SCLERA

Question 1

WHAT IS SCLERA DERIVED FROM?

Answer 1

MESENCHYME OUTSIDE OPTIC CUP

Question 2

WHERE DOES SCLERA FIRST FORM?

Answer 2

NEAR FUTURE INSERTION OF RECTI MUSCLES

Question 3

SCLERA

Answer 3

• tough, white outer layer of eyeball
• continuous with cornea
• anteriorly covered by bulbar conjunctiva
• inner surface in contact with choroid
• perforated by nerves + BV’s

Question 4

SCLERA FUNCTIONS

Answer 4

• protects against trauma + mechanical displacement
• preserves shape of eyeball
• provides rigid insertion for EOM
• divided into ant. + post. portions at equator

Question 5

LAYERS OF SCLERA

Answer 5

1. episcleral tissue
2. scleral proper
3. lamina fusca

Question 6

EPISCLERAL TISSUE

Answer 6

• thin tissue overlying sclera

- dense vascular layer of connective tissue

Question 7

SCLERAL PROPER

Answer 7

• avascular

- interlaced bundles of collagen fibres

Question 8

LAMINA FUSCA

Answer 8

• innermost layer of sclera
• contains collagen fibres + melanocytes
• attached to choroid by collagen fibres
• brown due to pigmented cells

Question 9

ANTERIOR SCLERAL COAT

Answer 9

• tenons capsule partly covers ant. sclera

- thin fibrous membrane that envelopes eyeball from optic nerve to limbus

Question 10

SCLERAL SPUR

Answer 10

collagen containing structure, protrusion of sclera into ant. chamber

Question 11

LAMINA CRIBROSA

Answer 11

• mesh like structure behind optic disc in sclera

- allows optic nerve fibres to pass through + acts as a pressure barrier