Table 4

Multiple logistic regression showing the associated risk factors of CVS

Factor	Univariate analysis			Multiple analysis
Factor	Crude OR	95% CI	P value	Adjusted OR	95% CI	P value
Age ≤15	2.34	1.63 to 3.36	<0.001	2.17	1.36 to 3.45	0.01
Female	1.73	1.34 to 2.23	<0.001	1.26	0.90 to 1.75	0.178
Overall digital usage >6 hours	7.41	5.52 to 9.96	<0.001	1.91	1.13 to 3.23	0.016
Online learning >5 hours	7.99	6.07 to 10.53	<0.001	4.99	3.08 to 8.12	<0.001
Refractive error	1.35	1 to 02 to 1.79	0.035	2.89	1.83 to 4.54	<0.001
Refractive error
Myopia	3.21	2.31 to 4.44	<0.001	2.11	1.24 to 3.32	<0.001
Emmetropia	3.19	2.21 to 4.60	<0.001	2.09	2.14 to 3.47	<0.001
Hyperopia	Ref			Ref
Fan	2.55	1.86 to 3.48	<0.001	1.2	0.81 to 1.81	0.362
Non-protective device used	1.82	1.19 to 2.79	0.006	1.07	0.66 to 1.73	0.793
Protective device
Both	4.62	2.90 to 7.38	<0.001	0.66	0.39 to 1.11	0.118
Blue-coated glasses	3.36	2.52 to 4.49	<0.001	1.19	0.71 to 1.99	0.508
Blue-coated film	Ref			Ref
Rest of over 45 min	2.59	2.01 to 3.34	<0.001	1.02	0.7 to 1.48	0.935
Other digital devices used >2 hours	2.22	1.73 to 2.85	<0.001	0.89	0.61 to 1.28	0.52
Distance from device <40 cm	2.42	1.78 to 3.30	<0.001	1.07	0.71 to 1.63	0.743
Back pain	2.84	2.12 to 3.80	<0.001	2.06	1.32 to 3.22	0.001
Neck pain	2.59	1.94 to 3.46	<0.001	2.64	1.89 to 3.70	<0.001
Multiple digital devices used	3.6	2.76 to 4.70	<0.001	2.15	1.04 to 4.43	0.038
Non-use of artificial tears	0.96	0.70 to 1.30	0.77	1.34	0.91 to 1.98	0.133
Close eyes during online learning	1.69	1.32 to 2.17	<0.001	1.12	0.80 to 1.55	0.508
Sleep during online learning	2.12	1.64 to 2.74	<0.001	1.29	0.93 to 1.79	0.135
Laptop computer preference	2.36	1.75 to 3.19	<0.001	0.83	0.48 to 1.42	0.494
Tablet preference	2.27	1.77 to 2.92	<0.001	0.86	0.51 to 1.45	0.568
Television screen preference	1.49	0.49 to 4.55	0.49	1.067	0.30 to 3.75	0.92
Computer desktop preference	1.37	1.07 to 1.77	0.016	1	0.61 to 1.66	0.987
Mobile phone preference	1.34	1.03 to 1.69	0.031	0.81	0.50 to 1.31	0.395

CVS, computer vision syndrome.