Maria Stamos, MAppSc, GradDip (Neurosciences), DipAppSc(Orth), DOBA
Linda Santamaria, MAppSc, DipAppSc(Orth), DOBA
Cathy Mccarty, PhD, MPH
Catherine Devereux, MAppSc, Bed, DipAppSc(Orth), DOBA
Ian Story, PhD, BBSc(Hons)
Purpose: To identify any common prenatal maternal factors influencing pregnancy that may predispose infants to develop infantile strabismus.
Methods: A case control study was designed to evaluate the risk factors for strabismus. A set of exclusion and inclusion criteria was established for the cases and controls. The participating practices included fourteen private practised and three public hospitals throughout Victoria. Infants with infantile strabismus were recruited to the study on a voluntary basis as they presented to the various ophthalmic practices and hospitals. The control group participants were obtained from five Maternal and Child Health Centres. The mothers of the infants were given a pilot-tested questionnaire to complete. The questionnaire was made up of general questions relating to the mother and infant, ‘masked’ questions and specific questions related to the usage of alcohol, drugs and tobacco by the mother during pregnancy.
Results: This study included 43 infants with strabismus and 100 controls. The strabismus group consisted of 37 cases of infantile esotropia and 6 cases of infantile exotropia. There were no known neurological deficits in either group. All infants were less than 12 months of age. There were several significant differences between the two groups. The most significant finding was that of parity, with 19% of infants in the strabismus group being the mother’s first born, while in the control group 51% of infants were the mothers first born (c_13.0,df=1, p=0.0003). More mothers from the strabismus group took medication prior to pregnancy compared with the control group, the incidence being 14% and 5% respectively (c_=3.57, df=1, p=0.06). More of the mothers in the strabismus group (63%) had a history of ever smoking (that is , past or current smoker) compared to the control group (47%) (c_=3.00, df=1, p=0.08) and more lived with a partner who smoked (40%) compared to the control group (22%) (c_=4.4, df=1, p=0.04). Strabismus in infants was not significantly associated with a family history of strabismus (p>0.05).
Conclusion: In this study, it appears that exogenous factors such as maternal smoking and medication usage, as opposed to endogenous factors, such as maternal and family ocular history and maternal medical conditions present prior to and during pregnancy, may have been more prominent factors in the development of infantile strabismus.