The effects of reflected glare and visual field lighting on computer vision syndrome

Abstract

Background

Computer vision syndrome is common and affects performance of visual tasks. Background illumination, light source, light compensation, position of the display, contrast and glare are environmental factors associated with computer vision syndrome. The aim of this study is to investigate the effects of reflected glare and visual field lighting on computer vision syndrome.

Methods

In a reflected glare experiment, participants performed a two‐hour visual task using a glossy, matte, or glare‐free surface display in two visual environments (normal, glare). In a visual field lighting experiment, participants performed the visual task in dim lighting, uneven supplementary lighting, or uniform supplementary lighting. Visual function parameters, including critical fusion frequency, heterophoria, amplitude of accommodation and accommodative facility were evaluated by the investigators and a visual fatigue questionnaire was completed before and after the visual task. Visual performance was also recorded. In addition, the variation of pupil size under different lighting conditions was analysed.

Results

Critical fusion frequency was the only visual function parameter which decreased significantly after the visual task. The questionnaire score was significantly higher in a glare environment and was lower when the task was performed using a glare‐free display. Visual performance was significantly worse in the glossy display group. The increment in the questionnaire score was smaller in the uniform supplementary lighting group. Visual performance was significantly worse in the dim lighting or uneven supplementary lighting group, but not in the uniform supplementary lighting group. Variation in pupil size was significantly greater in the dim lighting condition than in the supplementary lighting condition.

Conclusion

Critical fusion frequency is an effective indicator of computer vision syndrome. Glare‐free displays could alleviate visual fatigue and preserve visual performance. Uniform supplementary lighting could decrease variation in pupil size and prevent eye strain.

Key words:

• computer vision syndrome
• critical fusion frequency
• glare
• supplementary lighting

Supporting information

Additional supporting information may be found in the online version of this article at the publisher’s website:

Figure S1. The questions and rating scale in the visual fatigue questionnaire.

Figure S2. The questions and rating scale in the glare questionnaire.

Figure S3. The illustration demonstrates the calculation of specular reflectance.

Figure S4. The example of a visual comparison test.

Figure S5. Diagram showing the three visual field lighting conditions used in the study. A: Dim room lighting (60 lux). B: Uneven supplementary lighting provided by a lamp on the left side in a dimly lit room. C: Uniform supplementary lighting around the display device in a dimly lit room.

Figure S6. Diagram showing the four different illumination conditions and methods of visual field lighting. A: Dim room lighting (60 lux). B: Uneven supplementary lighting provided by a lamp on the left side in a dimly lit room. C: Uniform supplementary lighting around the display device in a dimly lit room. D: Bright room lighting (300 lux).

Figure S7. The illustration of the distance between points on the screen.