New Keratoconus Risk Factors: A Cross-Sectional Case—Control Study

Table 2

Risk factors of keratoconus and univariate analysis.

	Cases, N = 195	Controls, N = 195	value^1
Rubbing eyes			<0.001
Active	108 (55)	66 (34)
Never	31 (16)	129 (66)
Past: stopped	56 (29)	0 (0)
Eye rubbing history (past or active)	164 (84)	66 (34)	<0.001
Family history	39 (20)	2 (1.0)	<0.001
Dry eyes	81 (42)	19 (9.7)	<0.001
History of eyes irritative acnea treatment (retinoid)	6 (3.1)	7 (3.6)	0.78
Screen time per day			0.10
<4 hr	82 (42)	98 (50)
≥4 hr	113 (58)	97 (50)
Sleeping data
Snoring or OSA	41 (21)	27 (14)	0.065
Missing	0	1
Regular sleep	112 (61)	111 (57)	0.44
Missing	11	0
On the back	50 (26)	47 (24)	0.73
On the side	131 (67)	122 (63)	0.34
Head in the pillow	44 (23)	51 (26)	0.41
Hand or forearm on the eye	20 (10)	7 (3.6)	0.010
Exposure data
Dry condition or air conditioning	46 (24)	61 (31)	0.083
Missing	0	1
Smoking (tobacco or cannabis)	59 (30)	38 (20)	0.015
Missing	0	1
Animals	61 (31)	68 (35)	0.43
Missing	0	1
Allergy data
Allergy (any kind)	124 (64)	78 (40)	<0.001
Missing	2	0
Asthma	39 (20)	15 (7.7)	<0.001
Skin allergies	29 (15)	23 (12)	0.37
Allergic rhinitis or hay fever	53 (27)	40 (21)	0.12
Allergic conjunctivitis	78 (40)	26 (13)	<0.001
Angioedema	7 (3.6)	1 (0.5)	0.068
Drug allergies	12 (6.2)	19 (9.7)	0.19
Food allergies	15 (7.7)	10 (5.1)	0.30

OSA = obstructive sleep apnea. Data are n (%); the ¹chi-square test; and the Fisher’s exact test.