This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ocular Embryology& Anatomy, Subject name: Ophthalmology
Fetal /choroidal fissure is closed by which week of gestation 
Select and explain. 
A. 3rd week, B. 4th week, C. 6th week, D. 8th week
C: 6th week
Answer: C: 6th week 
Explanation: Fetal fissure is closed by 6th week Failure to close can lead to formation of coloboma(eg- pear shaped coloboma of iris,chorioretinal coloboma i)