The Morphological Change of Iris and Ciliary Body in the Korean Fetal Eyes according to Gestational Age

ABSTRACT

PURPOSE: This study was performed to investigate the morphological change of the iris and ciliary body of human eyes during fetal period. METHODS: Under the Registry of Congenital malformation, fetuses were supplied by the Department of Pathology of Seoul National University. We selected 81 eyes enrolled with the gestational age between 8 and 40 weeks, and examined under light microscope. RESULTS: The development of iris and ciliary body began from 12 weeks. During the gestational age 15-18 weeks, marginal sinus and the fold of iris and ciliary body were formed. At the gestational age 18 weeks, the iris sphincter located in front of marginal sinus was certainly distinguished, and the vessels of ciliary body formed. During the gestational age 19-22 weeks the minor folds of ciliary body were formed between the original it. During the gestational age 23-27 weeks marginal sinus was being diminished and dilator muscle was seen. During the gestational age 28-30 weeks the dilator muscle of iris was certainly developed and the longitudinal and circular muscle of ciliary body were distinguished. During the gestational age 34-40 weeks the adultlike appearance of the iris and ciliary body became apparent. CONCLUSIONS: The mesenchymal cells located in the anterior rim of optic cup began to develop after the gestational age 12 weeks. If the develpment of the iris and ciliary body was arrested around the gestational age 15-22 weeks, the congenital malformation of the iris and ciliary body could appear.