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Up to 90% of children with fetal alcohol syndrome have eye abnormalities such as optic nerve hypoplasia and tortuosity of the retinal blood vessels. Because ocular findings are so common, an eye examination can be useful in helping diagnose fetal alcohol syndrome.
Hershey, PA-An ocular examination can help make a diagnosis of fetal alcohol syndrome (FAS), because an estimated 90% of children affected with FAS have eye abnormalities. The most common findings are optic nerve hypoplasia and tortuosity of the retinal vessels. Strabismus also is a typical finding, whereas less frequently reported ocular abnormalities include ptosis, microphthalmos, Duane's retraction syndrome, and DiGeorge syndrome.
Anterior segment anomalies associated with FAS include corneal opacities, cataract, glaucoma, and Axenfeld's and Peters' anomalies, according to Joseph W. Sassani, MD, professor of ophthalmology and pathology, Penn State College of Medicine, Hershey, PA.
According to Dr. Sassani, multiple pathogenic mechanisms have been postulated for Peters' anomaly. Evidence appears to support the theory of delayed separation of the lens from the surface ectoderm during embryogenesis in alcohol-exposed fetuses.
Describing FAS and its ocular findings, Dr. Sassani explained that the spectrum of ocular and periocular abnormalities associated with FAS includes short palpebral fissures, telecanthus, epicanthus, and blepharoptosis. Decreased visual function, refractive errors, and strabismus also are a frequent result.
Although warnings about alcohol consumption by prospective parents date to antiquity, the first formal report calling attention to the increased incidence of gross retardation, mental deficiency, and congenital anomalies in children of alcoholic parents did not appear until 1967. Additional characteristic morphologic and functional findings subsequently were described, leading to the coining of the term fetal alcohol syndrome and an agreed-on definition.
The Fetal Alcohol Study Group, based on a review of 245 cases, established specific criteria for the diagnosis of FAS in 1980. The criteria required clinical findings from each of three categories: prenatal and postnatal growth retardation, central nervous system abnormalities, and characteristic facial abnormalities. The criteria required that the facial findings of FAS must be distinguished from those of other congenital syndromes.
Current diagnosis criteria
The original criteria have been updated, Dr. Sassani said. Diagnosis currently requires the following indications: documentation of all three characteristic facial abnormalities (smooth philtrum, thin vermilion, and small palpebral fissures); documentation of growth deficits; and documentation of CNS abnormality.
FAS is classified among the continuum of Fetal Alcohol Spectrum Disorders, including partial FAS and alcohol-related neurodevelopmental disorder (ARND). Focusing on FAS, Dr. Sassani explained that it could be accompanied by multiple neurologic and neuropsychiatric disorders, such as attention deficit disorder.
"Follow-up studies of affected children demonstrate decreased prominence of the dysmorphic facial features and improved neurologic performance with increasing age. Nevertheless, major handicaps, particularly attributable to hyperactivity and distractibility, persist into adulthood," he said.
FAS is one of the most common developmental disabilities in the United States and the leading known cause of mental retardation, Dr. Sassani said. It is believed to occur in 0.5 to 2.0/1,000 live births, although a higher estimate of 9.1/1,000 live births has been reported if FAS and ARND are included in the calculation. Approximately 12,000 new cases are reported in the United States each year. Native Americans have higher rates of alcohol use, frequency of use, and FAS compared with other ethnic groups; the estimated incidence in this population is 10.3/1,000 live births. As in the United States, FAS is the major cause of mental retardation elsewhere in the Western world.
"The epidemiology of FAS can involve inter-relationships between multiple populations at different ages, including fetuses, adolescents, and adults, so that alcohol exposure at any of these developmental stages increases the probability of exposure at others," Dr. Sassani added. "These circular relationships have been called the alcoholism generator, which helps perpetuate the FAS cycle."