Effects of flicker on reading comfort (part 2) Essay

Effects of flicker on reading comfort (part 2) - Essay Example Two types of questionnaire, an initial questionnaire to identify the previous experience of discomfort and a symptom questionnaire were used. Results: The results indicated insignificant difference between discomforts caused by sustained reading and using computer. The condition of 50 Hz induced the greatest impact on reading comfort compared to DC. The most affected symptoms of discomfort were vision discomfort followed by eyestrain, blurred vision and headache. The mean difference of 75 Hz, 100 Hz and 140 Hz compared to DC lighting situation was not significant. Conclusion: The study shows that reading under 100 Hz LEDs light has no different effects on comfort than reading under LEDs light powered on DC. In addition, the study shows insignificant difference between discomfort induced by reading and by computer use in terms of incidence and nature. Further studies are required with larger and balanced sample size, different direction of illumination and longer period of reading tim e to address the possible limitations of this experiment. Methods Participants Students of the University of New South Wales (UNSW) were invited by posters and emails to participate in the experiment. Participants who completed the experiment received a nominal reward. The inclusion criteria were good binocular vision, lack of ocular and systemic abnormalities that possibly influence reading ability, and age had to be between 19 to 30 years old since light sensitivity often higher at this age group. The exclusion criteria were any known case of migraine or photosensitive epilepsy. A total number of 18 students were recruited (2 male and 16 female), all signed an informed consent form prior commencing the study. Ethics and the study protocol were reviewed and approved by the UNSW Human Research Ethics Advisory (UNSW HREA) Panel. Design and Procedure In a double masked randomized crossover study, discomfort symptoms were self-reported by using two types of questionnaires; an initial q uestionnaire and symptoms questionnaire. The participants had to attend five reading sessions under LED light, but with different rate of flicker in each session. They were randomly assigned to the sessions by Latin squares, and the reading sessions had to be separated by at least one day. At the beginning of the first session, the initial questionnaire had to be completed, whereas symptom questionnaire had to be filled immediately at the beginning and at the end of every session to evaluate reading discomfort. During the reading sessions, the ambient light was turned off, and the room was completely dark, so the only light source was that installed in lighting booth. The booth was positioned on a table, and a â€Å"twilight† novel was placed inside the booth directly under the light. Each subject had to read a part from the book on every session for 30 minutes with the habitual glasses. Comfortable sitting was enhanced by providing an adjustable chair placed in front of the booth to read with habitual reading posture. Questionnaires Two types of questionnaires were used in the study: the initial questionnaire and the symptom questionnaire. The initial questionnaire was designed to examine the previous experience of discomfort related to reading and computer use and to detect unknown cases of photosensitive epilepsy or migraine. The first part of the questionnaire was