**4.6 Analysis of the resolution of display**

Many research have been conducted and have concluded that working with LCD screen is much more comfortable compared to working with CRT screens (Alstrom, et al, 1992; Saito, et al, 1993; Shieh,K.K., and Lin, C.C., 2000). This is contributed to the luminance contrast and limited viewing angle of LCD screens (Snyder, 1988). Additionally, the TFT-LCD screen seems to be the preferred technology by users for identifying letters on VDTs (Shieh, K.K. and Lin, C.C.,2000). In the current research, statistical binomial test (Table 6) have found that eyestrain and dry and irritated symptoms were experienced by users at three different resolution (high, medium and low resolution) whilst dry and irritated eyes incidence were experienced by users

Ergonomics Design Criteria of a Virtual Environment 187

(c) Fig. 6. (a) Level of eyestrain symptoms (b) Level of blurred vision symptoms (c) Level of dry

Figures 7 (a), (b) and (c) shows the level of eyes symptoms for different resolution. To avoid eyestrain symptoms, high and low resolutions are preferred for LCD screen because more than

(a)

and irritated eyes symptoms

with the CRT screens at medium and low level of resolution only. This indicates that the resolution of display needs to be considered as one of the attributes in designing a VE.

(b)

with the CRT screens at medium and low level of resolution only. This indicates that the

(a)

(b)

resolution of display needs to be considered as one of the attributes in designing a VE.

Fig. 6. (a) Level of eyestrain symptoms (b) Level of blurred vision symptoms (c) Level of dry and irritated eyes symptoms

Figures 7 (a), (b) and (c) shows the level of eyes symptoms for different resolution. To avoid eyestrain symptoms, high and low resolutions are preferred for LCD screen because more than

(a)

Ergonomics Design Criteria of a Virtual Environment 189

Figures 8 (a), (b) and (c) describes the level of incidence experienced by users for different contrast ratios. The result of statistical binomial test in Table 7 shows that eyestrain was

(a)

(b)

**4.7 Analysis of the contrast ratio between target and background** 

Fig. 7. (a) Level of eyestrain symptom on LCD (b) Level of eyestrain symptoms on CRT (c) Level of dry and irritated eyes symptoms on CRT

40 % of user did not experience any strain. But for CRT screen, all resolution level can be used because there were no incidence eyestrain symptoms or dry and irritated eyes symptoms.

(b)

(c) Fig. 7. (a) Level of eyestrain symptom on LCD (b) Level of eyestrain symptoms on CRT (c)

40 % of user did not experience any strain. But for CRT screen, all resolution level can be used because there were no incidence eyestrain symptoms or dry and irritated eyes symptoms.

Level of dry and irritated eyes symptoms on CRT

#### **4.7 Analysis of the contrast ratio between target and background**

Figures 8 (a), (b) and (c) describes the level of incidence experienced by users for different contrast ratios. The result of statistical binomial test in Table 7 shows that eyestrain was

(b)

Ergonomics Design Criteria of a Virtual Environment 191

4. Virtual lighting at 100% level of brightness significantly affects visual symptoms,

The authors wish to acknowledge all of our participants who made this investigation possible. Appreciation is also accorded to University of Malaya for funding this project as

Ahlstrom, G., Lowden, A., Malmkvist, H., Schenkman, B.,Stoehr, R., Weselka, R., 1992. Field

ANSI/HFES100.(2007).National Standars for Human Factors Engineering of Computer

Barrett, Judy.(2004), Side effects of Virtual Environments: A Review of the Literature, DSTO-

Colombo, G., And Cugini, U.(2005).Virtual human and prototypes to evaluate ergonomics

Courtney, A.J., (1986). Chinese population stereotypes: color associations. Human Factors 28

Dukic, T., Rönnäng, M., And Christmansson, M.(2007). Evaluation of ergonomics in a virtual manufacturing process.Journal of Engineering Design.18(2). 125 – 137. Grether, W.F. and Baker, C.A.(1972). Visual presentation of information. In: Tayyari, F. and

Hu, B., Ma, L., Zhang, W., Salvendy, G., Chablat, C., Bennis, F.(2011).Predicting real-world

Lin, C.C.(2003).Effects of contrast ratio and text color on visual performance with TFT-

Menozzi, M.,Napflin, U., Krueger, H.(1999). CRT versus LCD: A pilot study on visual

Nichols, S.,(1999). Physical ergonomics of virtual environment use.Applied Ergonomics. 30.

Pappas, M., Karabatsou, V., Mavrikios, D., Chryssolouris, G.(2005).Ergonomic evaluation of

Saito, S., Taptagaporn, S., Salvendy, G., (1993). Visual comfort in using different VDT screens. International Journal of Human Computer Interaction. 1 (4), 313-323 Shaikh, I., Jayaram, U., Jayaram, S., Palmer, C.(2004). Participatory ergonomics using VR

LCD.International Journal of Industrial Ergonomics. 31. 65–72

Smith, J.L., (1997). Occupational Ergonomics; Principles and applications. London.

ergonomic measurements by simulation in a virtual environment.International

performance and suitability oftwo display technologies for use in office work.

integrated with analysis tools. Proceedings of the 2004 Winter Simulation

Anshel, J., (2005). Visual Ergonomics Handbook. New York. Taylor & Francis Group

and safety.Journal of Engineering Design.16(2). 195 – 207.

Journal of Industrial Ergonomics. 41. 64 – 71.

virtual assembly tasks. *Digital Enterprise Technology.*

study of a new type ofcomputer screen technology. In: Shieh, K.K., and Lin, C.C., (2000). Effects of screen type, ambient illumination, and color combination on VDT visual performance and subjective preference. International Journal of Industrial

particularly light sensitivity symptoms of the users.

well as to the Islamic University of Indonesia Yogyakarta Indonesia.

**6. Acknowledgements** 

Ergonomics . 26. 527-536

Workstations.HFES. p. 76

TR-1419,pp. 1-47.

Chapman & Hall.

Display.20. 3 – 10

Conference. USA.

79 – 90.

(1), 97–99

**7. References** 

Fig. 8. (a) Level of eyestrain symptom (b) Level of blurred vision symptoms (c) Level of dry and irritated eyes symptoms

experienced by most users (75%) for all condition of contrast. While blurred vision was experienced by 63% of the users at -50.83% contrast ratios and dry and irritated eyes was experienced by 50% of the users at 0% (-0.56%) contrast ratios. This is due to the contrast condition affecting the ability of the eyes to distinguish the target from the background. Thus the contrast ratio should be considered as one of the attributes or variables in designing a virtual environment.
