Test 24

1. The following are true about the Jones' test in a patient with epiphora:

a. it is used to detect functional epiphora

b. it should be performed before syringing of the 
    nasolacrimal system

c. a positive Jones I test suggests either hypersecretion or 
    functional epiphora

d. a positive Jones II test suggests partial blockage below 
    the lacrimal sac

e. Jones II test is not necessary if Jones I test is positive
 

Answer
a. T   b.F   c.T   d.T   e.T
Jones tests should be performed in conjunction with 
syringing as it is used to detect functional epiphora. 
If Jones I is positive ie. fluorescence recovered from
the nose without syringing, the patient has either 
hypersecretion or functional epiphora. If negative,
there is an obstruction of the nasolacrimal system 
and Jones II test is carried out by syringing the lacrimal sac.
If fluorescence is recovered with Jones II test, there is 
a physiological or partial anatomical blockage below the sac. If negative, it suggests the presence of a severe functional stenosis and surgery is indicated.
 

2. Nuclear lacrimal scintigraphy:

a. is not useful if the nasolacrimal duct is not patient on 
    syringing

b. uses the same radiotracers as for bone scan

c. uses radioactive iodine as radiotracer

d. required the use of local anaesthesia

e. shows up the canaliculi well
 

Answer
a.T   b.T   c.F   d.F   e.F
Nuclear lacrimal scintigraphy is used to detect functional epiphora. It uses mainly technitium 99m pertechnetate. Local anaesthesia is not required. Canaliculi are not shown.

3. Dacryocystography:

a. involves instilling radio-opaque substance into the 
    conjunctival sac

b. should be avoided in acute dacryocystitis

c. is useful in defining the site of obstruction in a 
    regurgitating mucocele

d. can show up lacrimal sac tumour 

e. if the nasolacrimal duct is non-patent, lacrimal 
    scintigraphy should be performed next

 
Answer
a.F   b.T   c.F   d.T   e.F
Dacryocystography involves the injection of radio-opaque substance into the lacrimal sac. Regurgitating mucocele indicates nasolacrimal duct obstruction and dacryocystography is unlikely to be useful. Lacrimal scintigraphy is useful to detect functional epiphora but not if the nasolacrimal duct is non-patent.

4. The following are true about relative afferent pupillary defect:

a. anisocoria is a feature

b. resolution of the defect can occur if the disease process 
    affects the contralateral eye

c. the defect is seen in lesion of the ciliary ganglion

d. the severity of the defect correlates with visual field 
    defect

e. it can be graded using a density filter
 

Answer
a.F    b.T   c.F   d.T   e.T
Anisocoria is a feature of efferent pupillary defect such as in lesion affecting the ciliary ganglion.

5. The following are features of ptosis caused by myasthenia gravis:

a. a brief eyelid retraction after a saccade from downward 
    gaze to primary position 

b. improvement of ptosis after sleep

c. improvement of ptosis after applying ice to the lid

d. failure of eyelid to descend on downgaze

e. increased ptosis on maintained upgaze

Answer
a.T   b.T  c.T   d.F   e.T
Cogan's twitch test is a feature of myasthenia gravis 
affecting the lid and is characterized by a brief eyelid 
retraction after a saccade from downward gaze to primary position. 
Failure of the eyelid to descend on downgaze is a feature of dystrophic muscle seen in congenital ptosis.

 

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