Eye Development Flashcards
When is the critical period for fetal eye development?
Weeks 4-7
What embryonic layers give rise to the eye?
Neuroectoderm
Surface ectoderm
Mesoderm/Neural Crest
What part of the brain does the eye originate from?
Diencephalon
What do the rims of the optic cup give rise to?
Iris and ciliary body
What muscles are the only muscles in the body to arise from neuroectoderm?
Dilator and Constrictor pupillae muscles
What embryonic layer gives rise to the stroma of the iris?
Neural Crest
What embryonic layer gives rise to the epithelium of the iris and the ciliary body?
Neuroectoderm
What embryonic layer gives rise to the smooth muscle cells of the ciliary body?
Mesoderm
What congenital disorders can predispose a patient to having separation of the pigmented and neural retina?
Down’s syndrome
Marfan’s syndrome
Redevelopment of the intraretinal space comes from separation of what layers?
Neural retina and pigmented retina
Defects in the Pax6 gene can have what result on the eye?
Aniridia
Arrested development of what optic structure during the 8th week can result in aniridia?
Rim of optic cup
What embryonic layer gives rise to the lens of the eye?
Surface ectoderm
What structures of the lens are responsible for its transparent nature?
Primary lens fibers - columnar epithelium with dissociated nuclei
What optic structure do cataracts affect?
Lens
Maternal rubella infection between 4-7 weeks gestation can have what effect on fetal eye development?
Congenital cataracts (vulnerable lens development)
Congenital glaucoma
A 3 week old patient presents with congenital cataracts. He is being breastfed. What is the most likely diagnosis?
Congenital Galactosemia - accumulation of galactose from milk because of enzyme deficiency
What layer of meninges is the sclera continuous with?
Dura
What layers of meninges is the choroid continuous with?
Pia and arachnoid
What optic structure does the pupillary membrane arise from?
Sclera
When does the pupillary membrane degenerate during fetal eye formation?
Week 26
What is the embryonic origin of primary vitreous humor?
Choroid (mesenchyme/NCC)
Defects in what gene can cause congenital glaucoma?
CYP1B1
Elevated intraocular pressure can place patients at risk for what disorder?
Congenital glaucoma
Abnormal neural crest migration to form the scleral venous sinus results in an inability to drain what ocular fluid?
Aqueous humor
What is the embryonic origin of the extra-ocular muscles?
Prechordal mesenchyme
What embryonic artery gives rise to the central retinal A.?
Proximal portion of the Hyaloid A.
What embryonic layer gives rise to the blood vessels of the eye?
Mesoderm
What does the Hyaloid A. supply during fetal eye development?
Inner layer of optic cup
Lens vesicle
Optic cup mesenchyme
What embryonic arteries do the ciliary arteries give rise to?
Choroidal vessels
When do the choroidal vessels develop during fetal eye development?
15th week
What nourishes the eye when the choroidal vessels degenerate?
Aqueous humor
A patient presents to the ophthalmologist for a checkup. On examination, the patient’s left eye is smaller than usual and has a worm-like structure on the inside? What is the most likely cause of this?
Persistence of the distal portion of the Hyaloid A.
What is the optic vesicle’s relationship to the optic nerve?
Provides the template and pathway for optic nerve
DOES NOT BECOME OPTIC NERVE
What space will papilledema collect in?
Subarachnoid space of the meninges covering the optic vessels
A patient presents with a key-lock appearing pupil. What is their most likely diagnosis?
Coloboma
What is the embryological cause of coloboma?
Optic fissure fails to close completely, leaving a gap in the iris
What is the genetic inheritance of coloboma?
Autosomal dominant
