Clinical evaluation of posterior embryotoxon in one institution.

To elucidate the pathogenesis of posterior embryotoxon, we estimated its incidence in our clinic and evaluated its associated ocular and systemic anomalies. Slit-lamp and gonioscopic examinations were performed on 440 randomly selected patients at Nagoya City University Hospital over a 10-month period. Posterior embryotoxon was detected in 107, 50 bilateral and 57 unilateral, cases (24.3%). Twelve (11.2%) of the 107 cases had open-angle glaucoma. Accompanying ocular anomalies included six cases of sclerocornea, two each of persistent pupillary membrane and familial exudative vitreoretinopathy, and 1 each of melanocytoma of the optic nervehead, choroidal nevus and subconjunctival dermoid cyst. Associated systemic anomalies included three cases of Alagille syndrome, two of congenital biliary atresia, and one each of congenital facial palsy with microtia, congenital adrenal hyperplasia, empty sella syndrome, Hirschsprung disease and Wilson disease. Many of these ocular and systemic anomalies were caused by the maldevelopment of neural crest cells. Patients with posterior embryotoxon should be examined for the possible presence of open-angle glucoma and for ocular and systemic anomalies related to maldevelopment of neural crest cells.