 %,15 %,28 %,53 %;blue―yellow : 16 %,25 %,40 %,63 %).The duration of this continuous motion tracking was five minutes.The results showed that the tracking performance of the normal individuals were normal distribution under the specific conditions(red ― green: 15%-53%,blue ―yellow: 25%-63%).In addition,the 20-second continuous motion tracking could screen the anomalmous trichromat perfectly under the condition of red―green 15%contrast(AUC = 1).Standardized testing rules are: color: DKL color space L-M axis;contrast: 7.6 times the normal’s red―green threshold;motion: two white Gaussian noise sequences(SD = 0.0255°)are randomly shifted for 20 seconds on the x-axis and y-axis,respectively;judgement: when the tracking performance of the subject is lower than-2.7 standard deviation,the subject is anomalmous trichromat.In a short,the continuous motion tracking test can not only classify individuals with abnormal or normal color vision,but also to assess the color vision of both individuals with abnormal and normal color vision.Importantly,this new method has almost perfect sensitivity and specificity in screening individuals with abnormal color vision.It can better estimate human sensitivity to color contrast like traditional psychophysical methods.Compared with the traditional psychophysical methods,it takes only 20 seconds to evaluate an individual’s color vision function by the new method,which is more efficient than the traditional method.It proved that the continuous motion tracking method is a promising tool both for quick screening of color vision deficiency and for fundamental research on color vision.