Test 31   (glaucoma)

 

Refer to question 1

1. The above picture is taken from a patient in his mid-20s. 
   The following are true:

a. the iris is likely to be convex

b. there is posterior insertion of the iris root

c. lattice degeneration is common

d. the sex distribution of this condition is the same

e. the risk of glaucoma development is commoner in 
    females than males
 

Answer

a.F   b.T   c.T   d.T   e.F
The picture shows pigment dispersion syndrome.
The iris is concave. Although the sex distribution is the same, the risk of glaucoma is commoner in males than females (3:1).

 
 

Refer to question 2

2. The above is an appearance obtained through gonioscopy:
 

a. the angle is at risk of closure

b. there may be peripupillary transillumination

c. the patient may be pseudophakic

d. the pressure is likely to be above 21mmHg

e. the patient may be a poorly controlled diabetic
 

Answer
a. F   b.T   c.T   d.F   e.T
The trabecular meshwork is fully open but heavily pigmented. This is seen in pigment dispersion syndrome, pseudoexfoliation syndrome (with peripupillary transillumination), following a difficult surgery in which there is iris trauma or poorly controlled diabetic in which there is shedding of the pigment from the pigmented layer of posterior iris. The pressure may be normal in all these cases. 

 
 

Refer to question 3

3. The following are true with regard to the picture above:

a. the patient may be of tall stature and myopic 

b. deafness may be present

c. there may be arachnodactyly

d. there is a risk of lens dislocation

e. if the pressure is raised, the treatment of choice is 
   intensive pilocarpine

 
Answer
a.F   b.T   c.F   d.T   e.F
The dilated pupil shows the entire lens and supporting zonules to be within the pupillary space. The patient is at risk of pupillary block glaucoma. The treatment of choice is to lay the patient supine and use mydriatic.

Microspherophakia is associated with Weill-Marchesani syndrome, in which the lens is displaced superior temporally. Other features of this syndrome include small stature, brachydactyly, deafness, and a high degree of myopia
.
 
 
 

Question 4

4. Regarding the above picture: 

a. it is obtained with OCT (optical coherence 
    topography)

b. it is obtained with the use of laser

c. it is used to analyse nerve fibre layer thickness

d. the blue area has more nerve fibres than the red area

e. it can be used to diagnose glaucoma on its own

Answer
a.F   b.T   c.T   d.F   e.F
The above picture is laser scanning polarimetry.
It analyses nerve fibre layer thickness. The blue 
area has less nerve fibres than the red area (see the chart on the picture)..
 
 

Refer to question 5

5. With regard to the above visual field results:

a. it is obtained with octopus perimeter

b. the test uses yellow light

c. the M cells are tested 

d. it tests neurones that are sensitive to low-contrast 
    stimulus

e. it can theoretically detect glaucoma at an early stage
 

Answer
a.F   b.F   c.T   d.T   e.T
The visual field is obtained with frequency doubling perimetry. It test the non-linear M neurones which are believed to die early in glaucoma. The M neurones respond to low-contrast, high temporal frequency stimulus..

 

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