Download hyperopia&smoking.ASS.2008

An Unexpected Association
between Childhood Hyperopia
and Parental Smoking
Dr Elaine YH Wong
Ms Leanne Finch
Dr Christine Chen
Dr Lionel Kowal
Background
• Effects of nicotinic antagonists on
ocular growth and experimental myopia
Stone RA, Sugimoto R, Gill AS, Liu J, Capehart C, Lindstrom JM
Invest Ophthalmol Vis Sci. 2001 Mar;42(3):557-65
– 1-week old chicks, injected with nicotinic
antagonists – Chlorisondamine &
mecamylamine
– Inhibition of ocular growth and shift of
refraction towards hyperopia
Background
• Childhood myopia and parental
smoking.
Saw SM, Chia KS, Lindstrom JM, Tan DT, Stone RA
Br J Ophthalmol. 2004 Jul;88(7):934-7.
– N=1334, 8-11 yo school children
– Maternal smoking ? associated with hyperopic
refraction in children (p=0.03; but only 1.7% of
mothers smoked)
– Paternal smoking is not associated with refractive
error or axial length
Background
• Associations between childhood
refraction and parental smoking.
Stone RA, Wilson LB, Ying GS, Liu C, Criss JS, Orlow J, Lindstrom
JM, Quinn GE
Invest Ophthalmol Vis Sci. 2006 Oct;47(10):4277-87.
– N=323 from tertiary paediatric clinic
– If one or both parents ever smoked, their children
had a lower myopia prevalence (12.4% vs. 25.4%;
P = 0.004) and more hyperopic mean refractions
(1.83±0.24 vs 0.96±0.27 diopters; P =0.02)
– Smoking by either parent during the mother’s
pregnancy had a similar effect
Background
Prevalence of hyperopia and
associations with eye findings in 6- and
12-year-olds.
Ip JM, Robaei D, Kifley A, Wang JJ, Rose KA, Mitchell P
Ophthalmology. 2008 Apr;115(4):678-685.
– N = 1765 (6 yo); N = 2353 (12yo)
– Maternal smoking associated with moderate
hyperopia in 6 yo but not 12 yo
– Smoking during pregnancy – borderline significant
with moderate hyperopia (p=0.055)
• Not significant when controlled for ethnicity
– Moderate hyperopia is significantly associated with
amblyopia, strabismus, poor stereoacuity and
abnormal convergence
The Pilot Study
• Aim
– To explore the relationship between hyperopia and
parental smoking in a population who present to a
subspecialty strabismus practice
• Methods
– Patients between the age of 0 -12 undergoing a
cycloplegic retinoscopy were recruited
– A short questionnaire was administered to the
accompanying parent[s]
• Information regarding parental smoking status, gestational
smoking status, parental refractive error and ethnicity were
collected
Patient Label
Associations between Childhood Refraction and Parental Smoking
Patient’s cycloplegic refraction:
Right Eye: _______________________ Left Eye: ___________________________
QUESTION 1. Parents’ race (please tick):
Father: Caucasian______Asian: ______ Mother: Caucasian: ______ Asian: ______
Other (please write): _____________ Other (please write): ______________
QUESTION 2. Are either of the patient’s parents long or short-sighted (tick which)?
Father: hyperopic _____
Mother: hyperopic _____
myopic _______
myopic _______
unknown: _____
unknown: _____
QUESTION 3. Do either of the patient’s parents smoke?
Father: yes / no / former smoker
Mother: yes / no / former smoker
If both parents answered no to question 3, the questionnaire is now complete.
QUESTION 4. If yes, how long have you smoked for?
Father 1: _______ years
Mother: _______ years
QUESTION 5. Did you smoke during the patient’s gestation?
Father: yes / no
Mother: yes / no
QUESTION 6. If you have since quit, at what age was the patient when you stopped?
Father: ________ years
Mother: _________ years
Results
• N = 142 participants
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Mild hyperopia (+0.25 - +1.75) = 59
Moderate hyperopia (+2.00 - +5.75) = 59
Severe hyperopia (>+6.00) = 15
Myopia = 8
Mean age = 5.29, SD = 2.99, range 0-12y
52% female
21% of mothers smoke; 16% smoked during pregnancy
26% of fathers smoke; 32% smoked during pregnancy
32% have either parent smoking now
38% have a parent smoking during pregnancy
Results
Odds Ratio
95% CI
Significance
Parental Smoking
0.25
0.03-1.99
0.19
Father Smoking
1.77
0.15-20.50
0.65
Father ExSmoking
2.44
0.43-13.95
0.32
Mother Smoking
19.75
1.65-236.51
0.02
Mother ExSmoking
3.90
0.66-23.08
0.13
Gestational Smoking
2.02
0.11-36.15
0.63
Father Smoking
0.42
0.02-8.96
0.58
Mother Smoking
0.11
0.01-0.18
0.07
Father hyperopia
0.94
0.22-3.96
0.93
Father myopia
0.59
0.21-1.68
0.32
Mother hyperopia
2.09
0.56-7.79
0.27
Mother myopia
0.32
0.13-0.80
0.02
Refraction
Adjusted for age & ethnicity
Discussion
In this cohort…
• Gestational smoking is NOT
associated with hyperopia
• Having a mother who is smoking now
increases the odds of moderate to
severe hyperopia (>+3 DS) by nearly
20 fold
• Mother with myopia is protective of a
child having > moderate hyperopia
Discussion
• This is a biased population and a small sample
• A larger study is required, hopefully from
sources other than a private strabismus practice
• Relationship of smoking, hyperopia and
strabismus will need to be explored
If anyone like to contribute patients, please contact
Lionel Kowal ([email protected]) or
Elaine Wong ([email protected])