The Orbit

Question 1

What is the thin portion of the medial wall of the orbit called?

What strengthens it?

What else is a weak portion?

Answer 1

Lamina papyracea

Ethmoid air cells

Floor of orbital

Question 2

In an orbital blow out fracture, what will you see in terms of eye movements?

Why?

Why will you have anaesthesia over the affected check upper teeth and gums?

Answer 2

No upwards gaze on affected side

Extra ocular muscles and soft tissue become trapped at the fracture site after prolapsing into maxillary sinus

Infra orbital nerve involvement - Vb

Question 3

What 2 types of glands are found in the eye lid?

Answer 3

Meibomian glands

Sebaceous glands associated with lash follicles (glands of Zeis)

Question 4

What is the role of meibomian glands?

Answer 4

Prevent evaporation of the tear film and prevent tear spillage

Lipid rich secretion

Question 5

Name 3 conditions fo the eyelid.

Answer 5

Stye
Meibomian cyst
Blepharitis

Question 6

What is the common causative organism in stye?

Answer 6

Staph aureus

Question 7

What is the role of the orbital septum?

Answer 7

Seperation of subcutaneous tissue of eyelid and orbicualris iris muscle from the intra-orbital contents.

Acts as a barrier against superficial infection spreading from the pre-septal to post-septal space (orbital cavity proper)

Question 8

What can obstruction of the drainage system lead to?

Answer 8

Epiphoria

Question 9

What is the vascular tunic made of?

Answer 9

iris
Ciliary body
Choroid

Question 10

What 3 things hold the eye ball in place?

Answer 10

Suspensory ligament
Orbital fat
Extraocular muscles

Question 11

What is presbyopia?

Answer 11

Age related inability to focus near objects

Question 12

Why do eyes converge during accommodation reflex?

Answer 12

Ensure image remains focused on the same point of the retina.

Question 13

Why does focusing on near objects require greater refraction of light?

Answer 13

Because light rays from near-objects are more divergent.

Question 14

What is the most common cause of adult blindness in the UK?

Answer 14

Age-related macular degeneration

Question 15

Where does aqueous humour eventually drain into?

Answer 15

Canal of schlemm (scleral venous channels)

Question 16

What are some signs that can be seen in acute angle-closure glaucoma?

Answer 16

Acutely painful eye 
Irregular oval shaped pupil (fixed) 
Blurring of visions 
Halo around eye due to corneal oedema
N/V

Question 17

Describe IVA FROM.

Answer 17

Inspect
Visual Acuity
Visual Fields

Reflexes
Opthalmoscopy
Movements of the eye