Visual Sequelae of Computer Vision Syndrome: A Cross-Sectional Case-Control Study

Table 9

Differences between the control and CVS groups.

Parameters	Control group; (n = 176 eyes of 176 students); (Mean ± SD); Median (range)	CVS group; (n = 557 eyes of 557 students); (Mean ± SD); Median (range)	Mean difference; (Control-CVS); 95% confidence of Interval	value
Visual outcomes (logMAR):
UDVA	0.13 ± 0.12	0.31 ± 0.25	−0.18	<0.0001
	0.1 (−0.1 : 0.5)	0.3 (−0.1 : 1.1)	(−0.22 : −0.09)
CDVA	−0.016 ± 0.04	−0.002 ± 0.01	−0.014	<0.0001
	0 (−0.1 : 0)	0 (−0.1 : 0)	(−0.018 : −0.008)
Subjective refraction (D):
Sphere	−0.51 ± 1.13	−0.90 ± 1.12	0.39	<0.0001
	−0.13 (−4:2.5)	−0.75 (−5:4)	(−0.02 : 0.53)
Cylinder	−0.25 ± 0.61	−0.51 ± 0.74	0.26	<0.0001
	0 (−4:1)	−0.25 (−4:2.75)	(0.17 : 0.41)
SE	−0.63 ± 1.19	−1.16 ± 1.42	0.53	<0.0001
	−0.5 (−4:2.5)	−0.88 (−6.25 : 4.25)	(0.24 : 0.68)
DED tests:
Tear film break-up time:				<0.0001
TBUT in seconds	12.38 ± 1.78	8.93 ± 2.16	3.45
	12 (7 : 17)	9 (2 : 15)	(4.26 : 3.12)
Abnormal TBUT test (<10 seconds)	5 eyes (2.8%)	336 eyes (60.3%)		<0.0001
Schirmer test: Schirmer test in mm	19.57 ± 4.07	10.68 ± 4.37	8.89	<0.0001
	20 (8 : 29)	9 (5 : 26)	(10.94 : 8.46)
Abnormal Schirmer test (<10 mm)	5 eyes (2.8%)	301 eyes (54%)		<0.0001
Slit-lamp examination:
Conjunctival hyperemia (eye redness)	11 eyes (6.3%)	181 eyes (32.5%)		<0.0001
Watery/mucous discharge	0 eyes (0%)	3 eyes (0.5%)		<0.0001
Normal fundus examination:	100%	100%
Students/eyes documented with
Diagnosed CVS cases	0 cases (0%)	557 cases (100%)		<0.0001
Reduced UDVA (worse than 0.00 logMAR)	101 eyes (57.4%)	409 eyes (73.4%)		0.001
Reduced CDVA (worse than 0.00 logMAR)	0 eyes (0%)	0 eyes (0%)		1.00
Diagnosed DED cases	5 eyes (2.8%)	336 eyes (60.3%)		<0.0001

UDVA: uncorrected distance visual acuity; CDVA: corrected distance visual acuity; TBUT: tear film break-up time test; CVS: computer vision syndrome; DED: dry eye disease; SE: spherical equivalent; logMAR logarithm of the minimum angle of resolution.