Test 177  (Ocular anatomy)

1. Edinger-Westphal nucleus: 

a. is a sympathetic nucleus

b. gives off fibres that run with the oculomotor nerve to 
    the orbit

c. receives bilateral nerve fibres from the pretectal nuclei

d. receives fibres from the cerebral cortex that mediates 
    accommodation reflex

e. contains fibres that synapse in the pterygopalatine 
    nucleus
 

Answera.F   b.T  c.T   d.T  e.F
It is an accessory parasympathetic nucleus. It contains fibres that synapse in the ciliary ganglion.

2. The optic canal:

a. lies in the lesser wing of the sphenoid bone

b. connects the anterior cranial cavity with the orbit

c. is lateral to the superior orbital fissure

d. contains ophthalmic artery that lies inferior and medial
    to the optic nerve

e. transmits sympathetic nerves that innervate the eyeball
 

Answera.T  b.F  c.F  d.F  e.T
The optic canal is about 4 to 10 mm long and connects the middle cranial cavity with the orbit. It is situated medial to the superior orbital fissure. The ophthalmic artery that contains the sympathetic plexus lies inferior and lateral to the optic nerve.
 
 

3. The following are normal ageing changes in the cornea:

a. Hassall-Henle bodies

b. Ferry's line

c. decreased transparency of the cornea

d. increased thickness of the Descemet's membrane

e. Hudson-Stähli's line
 

Answer
a.T   b.F  c.T  d.T  e.T
Ferry's line are iron deposit in the cornea found anterior to trabeculectomy bleb.

 

. 4. Deposit found in the Descemet's membrane include:

a. Fleischer's ring

b. Kayser-Fleischer's ring

c. band keratopathy

d. arcus senilis

e. Stocker's line
 

Answer
a.F  b.T  c.F  d.F  e.F
Fleischer's ring is iron deposit within the epithelium found at the base of the cone of keratoconus. 
Kayser-Fleischer's ring contains copper deposit within the Descemet's membrane. 
Band keratopathy is made up of calcium deposit within the Bowman's membrane. 
Arcus senilis contains lipid in the corneal stroma. Stocker's line is epithelial iron deposit at the head of pterygium.

5. On looking to the left, there is an increased contraction of the 
    following muscles:

a. the right inferior oblique 

b. the right medial rectus 

c. the left medial rectus

d. the right superior rectus 

e. the left inferior rectus
 

Answer
a.F   b.T  c.F  d.F  e.F
On looking to the left, there is an increased contraction of the left lateral rectus and right medial rectus and decreased contraction of the left medial rectus and right lateral rectus. The other muscles are not involved in horizontal eye movements.

 

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