A 3 month old infant was brought to the Opthalmology OPD by her mother,as she noticed that pa of the iris in the baby&;s right eye was missing. Examination revealed a defect in the inferior region of iris and pupillary region which gave it a characteristic keyhole appearance. Which of the following mechanisms during the embryonic development will most likely lead to the given condition ?

Failure of the choroid fissure to close in distal pa results in cleft of the iris known as colomba iris There is a small gap in the inferior surface of the optic cup known as choroid fissure. This fissure allows the hyaloid vessels to reach the inner chamber of the eye During the normal development of eye, the distal pa of hyaloid aery degenerates. The choroid fissure then fuses and this makes the mouth of the optic cup into a round opening. Ref: Inderbir Singh Human Embryology 11 e pg 325,327.