ఆప్టోమెట్రీ: ఓపెన్ యాక్సెస్

నైరూప్య

Visual Performance and Illuminance: A Case Study amongst First Year Students

Abdul-Sadik Ahmed

Purpose: This research investigated the effect of illumination on visual performance and visual fatigue in using liquid crystal display (LCD) of personal computers and paper print.

Methodology: The research was a descriptive cross sectional study. Two rooms were selected randomly for the study: study room and hall room. 25 first year students were randomly selected for the study. Three illuminance levels were used: 30 lux (hall room illumination), 130 lux (study room illumination) and 1440 lux (‘sunlight illumination’ – still in study room).

Results: All the rooms used for the study had electrical illumination available. In the each room electrical illumination was by compact fluorescein lighting (CFL). There were no shadows cast which interfered with reading at the various illumination levels. Legibility testing showed that all participants were able to identify the same optotype under each illumination level. Visual Accuracy testing showed that illumination affected visual accuracy significantly with paper display than with computer display. Students were more accurate on the paper display than on the computer display across all illumination levels. Search time results showed that participants were generally faster with computer display than with paper display. However search time significantly decreased with paper display across all illumination levels. Visual discomfort results showed that illumination had an effect on discomfort with visual discomfort generally increasing with LCD screen than with paper display across the illumination levels.

Conclusion: Visual performance increased with increasing illumination and was better with paper display than with LCD screen of a computer.

 Recommendations: Illuminance levels should be increased by proper lighting procedures and alternatives to laptop computer displays which provide optimum visual performance like paper print such as E-paper, should be sought out.