Microphthalmos with Cyst: Usually unilateral in nature, microphthalmos with cyst is an entity cause by failure of the choroidal fissure to close in the embryo, resulting in the formation of a small eye. Through the choroidal coloboma, a cystic expansion develops and extends posteriorly into the orbit. The cyst contains proliferated, dysplastic, neuroectodermal tissue. Back to Orbit