Table 2 Conditions for computer use and association with CVS

Eyeglass wearer

 No

236 (72.6)

181 (76.7)

1.0 (0.6; 1.8)

n.s

 Yes

89 (27.4)

68 (76.4)

1

1

Knowledge

 About ergonomics

  No

276 (84.9)

214 (77.5)

1.4 (0.7; 2.7)

n.s

  Yes

49 (15.1)

35 (71.4)

1

1

  No

289 (88.9)

227 (78.5)

2.3 (1.1; 4.8)

4.5 (1.2; 16.2)

  Yes

36 (11.1)

22 (61.1)

1

1

 About 20–20-20 rule

  No

270 (83.1)

220 (81.5)

3.9 (2.1; 7.3)

5.1 (2.1; 12.5)

  Yes

55 (16.9)

29 (52.7)

1

1

 Abaout CVS

  No

246 (75.7)

190 (77.2)

1.1 (0.6; 2.1)

n.s

  Yes

79 (24.3)

59 (74.7)

1

1

 Computer use purposes

  Work

40 (12.3)

29 (72.5)

1

1

  Study

90 (27.7)

82 (91.1)

3.8 (1.4; 10.6)

4.8 (1.1; 20.8)

  Study and leisure

168 (51.7)

119 (70.8)

0.9 (0.4; 1.9)

n.s

  Study, work and leisure

27 (8.3)

19 (70.4)

0.9 (0.3; 2.6)

n.s

 Hours of computer use per day

  </= 6 h

173 (53.2)

115 (66.5)

1

1

  >6 h

152 (46.8)

134 (88.2)

3.8 (2.1; 6.7)

7.7 (3.1; 19.1)

  Without breaks

156 (48.0)

118 (75.6)

1.3 (0.6; 2.7)

n.s

  activities that require near vision

122 (37.5)

98 (80.3)

1.7 (0.8; 3.7)

n.s

  activities that do not require near vision

47 (14.5)

33 (70.2)

1

1

 Computer use distance

  ≥40 cm

60 (18.5)

45 (75.0)

1

1

  <40 cm

265 (81.5)

204 (77.0)

1.1 (0.5; 2.1)

n.s

 Monitor with anti-glare

  No

189 (58.2)

161 (85.2)

3.1 (1.8; 5.3)

2.5 (1.2; 5.6)

  Yes

136 (41.8)

88 (64.7)

1

1

 Have you adjusted the monitor brightness?

  No

134 (41.2)

103 (76.9)

1.0 (0.6; 1.7)

n.s

  Yes

191 (58.8)

146 (76.4)

1

1

 Have used other VDTs

  None

55 (16.9)

23 (41.8)

1

1

  Smartphone

190 (58.5)

156 (82.1)

6.3 (3.3; 12.2)

13.8 (5.4; 35.6)

  Smartphone and tablet

80 (24.6)

70 (87.5)

9.7 (4.1; 22.8)

29.5 (8.7; 100.1)

Workplace

 Lighting

  Good

139 (42.8)

102 (73.4)

1

1

  Poor

100 (30.8)

80 (80.0)

1.5 (0.8; 2.7)

n.s

  Dark

86 (26.5)

67 (77.9)

1.3 (0.7; 2.4)

n.s

 Light source

  Natural light

65 (20.0)

49 (75.4)

1

1

  Incandescent

137 (42.2)

108 (78.8)

1.2 (0.6; 2.4)

n.s

  Fluorescent

123 (37.8)

92 (74.8)

1.0 (0.5; 1.9)

n.s

 Air conditioning in the workplace

  Without

236 (72.6)

183 (77.5)

1

1

  With

89 (27.4)

66 (74.2)

0.8 (0.4; 1.5)

n.s

Posture

  Sitting (bed/mat/floor)

70 (21.5)

57 (81.4)

1.8 (0.7; 5.0)

n.s

  Sitting (inappropriate chair)

188 (57.8)

145 (77.1)

1.4 (0.6; 3.4)

4.8 (1.3; 18.4)

  Lying down

37 (11.4)

26 (70.3)

1.0 (0.3; 2.9)

n.s

  sitting (appropriate ergonomic chair)

30 (9.2)

21 (70.0)

1

1

  No

277 (85.2)

214 (77.3)

1.2 (0.6; 2.5)

n.s

  Yes

48 (14.8)

35 (72.9)

1

1

  No

229 (70.5)

181 (79.0)

1.5 (0.9; 2.7)

n.s

  Yes

96 (29.5)

68 (70.8)

1

1

  No

129 (39.7)

96 (74.4)

1

1

  Yes

196 (60.3)

153 (78.1)

1.2 (0.7; 2.1)

n.s