Ocular involvement in fetal alcohol spectrum disorder: a review

Fetal Alcohol Syndrome (FAS), the most severe manifestation of Fetal Alcohol Spectrum Disorder (FASD) is considered the leading non-hereditary cause of mental retardation and neurological deficit in the Western world. There lie a huge associated human cost to both FASD victims and their families and a considerable financial burden. This problem is being tackled on many fronts including community awareness programs, biomarker development for fetal alcohol exposure, research into preventative treatments and the development of more robust diagnostic systems for the early detection of FASD. Although ethanol can affect many of the major systems of the body, the eye is a primary target. Ocular aberrations including optic nerve hypoplasia, tortuosity of retinal vessels, coloboma and microphthalmia are frequently observed in children diagnosed with FAS. In this regard, ocular involvement in FAS has gained importance, particularly in relation to early diagnosis and identification of FAS. Furthermore, our considerable knowledge of the molecular mechanisms underlying eye development has provided a powerful tool for the investigation of the teratogenic actions of ethanol. In this review, we initially provide an overview of FASD in terms of historical background, epidemiology and current status. Next, we explore the role of ocular involvement in FASD and the use of eye measurements in the diagnosis of FAS. Lastly, we review how current knowledge of early eye development can be used to gain new insights into the molecular mechanisms of ethanol teratogenicity with particular reference to the sonic hedgehog pathway.