Eye Development

Question 1

Three embryonic sources of the eye

Answer 1

Neuroectoderm
Surface ectoderm
Mesoderm/neural crest

Question 2

Origin of the eye

Answer 2

Prosencephalon

Question 3

Neuroectoderm forms which parts of the eye

Answer 3

Retina- neural and pigmented portions
Iris- epithelial layer, smooth muscle
Ciliary body- epithelial layer

Question 4

Detachment of retina

Answer 4

Pigmented and neural retina separate

Question 5

Aniridia

Answer 5

Lack of iris tissue or complete absence of the iris
Results from- glaucoma, cataracts and other eye abnormalities
Pax6 gene mutation

Question 6

Surface ectoderm forms

Answer 6

Lens- production is induced by optic cup

Epithelium of cornea

Question 7

Congenital cataracts

Answer 7

Lens is opaque and appears grayish white

Caused by genetics, rubella, radiation, enzyme deficiency (congenital galactosemia)

Question 8

Mesenchyme/neural crest cells form

Answer 8

Sclera
Stroma of cornea and iris
Choroid-inner layer of pia and arachnoid, vascular
Ciliary body- stroma and ciliary muscle

Question 9

Anterior chamber

Answer 9

Aqueous humor resorbed by scleral venous sinus

Question 10

Posterior chamber

Answer 10

Aqueous humor secreted by ciliary epithelium

Question 11

Vitreous vs aqueous humor

Answer 11

Vitreous humor is primary from choroid

Aqueous humor is made by ciliary body

Question 12

Congenital glaucoma

Answer 12

Elevated intraocular pressure

Caused by genetics (85% of cases) CYP1B1 gene, rubella

Question 13

Extra-ocular muscles derived from

Answer 13

Prechordal mesenchyme

Question 14

Hyaloid artery

Answer 14

Branch of ophthalmic artery
Supplies inner layer of optic cup, lens vesicle, mesenchyme in optic come
Become the central artery

Question 15

Optic nerve

Answer 15

Two layers of neuroblasts- rods/cones, ganglion cells
Fibrous layer- axons forming optic nerve
Fibers grow through inner part of optic stalk, cavity becomes obliterated and hyaloid artery is incorporated

Question 16

Papilledema

Answer 16

Increased intracranial pressure slows venous return from retina, causing fluid accumulation of the optic disc
Edema occurs because the retinal vessels are covered by the meninges and lie in the extension of the subarachnoid space

Question 17

Rubella virus

Answer 17

Congenital infection, causes cardiac and great vessel abnormalities, sensorineural deafness, cataracts, microphthalmos, glaucoma, pigmented retinopathy, neonate bleeding

Question 18

Taxoplasma gondii

Answer 18

Congenital infection, causes microphthalmia, hearing loss

Question 19

Venezuelan equine encephalitis virus

Answer 19

Congenital infection, causes microphthalmia

Question 20

Varicella virus

Answer 20

Congenital infection, causes cataracts, microphthalmia, optic atrophy