The applied anatomy of the eye

Question 1

List the muscles connected to the eye and their impact on the pupil when contraction occurs.

Answer 1

Medial rectus - Pupil adduction
Lateral rectus - Pupil abduction
Superior rectus - Pupil moves superiorly
Inferior rectus - Pupil moves inferiorly
Superior oblique - Pupil moves inferior and laterally
Inferior oblique - Pupil moves superior and laterally

Question 2

Describe the sclera of the fibrous layer.

Answer 2

White
Maintains shape of eyeball
Collagen

Question 3

What is the limbus?

Answer 3

The junction between the sclera and the cornea.

Question 4

What is a scleral buckle and what its purpose?

Answer 4

A band that wraps around the eyeball to prevent retinal detachment.

Question 5

How does scleral icterus present in patients?

What disease state can this be indicative of?

Answer 5

Yellow eyes.
Excess serum bilirubin.
Hepatic failure and jaundice.

Question 6

What is the conjunctiva?

What is conjunctivitis?

Answer 6

The tissue that lines the inside of the eyelids and covers the sclera.
Blood vessels of the sclera dilate.

Question 7

What is the cornea?

What is its function?

Answer 7

The transparent layer forming the front of the eye.

It allows light to pass through towards the lens.

Question 8

What is a corneal abrasion?

Answer 8

Scratched cornea. Recovers within a few days.

Question 9

What is keratoconus?

Answer 9

Cornea is thinner than it should be which leads to a buldge and affects vision.

Question 10

What is Fuch’s endothelial dystrophy?

Answer 10

Inherited condition.
Progressive visual blurring.
Patients have less endothelial cells in the inner cornea.
So the cornea is not dehydrated and there is abuild up of fluid.

Question 11

What are the three layers of the eye?

Answer 11

Fibrous
Vascular
Inner

Question 12

Explain the innervation of the muscles attached to the exterior of the eye.

Answer 12

Superior oblique - Trochlear nerve (IV)
IO, MR, SR, IR - Occulomotor nerve (III)
Lateral rectus - Abducent nerve (VI)

Question 13

What is the choroid?

Answer 13

Vascular layer between the retina and the sclera.

Question 14

What is the ciliary body?
Where is it located?
Which nerve innervates the ciliary muscle?

Answer 14

Comprised of the ciliary muscle and the ciliary epithelium.
It is between the anterior chamber and the vitreous humour.
Occulomotor nerve (III)

Question 15

What is the lens?

Answer 15

Transparent, onion like structure between the aqueous and vitreous humour.

Question 16

What is cataract surgery?

Answer 16

Inside of the lens is removed by phacoemulsification and is replaced with a clear, artificial alternative.

Question 17

What are the two types of muscle in the iris and how are they innervated? What effect does this have on the pupil?

Answer 17

Circular muscle - Parasympathetic innervation, occulomotor nerve. Pupil constriction
Radial muscle - Sympathetic innervation, superior cervical ganglion. Pupil dilatation.

Question 18

What is horners syndrome?

Answer 18

Sympathetic neuron damage.

Results in pupil constriction and a drooping eyelid.

Question 19

What do mydriatic medications do?

Answer 19

Cause pupil dilation

Question 20

What is the optic disc?

Why does this cause a blind spot?

Answer 20

The point of exit for axons leaving the eyeball.

Because there are no rods and cones.

Question 21

What is the macula?

What structures is it comprised of?

Answer 21

Section of the retina directly behind the lens.

Comprised of the fovea (highest cone density), parafovea and perifovea. Moving from the centre outwards respectively.

Question 22

What is AMD? How does it affect your vision?

Answer 22

Age-related macula degeneration.

Donut vision

Question 23

What is retinitis pigmentosa? How does it affect your vision?

Answer 23

Degeneration of cells in the retina.

Tunnel vision.

Question 24

What are the two chambers of fluid in the eye?

Answer 24

Aqueous humour (anterior and posterior chambers) and the vitreous humour.

Question 25

What causes glaucoma?

Answer 25

Buildup of fluid in the aqueous humor. Causes damage to optic nerve.