Ocular: Sclera And Episclera 2

Question 1

How are Corneal lamellae stacked?

Answer 1

Perpendicularly on top of each other

Question 2

How are collagen arranged in sclera?

Answer 2

Random interweaving to help with strength and flexibility

Question 3

Why does sclera look opaque?

Answer 3

Because light is scattered

Question 4

Are there more or less collagen fibroblasts in the sclera when compared to the cornea?

Answer 4

Less

Question 5

What are the gags in the sclera? And are there more of less in he sclera compared to cornea?

Answer 5

-dermatan sulfate and chondroitin sulfate
-less gags bc less hydrated

Question 6

What makes up the elastin in the sclera?

Answer 6

Fibrillin

Question 7

What does a mutation in fibrillin cause?

Answer 7

Marfan’s syndrome which is thinning/stretching of the sclera

Question 8

What can thinning/stretching of the sclera lead to in the eye?

Answer 8

High myopia and potentially posterior staphyloma

Question 9

An OCT of a very myopic person would be ___ shaped

Answer 9

U shaped

Question 10

Collagen synthesis in myopes __________

Answer 10

Decreases

Question 11

An eye is myopic typically due to…

Answer 11

Longer axial length

Question 12

In myopia scleral ________ are lost

Answer 12

Proteoglycans

Question 13

OVERALL in myopia the sclera _____ and ________

Answer 13

Thins and weakens

Question 14

Sclera is thin and distensible until age ___

Answer 14

3

Question 15

If you have a thin sclera, and increase in IOP can cause…

Answer 15

Stretching of the sclera and enlarged eye (bupthalmos)

Question 16

Why does sclera become more rigid as you age?

Answer 16

Corneal cross-linking occurs

Question 17

Color of sclera in newborns:

Answer 17

Blue/grey

Question 18

Color of sclera as you increase in age

Answer 18

Mild yellowish hue due to lipid degeneration

Question 19

Color of conj/sclera due to liver disease

Answer 19

Yellow

Question 20

Color of sclera in osteogenesis imperfecta

Answer 20

Blue

Question 21

Osteogenesis imperfecta is a deficiency in what? What does it cause?

Answer 21

-Type I collagen
-causes the sclera to not be opaque and uveal structures become visible

Question 22

Ehlers-danlos syndrome

Answer 22

-Hereditary connective tissue disorder that manifests clinically with skin hyper-elasticity, hyper-mobility
-casues blue sclera

Question 23

Melanocytosis

Answer 23

Excessive melanocytes in skin and parts of the sclera

Question 24

Oculodermal melanocytosis causes an increased risk for _________

Answer 24

Melanoma

Question 25

Scleral hyaline plaques are caused by:

Answer 25

-UV exposure along with wear and tear from nearby rectus insertions -causes scleral thinning (blue/grey color)

Question 26

Innervation of anterior sclera

Answer 26

LPCN

Question 27

Innervation of posterior sclera:

Answer 27

SPCN

Question 28

Vascular supply of sclera:

Answer 28

Post., Middle, and ant aperatures

Question 29

Where does sclera receive nutrients?

Answer 29

Episcleral and choroidal capillary beds

Question 30

Functions of the sclera:

Answer 30

-provide globe with internal support and resistance -provide attachment for EOM insertions into globe

Question 31

ROC of the sclera

Answer 31

12mm

Question 32

ROC of the cornea

Answer 32

8mm

Question 33

The LARGER the radius of sclera =

Answer 33

The flatter

Question 34

The SMALLER the radius of sclera =

Answer 34

The STEEPER

Question 35

External scleral sulcus:

Answer 35

-transition between flatter sclera den steeper cornea **essentially the limbus

Question 36

Aqueous drainage structures within the internal scleral sulcus:

Answer 36

-trabecular mesh work -canal of schlemm

Question 37

Interna scleral sulcus is bounded anteriorly by _____

Answer 37

Cornea

Question 38

Internal scleral sulcus bounded posteriorly by ___________

Answer 38

Scleral spur

Question 39

Scleral spur:

Answer 39

inner sclera that contributes and continues to anterior chamber angle

Question 40

What is scleral spur continuous with anteriorly?

Answer 40

Trabecular meshwork

Question 41

Posteior scleral spur is the origin of the…

Answer 41

Longitudinal ciliary muscle fibers

Question 42

Lamina fusca is an inner scleral layer that contains: (cell types)

Answer 42

-many Melanocytes -MORE elastin fibers

Question 43

Lamina fusca is the transition zone between…

Answer 43

Sclera and ciliary body/choroid

Question 44

Lamina fusca contains what?

Answer 44

Suprachoroidal and supracilairy space

Question 45

Suprachoroidal injection movement:

Answer 45

drug moves within space posteriorly then inward to the retina

Question 46

Lamina cribrosa:

Answer 46

-meshwork of connective tissue that optic nerve axons and central retinal vessels pass though

Question 47

Lamina cribrosa is the _________ part of the sclera

Answer 47

Thickest

Question 48

Lamina cribrosa is ________ interwoven into a combination of different _____________

Answer 48

Elastin, collagen types

Question 49

Where are the retinal ganglion cells damaged in glaucoma?

Answer 49

Lamina cribrosa

Question 50

Glaucoma:

Answer 50

increased IOP that causes posterior bowing or thinning as well as pore enlargement and focal defects in lamina cribrosa

Question 51

If glaucoma is not treated, what happens?

Answer 51

collapse of lamina cribrosa