Eye and Ear Section -- Embryo

Question 1

Cause of coloboma?

Answer 1

Failure of optic fissure to fully close.

Question 2

What is retinochoroidal coloboma?

Answer 2

Localized gap in the retina, usually inferior to the optic disc. Usually bilateral.

Question 3

What is coloboma of the iris?

Answer 3

Defect in the inferior sector of the iris or a notch in the pupillary margin.

Question 4

Developmental cause of detachment of the retina?

Answer 4

Failure of the inner and outer layers of the optic cup to fuse during the fetal period.

Question 5

What diseases are associated with retinal detachment?

Answer 5

Down Syndrome, Marfan

Question 6

What is cyclopia?

Answer 6

Eyes are partially or completely fused, forming a single median eye in a single orbit.

Question 7

Describe the nasal development of a cyclopia patient.

Answer 7

Tubular nose (proboscis) superior to the eye.

Question 8

Why don’t you see a bunch of cyclops people running around?

Answer 8

Because the defects that cause cyclopia are typically incompatible with life.

Question 9

What is microopthalmia?

Answer 9

A congenital group of eye defects that cause very small eyes. The affected side of the face is underdeveloped and the orbit is small.

Question 10

What major eye structure tends to not devleop in severe microopthalmia cases?

Answer 10

The Lens

Question 11

Most common cause of microopthalmia?

Answer 11

Infectious agents that cross the placental membrane in the late embryonic period.

Question 12

What is anophthalmia?

Answer 12

Failure of the eye (or eyes) to develop. Orbit defects are always present. Typically accompanied by severe crainiocerebral defects.

Question 13

Difference between primary and secondaty anophalmos?

Answer 13

Primary – Eye development stops early in week 4. No optic vessicle forms.

Secondary – Forebrain development is suppressed

Question 14

Most neonates have what iris color? When does this change?

Answer 14

Blue/Gray. 6-10 months.

Question 15

Name the pigment containing cells of the iris.

Answer 15

Chromatophores.

Question 16

What determines the color of the iris?

Answer 16

The concentration and distribution of chromatophores.

Question 17

Where is the melanin of a blue eye? Brown eye?

Answer 17

Blue – Only on the posterior surface of the pigmented epithelium.

Brown – Melanin distributed throughout the stroma of the iris

Question 18

Cause of iris heterochromia?

Answer 18

Changes to the sympathetic innervations in the eye.

Question 19

What is congenital anirida? Cause?

Answer 19

Lack or nearly complete absence of the iris. Caused by arrested development at the rim of the optic cup.

Question 20

What gene is associated with anirida?

Answer 20

Pax6

Question 21

How do remnants of the pupillary membrane manifest? Consequences?

Answer 21

Web like strands of connective tissue or vascular arcades over the pupil. Typically the tissue will atrophy and cause no major problems.

Question 22

What if the entire puillary membrane persists?

Answer 22

Congenital atresia of the pupil – no opening, requires surgery or laser treatment.

Question 23

Hyaloid Artery normall becomes…

Answer 23

central artery of the retina

Question 24

Side effect associated in severe cases of hyaloid artery persistence

Answer 24

Micropthalmic eye

Question 25

What is congenital aphakia?

Answer 25

Complete absence of the lens. No lens placode formation in the 4th week. Failure of lens induction by optic vesicle.

Question 26

Cause of heightened intraocular pressure in neonates?

Answer 26

Congenital Glaucoma caused by a drainage problem

Question 27

Potential cause of congenital glaucoma

Answer 27

Failure of the scleral venous sinus to develop or neonatal rubella infection.

Almost ALWAYS CYP1B1 gene associated.

Question 28

What occurs in congenital cataracts?

Answer 28

Lens is opaque and frequently appears grayish white.

Question 29

Potential causes of congenital cataracts?

Answer 29

genetic inheritance, Rubella virus, radiation, congenital galactosemia

Question 30

How will heightened CSF pressure influence the eye?

Answer 30

Slowed retinal venous return, causing papilledema of the optic disc.

Question 31

Cause of congenital ptosis?

Answer 31

Failure of the levator palpebrae to form normally. Possibly also caused by prenatal injury to CNIII.

Can cause loss of vision

Question 32

What is a palpebral coloboma?

Answer 32

Any large defect in the eyelid, typically a notch in the superior. Drying and ulceration of the cornea may result.

Question 33

What is cryptophtalmos?

Answer 33

Congenital absence of eyelids, which causes skin to cover the eyes. No cornea or conjunctiva.

Question 34

Most common cause of congenital deafness

Answer 34

Genetic factors such as a GJB2 mutation

Question 35

If first arch syndrome occurs, what ear structures should be considered?

Answer 35

Malleus and Incus

Question 36

What infection is especially likely do damage the developing cochlea?

Answer 36

Rubella

Question 37

Result of congenital fixation of the stapes? Cause?

Answer 37

Conductive deafness in an otherwise normal ear. Caused by failure of differentiation of the annular ligament.

Question 38

Why is it important to note even minor auricular abnormalities?

Answer 38

Minor defects may be correlated with specific patterns of genetic abnormalities (ex. trisomy 18 or maternal drug use)

Question 39

What causes accessory auricular appendages?

Answer 39

Development of accessory auricular hillocks.

Question 40

Are auricular appendages usually uni- or bi- lateral?

Answer 40

Unilateral

Question 41

What is anotia? What is it associated with?

Answer 41

Absence of the auricle. First Pharyngeal Arch Syndrome, which causes failure of mesenchymal proliferation.

Question 42

What is microtia? What causes it?

Answer 42

Small/rudimentary auricle caused by suppressed mesenchymal proliferation.

Question 43

What are preauricular sinuses/fistulas?

Answer 43

Pit like depressions/sinuses located in the area anterior to the auricle.

Question 44

Cause of atresia of the external acoustic meatus?

Answer 44

Failure of the meatal plug to canalize.

Question 45

Atresia of the external acoustic meatus is typically associated with…

Answer 45

First Arch Syndrome

Question 46

Describe the auricle of a subect without an external acoustic meatus.

Answer 46

Normal.

Question 47

Cause of absence of the external acoustic meatus?

Answer 47

Failure of inward expansion of the first pharyngeal groove and the meatal plug to disappear.

Question 48

What is Congenital Cholesteatoma?

Answer 48

A growth of keratinized epithelial cells retained after birth that can grow and invade neighboring bones.