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 Mar;42(3): –1-week old chicks, injected with nicotinic antagonists – Chlorisondamine & mecamylamine –Inhibition of ocular growth and shifting refraction toward hyperopia

Background Childhood myopia and parental smoking. Saw SM, Chia KS, Lindstrom JM, Tan DT, Stone RA Br J Ophthalmol Jul;88(7): –N=1334, 8-11 yo school children –Maternal smoking is suggestive of being associated with hyperopic refraction in children (p=0.03; but only 1.7% of mother 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 Oct;47(10): –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 Apr;115(4): –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 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

Results N = 142 participants –Mild hyperopia ( ) = 59 –Moderate hyperopia ( ) = 59 –Severe hyperopia (>+6.00) = 15 –Myopia = 8 Mean age = 5.29, SD = 2.99, Range 0-12yo 52% female 21% mother smoke; 16% smoked during pregnancy 26% father smoke; 32% smoked during pregnancy 32% have either parent smoking now 38% have parent smoking during pregnancy

Results Adjusted for age & ethnicity

Discussion 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 folds Mother with myopia is protective of a child having > moderate hyperopia

Discussion This is a biased population and a small sample Larger study will be 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 Elaine Wong