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

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


*p*> 0.05 ; N = 8

176 Virtual Reality and Environments

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

Table 3 presents the result of experiment on the effect of field of view (FOV). There are two types of FOV namely 1200 and 850 FOV. Statistical binomial test at 5% significant level shows the same result of visual symptoms effect experienced by users but at different proportion especially the eyestrain and dry and irritated eyes symptoms. For 120 degree of FOV, 63% of the users experienced dry and irritated eyes while only 50% of the users experienced it for 85 degree of FOV. 75% of the users experienced eyestrain symptom at 850

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

Eyestrain Blurred Vision Dry and Irritated Eyes

Eyestrain Blurred Vision Dry and Irritated Eyes

Table 3. Result of Experiment and Binomial Test of Visual Symptoms of Field of View

Table 4 shows the result of experiments on the effect of flow rate (FR) of virtual object on visual symptoms of the subjects. There are two types of flow rate studied, which are five

Table 4. Result of Experiment and Binomial Test of Visual Symptoms of Flow Rate (FR) of

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

Eyestrain Dry and Irritated Eyes

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

**(1-tailed) Decision** 

Effect Effect

Effect Effect Effect

0.633 0.114

0.633 0.114 0.114 Effect Effect Effect

Effect Effect Effect

0.114 0.114 0.321

0.633 0.114 0.114

brightness, dry and irritated eyes were experienced by 67% of the users.

of FOV and 50% of the users experienced it at 1200 of FOV.

50 50 63

75 50 50

75 50

75 50 50

**No. Degree of FOV Observation** 

**3.4 Effect of flow rate of virtual object** 

**No. Flow Rate (FR) Observation** 

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

**3.3 Effect of field of view** 

**1.** FOV 1200

**2.** FOV 850

**1.** Flow Rate 5 (FR5)

**2.** Flow Rate10 (FR10)

*p*> 0.05 ; N = 8

Virtual Object

*p*> 0.05 ; N = 8

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


*p*> 0.05 ; N = 8

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

Ergonomics Design Criteria of a Virtual Environment 179

(b) exhibit the levels of eyestrain and blurred vision symptoms experienced by users when interacting with the VE. Only the red colour significantly resulted in blurred vision. This might be caused by the red colour causing discomfort to the eyes when a virtual object is in motion. The colour is also quite glaring in such a way that it would be difficult for the eyes

(a)

(b)

Fig. 2. (a) Level of eyestrain symptoms (b) Level of blurred vision symptoms
