9 - Head & Neck - The Eye Flashcards Preview

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Flashcards in 9 - Head & Neck - The Eye Deck (30)
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1
Q

Which bones form the orbit?

A
  • Sphenoid bone
  • Ethmoid bone
  • Frontal bone
  • Lacrimal bone
  • Maxillary bone
  • Zygomatic bone
2
Q

List the boundaries of the orbit:

A
Apex = Optic canal
Roof = Frontal + Sphenoid
Floor = Maxillary + Zygomatic
Lateral = Zygomatic + Sphenoid
Medial = Lacrimal + Ethmoid + Maxillary + Sphenoid
3
Q

Which wall of the orbit is the weakest?

A

Base of orbit

4
Q

Name the tissue of the eye to which the extra-ocular muscles attach to:

A

Sclera

5
Q

Why does the eye appear red if patient has conjunctivitis? Why does conjunctivitis not affect the iris or pupil?

A
  • Blood vessels in the conjunctivae dilate due to inflammation
  • Conjunctivae covers sclera up to the cornea (does not cover pupil/iris)
6
Q

Which structures of the eye are avascular? How do they recieve nutrients?

A
  • Lens
  • Cornea

via Aqueous humour

7
Q

Name the tissues which form the outer tough layer of the eyeball:

A
  • Sclera

- Conjunctiva

8
Q

Name the tissues which form the middle layer of the eyeball:

A
  • Choroid
  • Ciliary body
  • Iris
9
Q

Which structure makes up the inner layer of the eyeball?

A

Retina

10
Q

Which layer of the eyeball contains a rich network of blood vessels?

A

Middle layer (mainly in choroid)

11
Q

Name the 3 chambers of the eyeball, and the fluid which fills each:

A

1) Anterior chamber - Aqueous humour
2) Posterior chamber - Aqueous humour
3) Vitreous chamber - Vitreous humour

12
Q

How does the anterior chamber of the eye communicate with the posterior chamber?

A

Through the pupil

13
Q

Which structures of the eye secrete aqueous humour?

A
  • Ciliary body

- Ciliary processes

14
Q

What are the roles of the ciliary body?

A
  • Controls thickness and focus of lens
  • Varies opening of trabeculae meshwork
  • Secretes aqueous humour
15
Q

Describe the drainage of aqueous humour into the venous system:

A
  • Through Irido-corneal angle

- Into canal of Schlemm via trabecular meshwork

16
Q

Name the 3 canals which open into the orbit, and which bone they lie in:

A
  • Superior orbital fissure
  • Inferior orbital fissure
  • Optic canal

= Sphenoid bone

17
Q

Which structures run in the optic canal?

A
  • Optic nerve

- Ophthalmic artery

18
Q

Which structures run in the superior orbital fissure?

A
  • Oculomotor nerve (sup. + inf. branches)
  • Trochlear nerve
  • Abducens nerve
  • Ophthalmic nerve (frontal, lacrimal + nasociliary branches)
  • Superior ophthalmic vein
19
Q

Which structure runs in the inferior orbital fissure?

A
  • Inferior ophthalmic vein
20
Q

What is a ‘blow-out fracture’?

A

Fracture of orbit, usually medial wall + floor

21
Q

What is Reiter’s syndrome?

A

Conjunctivitis, arthritis + urethritis

- Autoimmune reactive arthritis due to bacterial infection

22
Q

What is the classical presentation of an Oculomotor nerve lesion?

A
  • Ptosis
  • Fully dilated pupil
  • ‘Down-and-out’ eye
23
Q

Why may someone with a facial nerve palsy have to consistently dab eye due to constant weeping?

A

Paralysis of orbicularis oculi
= Inferior eyelid pulls away, exposing cornea
= Constant irritation
= Increased lacrimal secretion

24
Q

What is cataracts? Who does it commonly affect?

A

Opacification of the lens
= reduced vision
= reduced acuity
= reduced contrast sensitivity

Diabetics, smokers, elderly

25
Q

What is Presbyopia?

A

The natural long-sightedness occurring with age, due to loss of elasticity of lens

26
Q

How does retinal detachment present? What causes these symptoms?

A

Blurring of vision, black dots/streaks, sudden flashes of light

Retina detaches from choroid (which contains blood supply), leading to avascular necrosis of retina.

27
Q

Name the most common type of glaucoma:

A

Open-angle glaucoma

28
Q

What is open-angle glaucoma?

A

Increased intra-ocular pressure due to blockage within trabecular meshwork of eye = damaged optic nerve
Develops slowly and painlessly.
Signs = optic disc cupping, loss of visual field

29
Q

What is the treatment for open-angle glaucoma?

A
  • Eyedrops to reduce aqueous humour production: beta-blockers ie Timolol
  • Surgery (trabeculectomy)
30
Q

What is closed-angle glaucoma?

A

Rapid increase in intracranial pressure due to narrowing of irido-corneal angle