- Describe the development of the eye
- The eye develops between the 3rd and 10th week of embryonic development
- Optic grooves develop from the neural folds bilaterally
- During the 4th week when the folds close to form the neural tube, optic vesicles appear at the base of the forebrain
- The optic vesicles contact the surface ectoderm and induce it to differentiate into the lens placode
- The lens placode invaginates to form the lens pit. At the same time, the optic vesicles invaginate to form the optic cup.
- The inferior surface of the optic cup has a central groove known as the choroidal fissure which allows the hyaloid artery to enter and supply the eyes.
- Derivatives
- Surface ectoderm – lens, corneal epithelium and eyelids
- Neuroectoderm – retina, ciliary body, iris and optic nerves
- Mesoderm or neural crest cells – sclera, corneal endothelium and stroma, blood vessels, muscles and vitreous
- Describe the congenital anomalies associated with the development of the eyes
- Coloboma idris: Occurs when the choroid fissure fails to close. Manifests as a keyhole-shaped defect of the iris
- Congenital cataracts: Maternal Rubella or Genetics predispose to forming cataracts
- Persistent hyaloid artery: The hyaloid artery can persist to form a cord or cyst
- Micropthalmia: This is a small eye. It is associated with other abnormalities such as facial cleft and trisomy 13.
- Anopthalmia: Absence of the eye
- Congenital aphakia: Absence of the lens
- Aniridia: Absence of the iris
- Cyclopia : Occurs when the midline tissue is lost, as in Holoprosencephaly
- Synopthalmia: Fused eyes
