# The Effect of 3D TVs on Eye Movement and Motor Performance
## 4 Discussion  
### The Effect of Environment (3D TV)  
The result of a repeated measures ANOVA revealed that environment had significant effects on eye movement time, index of eye performance, time to first fixation, saccade duration, revisited fixation duration, eye gaze accuracy, hand movement time, and index of hand performance. However, there were no significant main effects of environment on number of fixations and error rate. Participants were found to have longer eye movement time, lower index of eye performance, longer time to first fixation, longer saccade duration, longer revisited fixation duration, lower eye gaze accuracy, longer hand movement time, and lower index of hand performance when the target was presented in a 3D environment. Theoretically, eye movement should be faster than hand movement. Participants assured the position of the target until they decided to move their hand to click the \begin{table}
\begin{tabular}{c l l l l} \hline \hline
**No** & \multicolumn{1}{c}{**Dependent Variable**} & \multicolumn{1}{c}{**Environment**} & \multicolumn{1}{c}{**Depth**} & \multicolumn{1}{c}{**Index of Difficulty**} \\ \hline
1 & Eye Movement Time (second) & \(p\) = 0.036, F\({}_{1,11}\) = 5.732 & \(p\) = 0.385, F\({}_{2,22}\) = 1.372 & \(p\) = 0.274, F\({}_{5,55}\) = 12.760 \\
2 & Index of Eye Performance (bits/second) & \(p\) = 0.043, F\({}_{1,11}\) = 5.249 & \(p\) = 0.288, F\({}_{2,22}\) = 1.317 & \(p\) = 0.000, F\({}_{5,55}\) = 11.353 \\
3 & Number of Fixations & \(p\) = 0.216, F\({}_{1,11}\) = 1.726 & \(p\) = 0.938, F\({}_{2,22}\) = 0.064 & \(p\) = 0.000, F\({}_{5,55}\) = 15.022 \\
4 & Time to first Fixation (second) & \(p\) = 0.048, F\({}_{1,11}\) = 4.965 & \(p\) = 0.677, F\({}_{2,22}\) = 0.398 & \(p\) = 0.841, F\({}_{5,55}\) = 0.408 \\
5 & Saccadic Duration (second) & \(p\) = 0.014, F\({}_{1,11}\) = 8.481 & \(p\) = 0.300, F\({}_{2,22}\) = 1.271 & \(p\) = 0.000, F\({}_{5,55}\) = 18.512 \\
6 & Revisited Fixation Duration (second) & \(p\) = 0.031, F\({}_{1,11}\) = 6.122 & \(p\) = 0.604, F\({}_{2,22}\) = 0.556 & \(p\) = 0.000, F\({}_{5,55}\) = 47.224 \\
7 & Eye Fixation Accuracy & \(p\) = 0.014, F\({}_{1,11}\) = 8.559 & \(p\) = 0.677, F\({}_{2,22}\) = 13.799 & \(p\) = 0.000, F\({}_{5,55}\) = 13.799 \\
8 & Hand Movement Time (second) & \(p\) = 0.002, F\({}_{1,11}\) = 15.879 & \(p\) = 0.385, F\({}_{2,22}\) = 0.996 & \(p\) = 0.000, F\({}_{5,55}\) = 144.887 \\
9 & Index of Hand Performance (bits/second) & \(p\) = 0.001, F\({}_{1,11}\) = 22.317 & \(p\) = 0.238, F\({}_{2,22}\) = 1.532 & \(p\) = 0.000, F\({}_{5,55}\) = 28.899 \\
10 & Error Rate (\%) & \(p\) = 0.777, F\({}_{1,11}\) = 0.084 & \(p\) = 0.747, F\({}_{2,22}\) = 0.296 & \(p\) = 0.000, F\({}_{5,55}\) = 9.920 \\ \hline \hline \end{tabular}
\end{table} 
Table 13: Summary of the findings. target. Eyes will guide the hand to click target when the eyes fixate on the position of the target [40]. In this study, participants required a longer time to click the virtual target in the 3D environment compared with the target in the 2D environment. It appears that in the 2D environment, participants perceived the target clearly without any difficulty and confusion, and therefore, the participants could determine the target in screen displays faster and more effectively than the virtual target in the 3D environment. The index of eye performance was higher than the index of hand performance because the extraocular muscles that shift the eye are the fastest muscle in the human body [41]. Therefore, the speed gain of the eye made a difference over the hand for the same distances and resulted a higher index of eye performance. Our study is consistent with [42], which reported that eye performance was much higher than hand click performance. The index of hand and eye performances in the 3D environment was lower than in the 2D environment. This condition happened because the movement time in the 3D environment was longer than movement time in the 2D environment.