Practice Test 1
1. Which is the most important benefit for contact lens wear?
a. wide field of view
b. eye color enhancement
c. more natural appearance
d. convenience
2. The person responsible for inventing the soft contact lens is
a. Leonardo da Vinci
b. Kevin Tuohy
c. Otto Wichterle
d. F.A. Muller
3. The major drawback to PMMA contact lenses is:
a. long adfaptation time
b. decreased comfort
c. poor optical quality
d. lack of oxygen transmission
4. A disadvantage of rigis gas permeable (RGP) lenses is:
a. crisp optics
b. less comfort than soft lenses
c. can polish and modify
d. correct most astigmatism
5. Which type of contact lens offers the best comfort and easiest adaptation?
a. PMMA
b. rigid gas peameable (RGP)
c. Silicone
d. Soft (hydrophilic)
6. The first rigid gas permeable contact lens material was
a. PMMA
b. HEMA
c. CAB
d. Polycon
7. The major drawback of contact lens materials containing silicone is:
a. optics
b. wettability
c. durability
d. oxygen transmission
8. A material's ability to keep its shape when subjected to stress is called:
a. modulus of elasticity
b. hardness
c. stiffness
d. tensile strength
9. Materials that carry an overall electric charge are said to be:
a. inert
b. nonionic
c. ionic
d. hydrophilic
10. Which is a characteristic of ionic contact lens materials?
a. neutral electric charge
b. deposit prone
c. inert
d. fewer checmical interactions
11. Which contact lens material in the following list is not based on HEMA?
a. tefilcon
b. vifilcon
c. polymacon
d. atlafilcon
12. The major source of oxugen to the cornea during sleep is from the
a. atmosphere
b. palpebral conjunctiva
c. limbal vessels
d. contact lens
13. The partial pressure of oxygen in the atmosphere is
a. 760 mmHg
b. 78 mmHg
c. 155 mmHg
d. 21 mmHg
14. The rate at which oxygen passes through a specific contact lens of a given thickness is the
a. oxygen transmissibility
b. oxygen permeability
c. solubilituy coefficient
d. diffusion coefficient
15. Calculate the Dk/L of the following lens: DK = 16 x 10 -11, L = 0.05mm
a. 80 x 10-9
b. 32 x 10-9
c. 32 x 10-11
d. 16 x 10-9
16. Which of the following methods for calculating oxygen transmissibility would give the lowest value for a +3.00D lens?
a. original Fatt method (Dk), center thickness (L)
b. coulometric technique (Dk), center thickness (L)
c. modified Fatt method (DK), average thickness (L)
d. original Fatt method (Dk), average thickness (L)
17. An example of an in-vivo technique of measuring oxygen transmission is
a. EOP
b. modified Fatt
c. cuolometric
d. oxygen flux
18. A major adverse effect of lack of oxygen (hypoxia) to the cornea is
a. decreased comfort
b. blurred vision
c. corneal dessication
d. corneal edema
19. The method of measuring oxygen permeability that is the most accurate is the
a. original Fatt method
b. modified Fatt
c. coulometric method
d. EOP
20. The method of oxygen permeability measurement historically used by contact lens manufacturers is
a. original Fatt method
b. modified Fatt
c. cuolometric method
d. EOP
21. A contact lens iwth an EOP of 7% allows how much available atmospheric oxygen to the cornea?
a. 7%
b. 21%
c. 33%
d. 50%
22. A hydrogel contact lens with a water content of 64% and no ionic charge would fall into which FDA Cllassification group?
a. Group 1
b. Group 2
c. Group 3
d. Group 4
23. Which contact lens manufacturing method is the most useful for low volume production and custom parameters?
a. spin casting
b. lathe cutting
c. cast molding
24. The lack of undue adverse ocular effects with normal use of a contact lens is called
a. safety
b. efficacy
c. performance standards
d. biocompatibility
25. Which is not a part of typical preclinical testing during the regulatory process?
a. chemistry
b. microbiology
c. clinical trials
d. toxicology