[Microphthalmos and its pathogenic classification].

Congenital microphthalmos is a common malformation encountered clinically. Microphthalmos in adults is here defined as eyes whose axial length is below 20.4 mm in males and 20.1 mm in females; in under 14-year-old children, it is eyes at least 3 square root of 2/3 below the mean for age-similar controls. Experimental animals with hereditary microphthalmos have been widely investigated, and many environmental factors given to pregnant animals frequently induce microphthalmos. In both clinical and experimental microphthalmos, there are conspicuous variations in size, and various kinds of ocular and systemic complications. Recently, fetal alcohol syndrome produced by alcohol intake during pregnancy has been reported. In this syndrome, microphthalmos is one of the important symptoms. Experimentally, microphthalmos also developed at a high incidence among mouse fetuses whose mothers were given ethanol during pregnancy. The present investigator established a preliminary etiological classification of microphthalmos in 1984. In this paper summing up newly obtained results, the relationship to neural crest cells and histochemical changes of glycosaminoglycan molecular species, the author presents a final pathogenic classification of microphthalmos, which consists of developmental disturbance of the optic vesicle, malformation of the optic cup, mesenchymal dysgenesis of the anterior ocular segment, maldevelopment of the lens, maldevelopment of the vitreous, faulty closure of the embryonic fissure and developmental disturbance of the wall of eyeball.