Question: how many days after fertilization do the eyes begin to develop?
Answer: The human eye begins to develop during the 17th day of gestation. Mesoderm cells, the middle layer of the blastoderm, and ectoderm cells, the outer layer of the blastoderm, form the eye fields in the neural area of the embryo. Optic vesicles develop in the eye fields and in five days, infold to form the optic cup.