Test 4
1. Regarding accommodation:
a. half of the amplitude should always remain in reserve to avoid fatigue 

b. the accommodative amplitude decreases by about 1.5D every 4 
    years between the age of 40 and 48 

c. accommodation decreases with age because the zonules become 
    less elastic 

d. movement of the cornea occurs during accommodation 

e. accommodation can not occur in the absence of convergence


2. Stenopaeic slit:

a. is used to determine the power of the sphere 

b. can determine the best vision in a certain axis 

c. can help determine the position of an iridotomy in corneal 

d. can affect the visual acuity by the width due to the effect of 

e. in a patient with astigmatism can improve the vision

3. The following are true about Hertel's exophthalmometer:

a. the measurement may be affected by the presence of strabismus 

b. the foot plate should rest on the lateral canthus rather than the 
    orbital for accurate reading 

c. patients of African origin has a higher normal reading than European 

d. a difference in readings between the two eyes of up to 5 mm is 
    normal in up to 50% of the population 

e. can be used to monitor the progress of Grave's eye disease


4. The astronomical telecsope:

a. has an eye piece which has minus power 

b. the separation of the eye piece and the objective piece is the sum 
    of the focal lengths 

c. the secondary focal point of the objective lens falls at the primary 
    focal point of the eyepiece 

d. the image is erect 

e. the emergent rays are parallel


5. Myopic shift occurs in:

a. keratoconus 

b. spasm of the ciliary body 

c. staphyloma 

d. lens subluxation 

e. brittle diabetes

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