Incomplete closure of embryonic fissure
Faulty migration of neural crest cells
Exuberant proliferation of glial tissue
Abnormal retinal differentiation
Answer: A. Incomplete closure of embryonic fissure
Explanation: Incomplete closure of embryonic fissure The patient shown has a large chorioretinal coloboma, which is due to incomplete closure of the embryonic fissure. These types of colobomas may involve the optic nerve, choroid, retina, and iris. Faulty migration of neural crest cells results in anterior segment dysgenesis. A morning disc anomaly has abnormal proliferation of glial tissue. Abnormal retinal proliferation can result in retinal dysplasia.