The relation between parental smoking and hypermetropia

in childrenYair Morad

Yuval Cohen and Lionel Kowal Assaf Herofeh Medical Center, Zrifin, Israel

Royal Victorian Eye and Ear Hospital, Melbourne, Australia

Parental smoking inhibits child myopia

Saw et al: less myopia in children of smoking mothers (-0.28 D v -1.38 D) BJO 2004

Stone et al: If one or both parents ever smoked, their children had a lower myopia prevalence (12.4% vs. 25.4%) IOVS 2006

Can parental smoking cause hypermetropia ?

Maternal smoking associated with moderate hyperopia in six year old but not in 12 year old (N=4321) Ip et al Opthalmology 2008

AimTo examine the relation between

exposure to parental smoking and the development of hypermetropia in children

Design The database of a Pediatric Ophthalmology

Clinic was screened.1207 children with CR > 0.00DOnly one child from each family was selected

All parents underwent a telephone interview

The questionnaire

Father of mother smoking now? In the past?

How many packets per day?Did mother smoke during

pregnancy?

Children of farsighted parents were not included

Results 1007 children included in the studyMean age: 6.2 ± 3.6y (6mo - 17y)Mean spherical equivalent: +3.0±2.3 D

(0.0 - +12.75 D)

Mothers11% smoking today6.6% smoked in the past

Fathers21% smoking today11% smoked in the past

Maternal smoking and child’s refraction

P=0.1

P=0.014

Maternal smoking during pregnancy

0

1

2

3

4

5

6

Non (n=817) 0.2 (n=51) 0.5 (n=50) 0.75 (n=29) 1 (n=27)

Maternal smoking during pregnancy (PPD)

Chi

ld's

ref

ract

ion

P<0.0001

Parental smoking – not significant

Risk to develop esotropia

RR=1.63

Mother: non-smoking

70/817 = 8.5%Age: 6.9 ± 3.39Refraction : +5.2

Mother: smoking

17/122 =14% Age: 8.6 ± 3.18Refraction: +5.4

Pilot study in MelbourneN = 142 participants21% mother smoke; 16% smoked during

pregnancy26% father smoke; 32% smoked during

pregnancy32% have either parent smoking now38% have parent smoking during

pregnancy

ResultsSignificant association between smoking

mother and child hypermetropia (Odd ratio 19.75, CI 95% 1.65-236.51, p 0.02)

Smoking mother increases the odds of moderate to severe hyperopia (>+3 D) by nearly 20 folds

Other studiesStone et al IOVS 2006

N=323If one or both parents ever smoked, their children had

more hyperopic mean refractions (1.83 0.24 vs.0.96 0.27 diopters; P 0.02)

El-Shazaly et al Ophthalmic & Physiological Optics 2012

N=300Passive smoking exposure might be associated

with hypermetropia

Smoking increases the risk for esotropia Tasmania, Australia (n=346) Pediatric eye disease and Baltimore pediatric

eye disease studies (n=9970 )National Institute of Neurological Disorders

and Stroke, Bethesda, Md (n=39,227 )

Possible biochemical mechanism for smoking –refraction interaction

Nicotine stimulate dopamine release

Retinal dopamine

Eye growth

Nicotinic antagonists injected to old chicksinhibition of ocular growthhyperopic shifting of refraction

Stone RA et al IOVS 2001

Conclusions

1. Maternal smoking increase the risk of hypermetropia in children

2. The effect of maternal smoking is dose dependent.

3. Cigarette smoking increase the risk of esotropia in children