Chapter 3-contact Lenses

Question 1

Rigid contact lenses are often removed by blinking them out. For this technique to work:
a) the lens should be moved onto the sclera first
b) the lens must be centered on the eye
c) the patient must flip the edge of the lens with the finger
d) the patient must squint and look up

Answer 1

B- the lens must be centered on the eye

Question 2

Which of the following regarding “topping off” cleaning/disinfecting solutions is false? (“Topping off” refers to the practice of adding a little fresh solution to what was left in the case from the last cleaning.)
a) it weakens the lens material
b) it contaminates the solution
c) it dilutes the solution
d) disinfection is compromised

Answer 2

A- it weakens the lens material

Question 3

Corneal edema is caused by:
a) excess oxygen permeability
b) insufficient oxygen
c) excess carbon monoxide
d) excess tear production

Answer 3

B- insufficient oxygen

Question 4

Giant papillary conjunctivitis is suspected to be:
a) an allergic response
b) an infection
c) a response to mechanical irritation d) a sign of overwear

Answer 4

A- an allergic response

Question 5

The advantages of soft lenses include all of the following except:
a) they are more comfortable than rigid lenses
b) they provide crisper vision than rigid lenses
c) there is less lens displacement
d) there is less lens loss

Answer 5

B- they provide crisper vision than rigid lenses

Question 6

One of the main disadvantages of soft lenses is:
a) frequent lens loss
b) poor durability
c) low oxygen permeability
d) corneal injury on insertion

Answer 6

B- poor durability

Question 7

Which of the following probably would be a poor candidate for the monovision technique?
a) a public speaker
b) a teacher
c) a bookkeeper
d) an actor

Answer 7

C- a bookkeeper

Question 8

Selecting the power of a spherical soft contact lens is based on:
a) the spherical element found on refractometry
b) the cylindrical element found on refractometry
c) the spherical equivalent of the refractometric measurement
d) the refractometric and keratometric measurements

Answer 8

C- the spherical equivalent of the refractometric measurement

Question 9

The most common source of residual astigmatism in contact lens wearers is: a) the tear lens
b) the cornea
c) the crystalline lens
d) the retina

Answer 9

C- the crystalline lens

Question 10

The fact that gas-permeable contact lens material allows more oxygen to the eye means that:
a) the lens can be larger than a PMMA lens
b) the lens is more comfortable than a PMMA lens
c) lens movement is not an important factor
d) the lens can be allowed to rest on the lower lid margin

Answer 10

A- the lens can be larger than a PMMA lens

Question 11

All of the following are suitable bandage contact lenses except:
a) a collagen disintegrating lens
b) a disposable soft lens
c) a low water content lens
d) a thin soft lens

Answer 11

C- a low water content lens