A Meta-Analysis for Association of Maternal Smoking with Childhood Refractive Error and Amblyopia

Table 1

Characteristics of the included studies.

Author	Publication year	Study location	Studying time	Age	Style	N1	N2	Cycloplegia	Adjustments	OR, 95% CI	Definitions
Iyer et al. [7]	2012	Singapore	NA	40.5 (6–72) m	Refractive error: myopia	137	2502	Yes	Adjusted for age, gender, total family income, father’s and mother’s education, height, parental myopia, reading words or picture books, and total time spent outdoors	0.39 (0.20–0.76)	The definition of myopia was SER of at least −0.5 D
Borchert et al. [10]	2011	USA	NA	6 to 72 m	Refractive error: myopia	378	9515	Yes	No	1.08 (0.74–1.56)	Myopia was defined as SER error ≤−1.00 D
			NA	6 to 72 m	Refractive error: hyperopia	1788	6781	Yes	No	1.42 (1.20–1.68)	Hyperopia was defined as SER error ≥+2.00 D
McKean-Cowdin et al. [15]	2011	USA	NA	6 to 72 m	Refractive error: astigmatism	859	7720	Yes	Adjusted for age, race, and spherical equivalent of the right eye	0.98 (0.65–1.47)	Astigmatism was defined using a threshold level of cylindrical refractive error in the right or left eye of ≥1.50 D expressed in positive correcting cylinder form
Stone et al. [8]	2006	USA	NA	8.7 ± 4.4 y	Refractive error: myopia	63	279	Yes	No	0.34 (0.08–1.50)	Myopia was defined as a spherical equivalent refraction of ≤−0.5 D for the mean of both eyes
Pai et al. [16]	2012	Australia	2007–2009	6–72 m	Amblyopia	27	1395	Yes	Adjustments for age, gender, ethnicity, and SER	1.41 (0.26–7.69)	Amblyopia was defined using the MEPEDS criteria and divided into unilateral and bilateral subtypes
Chia et al. [17]	2013	Singapore	2006–2009	30–72 m	Amblyopia	20	1662	Yes	No	1.31 (0.08–22.08)	Unilateral amblyopia was defined as a 2-line difference between eyes with VA < 20/30 in the worse eye; bilateral amblyopia was defined as VA in both eyes < 20/40
Robaei et al. [18]	2006	Australia	2003-2004	6 years old	Amblyopia	32	1733	Yes	No	2.20 (1.00–5.00)	Amblyopia was initially defined as corrected VA less than 0.3 logMAR units in the affected eye not attributable to any underlying structural abnormality of the eye or visual pathway plus a difference of at least 2 logMAR lines between the 2 eyes
Williams et al. [3]	2008	UK	1998–2000	NA	Amblyopia	239	6696	No	No	1.40 (1.04–1.86)	Amblyopia was defined as those with a history of patching treatment and/or with an interocular difference in best acuity for each eye of 0.2 logMAR units where the worst-seeing eye had a best acuity of worse than 0.3 logMAR, and the eye looked normal on dilated funduscopy
Ip et al. [19]	2008	Australia	NA	6 years old	Refractive error: Hyperopia1	35	153	Yes	No	1.50 (1.04–2.30)	Hyperopia was defined as an SER of +0.50 D or greater and was stratified as mild or moderate
			NA	12 years old	Refractive error: Hyperopia2	22	282	Yes	No	1.40 (0.90–2.30)	Myopia was defined as an SER of −0.50 D or less

m: months; y: years; N1: with refractive error or amblyopia; N2: without refractive error and amblyopia; EVA: Electronic Visual Acuity; SPEDS: the Sydney Paediatric Eye Disease Study; SER: spherical equivalent refraction; MEPEDS: Multiethnic Pediatric Eye Disease Study; D: diopters; VA: visual acuity.