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Kim, Cho, and Song: Influences of Computer Works on Blink Rate and Ocular Dryness in Adolescents
Original Article

J Korean Ophthalmol Soc 2007;48(11):1466-1472.

Published online: 28 August 2007

DOI: https://doi.org/10.3341/jkos.2007.48.11.1466

Influences of Computer Works on Blink Rate and Ocular Dryness in Adolescents

Jun Sung Kim, M.D.1, Kyung Jun Cho, M.D.1, Jong-Suk Song, M.D.2,

1Sangsan High School, Junju, Korea

2Department of Ophthalmology, Korea University College of Medicine, Seoul, Korea

Address reprint requests to Jong-Suk Song, M.D., Department of Ophthalmology, Guro Hospital, Korea University College of Medicine, #80 Guro-dong, Guro-gu, Seoul 152-050, Korea, Tel: 82-2-2626-1276, Fax: 82-2-857-8580, E-mail: crisim@korea.ac.kr

Received 26 April 2007       Accepted 23 October 2007

Copyright © 2007 Korean Ophthalmological Society

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose

To evaluate the change in blink rate in adolescents according to the type and duration of computer tasks and to analyze the risk of ocular dryness using an ocular protection index.

Methods

Fifteen male high school students played computer games and viewed Internet lectures for 20 minutes each. Blink rate was measured by USB camera, and ocular protection index (OPI, the ratio of BUT to inter-blink interval) was calculated for each subject during the two tasks. In addition, 7 of the 15 subjects played computer games again for 40 minutes on another day, and the change in blink rate according to the duration of computer games was observed.

Results

The average blink rate was 5.44±3.29 per minute (median 5, range 2-12.75) while playing computer games and 20.63±11.21 per minute (median 18.25, range 4.93-42.2) while viewing Internet lectures, and this difference was statistically significant (p=0.001). The percentage of subjects with OPI values less than 1 was 53% for computer games and 13% for Internet lectures (p=0.025). While playing computer games for 40 minutes, the mean of total blinks during ten-minute intervals decreased over time: 59.43 times (median 57) during the first 10 minutes, 33.86 times (median 41) during the last 10 minutes.

Conclusions

The blink rate in adolescents was significantly lower and the risk of ocular dryness was higher while playing computer games compared with that of viewing internet lectures. As playing time increased, the blink rate decreased and risk of ocular dryness increased.

Keywords: Blink rate, Computer game, Dry eye, Ocular protection index, Visual display terminal

References

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Figure 1.
The change in total blink times during each 10 minutes while playing computer games.
jkos-48-1466f1.tif
Table 1.
Blinking rate and inter-blink interval in computer game and internet lecture
Subjects Computer game
 Internet lecture
 Tear BUT
Blink rate (times/min) Inter-blink interval (sec) Blink rate (times/min) Inter-blink interval (sec) (sec)
1 10.75 5.58 13.8 4.35 12.23
2 2.45 24.49 5.2 11.54 9.55
3 2.4 25 22.9 2.62 4.86
4 2.05 29.27 13 4.62 7.88
5 6.7 8.96 29.2 2.05 13.27
6 7.75 7.74 34.45 1.74 7.04
7 12.75 4.71 23.25 2.58 9.83
8 3 20 23.15 2.59 7.53
9 6.45 9.3 18.25 3.29 5.22
10 7 8.57 42.2 1.42 12.98
11 3.15 19.05 4.93 12.1 6.66
12 3.3 18.18 12.27 4.89 8.29
13 5 12 13.93 4.31 30
14 2 30 15.75 3.81 30
15 6.95 8.63 37.3 1.61 9.07
Median 5 12 18.25 3.29 9.07
Range 2-12.75 4.71-29.27 4.93-42.2 1.42-11.54 4.86-30
Mean±SD 5.44±3.29 15.43±8.76 20.63±11.21 4.23±3.28 11.62±7.87

BUT = break-up time.

SD = standard deviation.

Table 2.
Comparison of blink rate, inter-blink interval, and percentage of those having OPI values less than 1 between computer game and internet lecture (mean±standard deviation)
  Computer game Internet lecture P value
Blink rate (times/minute) 5.44±3.29 20.63± 11.21 P=0.001*
Inter-blink interval (second) 15.43±8.76 4.23±3.28 P=0.001*
Percentage of those having OPI values less than 1 53% 13% P=0.025†

OPI = ocular protection index.

* Wilcoxon signed ranks test.

† Fisher's exact test.

Table 3.
Changes in the blinking rate and the percentage of OPI less than 1 during 40 minutes of computer games
Subjects Blinking rate
 OPI less than 1 (%)
First 10 min Second 10 min Third 10 min Fourth 10 min First 10 min Second 10 min Third 10 min Fourth 10 min
1 21 15 7 6 52.3 73.3 71.4 83.3
2 57 53 45 42 21 22.6 42.2 47.6
3 84 58 55 41 38.1 51.7 67.3 68.2
4 81 66 51 43 0 4.5 5.9 11.6
5 55 36 35 28 14.5 13.9 31.4 39.3
6 25 23 26 20 60 74 54 70
7 93 89 73 57 4.3 4.5 12.3 17.5
Median 57 53 45 41 21 22.6 42.2 47.6
Range 21-93 15-89 7-73 6-57 0-60 4.5-74 5.9-71.4 11.6-83.3
Mean±SD 59.43±28.53 48.57±25.77 41.71±21.41 33.86±17.02 27.2±23.4 34.9±30.9 40.6±25.6 48.2±27.3

OPI = ocular protection index.

SD = standard deviation.

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