**3.1 Effect of colour of virtual background to visual symptoms**

Table 1 shows the results of the experiment describing the effect of colour of the virtual background on visual symptoms of the subjects. There are five types of colour used in this experiment, which are Red, Fuchsia, Dark Sky Blue, Medium Slate Blue and White. The colours were identified on the basis of user's preferences. Statistical binomial test at 5% significant level shows that the overall background colour has an effect on the user i.e. eyestrain and blurred vision syndrome. The eyestrain syndrome was experienced by 75% of users when Red and White background colours were used while 63% was experienced by the users when Fuchsia, Dark Sky Blue and Medium Slate Blue background colours were used. The blurred vision syndrome was only experienced by users when Red background colour was used.


*p*> 0.05 ; N = 8

Table 1. Result of Experiment and Binomial Test of Visual Symptoms of Colour Virtual Background


*p*> 0.05 ; N = 8

Table 2. Result of Experiment and Binomial Test of Visual Symptoms of Virtual Lighting

Ergonomics Design Criteria of a Virtual Environment 177

second per piece (FR 5) and ten second per piece (FR 10); corresponding to virtual object in sight every five second and ten second respectively. Statistical binomial test at 5% significant level shows that both types of flow rates have an effect on the users, in which 75% of the users experienced symptoms of eyestrain and 50% of the users also experienced blurred

Table 5 shows the result of the experiment on the effect of speed of virtual object on the subjects. Two levels of speed were investigated, that is slow motion (0.050) and fast motion (0.100). The result of statistical binomial test at 5% significant level proves that both speeds have an effect to the users where both slow and fast motion caused the same visual

**Proportion (%) Symptoms Exact Sig.** 

Eyestrain Blurred Vision Dry and Irritated Eyes

Eyestrain Blurred Vision Dry and Irritated Eyes

**Proportion (%) Symptoms Exact Sig.** 

89 Eyestrain 0.300 Effect

Table 5. Result of Experiment and Binomial Test of Visual Symptoms of Speed of a Virtual

*LCD*  **1.** High Resolution 56 Eyestrain 0.166 Effect

**<sup>3</sup>**Low Resolution 56 Eyestrain 0.166 Effect

*CRT*  **4.** High Resolution <sup>67</sup>Eyestrain 0.399 Effect

Table 6. Result of Experiment and Binomial Test of Visual Symptoms of Resolution of

Eyestrain Dry and Irritated Eyes

Eyestrain Dry and Irritated Eyes **(1-tailed) Decision** 

**(1-tailed) Decision** 

Effect Effect Effect

Effect Effect Effect

Effect Effect

Effect Effect

0.534 0.169 0.466

0.633 0.114 0.114

0.399 0.166

0.399 0.166

symptoms i.e. eyestrain, blurred vision, and dry and irritated symptoms.

83 50 67

75 50 50

**Observation** 

67 56

56

vision and dry and irritated eyes symptoms.

**3.5 Effect of speed of virtual object motion** 

**No. Level of Speed Observation** 

**1.** Low Speed

**2.** High Speed

**No. Level of** 

**2.** Medium Resolution

**5.** Medium Resolution

*p*> 0.05 ; N = 8

Display Type

**6.** Low Resolution <sup>67</sup>

**Resolution** 

*p*> 0.05 ; N = 8

Object

### **3.2 Effect of virtual lighting to visual symptoms**

The results of experiments on the effect of virtual lighting on visual symptoms are presented in Table 2. The experiment was conducted for four level of brightness of virtual light from darkest (10% level) to the brightest (100% level). The result of statistical binomial test at 5% significant level exhibiting the different effects of visual symptoms experienced by users is shown in Table 2. Eyestrain symptom was experienced by 83% of the users for all level of brightness. Whereas 50% the users experienced symptoms of dry and irritated eyes at 10% level of brightness and light sensitivity at 100% level of brightness. At the highest level of brightness, dry and irritated eyes were experienced by 67% of the users.
