Physiology

Question 1

Rate of eyelash regrowth

Answer 1

2 wk if cut

2 Mo ifepilated

Question 2

Relative location of recti to limbus

Answer 2

Spiral of Tillaux: MILS

Medial (5.5mm)
Inferior (6.5mm) - temporal insertion is more posterior
Lateral (6.9mm)
Superior (7.7mm) - temporal insertion is more posterior

Question 3

Drainage of post-tarsal blood

Answer 3

Orbital veins:

• superior ophthalmic vein
• inferiorly ophthalmic vein

Deep facial vein

Pterygoid plexus

These empty to jugular

Question 4

Drainage of pre-tarsal blood

Answer 4

Superficial veins of the face

Medially: angular vein
Laterally: superficial temporal vein

Question 5

Blood supply to optic nerve: prelaminar

Answer 5

Short posterior ciliary and recurrent choroidals arteries

Question 6

Blood supply to optic nerve: laminar

Answer 6

SPCA, branches of the circle of Zinn

Question 7

Blood supply to optic nerve: retrolaminar

Answer 7

Pial vessels

SPCAs

Question 8

Blood supply to optic nerve: intraorbital

Answer 8

Distally/anteriorly: Central Retina Artery, pial vessels, branches of the ophthalmic artery

Proximally/posteriorly: pial vessels, branches of the ophthalmic artery

Question 9

Blood supply to optic nerve: intracanalicular

Answer 9

Ophthalmic artery

Question 10

Blood supply to optic nerve: intracranial

Answer 10

Ophthalmic artery, ICA

Question 11

Rate of aqueous production

Answer 11

2uL/min