POST TEST FOR MODULE 2: Advanced A-scan Biometry
Catalog
Home
Including:
Section 1: Pseudophakic Scans
Section 2: Immersion Technique
Section 3: IOL Calculations
To
print this test: Go to the "File" menu of the window in
which this appears and click "print".
Instructions: This is an "open-book" test, meaning
you can refer to the module while answering the questions. Use this
printed version for your convenience when referring back to the module
information.
If submitting answers online: Go to the online submission form to enter and submit your answers.
If sending forms in the mail: You must print and send in a copy of the ANSWER SHEET and the EVALUATION FORM to receive credit. Do not mark your answers on this question page and do not send this page in for scoring.
1. A pseudophakic scan measures an eye that:
A. does not have a lens
B. has an IOL in place
C. has a corneal transplant
D. has a dense cataract
E. has a "false" cataract
2. The A-scan instrument uses _____ to calculate the axial length of an eye.
A. a velocity of sound factor
B. a millimeter rule
C. a velocity of light factor
D. a slide rule
E. a centimeter rule
3. Which lens material is the "pseudophakic mode" of most A-scan instruments programmed for?
A. silicone
B. mylar
C. nylon
D. PMMA
E. acrylic
4. Which lens material will cause an error in the axial length measurement if the instrument measures the eye in the "cataract" mode?
A. silicone
B. acrylic
C. PMMA
D. all of the above
E. none of the above
5. Axial length errors due to corneal compression can be totally eliminated only by:
A. monitoring anterior chamber depth
B. adjusting the gain control
C. using the immersion technique
D. changing the printer paper
6. The shell used in the immersion technique can be filled with:
A. air
B. methycellulose
C. saline solution
D. A or C
E. B or C
7. The size of the Hansen shell used in the immersion technique is determined by:
A. the size of the lid opening
B. the corneal diameter
C. the size of the probe
D. the anterior chamber depth
E. the type of filler used
8. The second spike on an immersion A-scan may appear as a closely separated double spike representing:
A. the anterior and posterior lens surfaces
B. the anterior and posterior corneal surfaces
C. the probe tip/cornea interface
D. the probe tip/water interface
9. After a shell is removed, the patient should be given:
A. prednisolone drops
B. dilating drops
C. artificial tears
D. anesthetic drops
10. Regression formulas for IOL calculations are based upon:
A. the patient's old glasses prescriptions
B. theoretical optical formulas
C. post-operative results
D. risk analysis
11. Which formula is a theoretical formula?
A. Holladay
B. Hoffer Q
C. SRK/T
D. all of the above
E. none of the above
12. Which formula is considered to be most accurate for eyes between 22 and 26 mm long?
A. Holladay
B. Hoffer Q
C. SRK/T
D. SRK
E. regression
13. In the IOL formula A-2.5L-.9K, K represents:
A. the flat K reading
B. the average K reading
C. the axial length
D. the IOL constant
E. the desired result in diopters
14. The SRK regression formula would be most accurate in which range? (Hint: look for the zeros in the table in section 3)
A. K= 41.00, AL= 21.00
B. K= 42.00, AL= 22.00
C. K= 44.00, AL= 23.50
D. K= 46.00, AL= 25.00
E. K= 47.00, AL= 29.00
15. In order to produce a post-operative refractive error of -2.00 D, _____ diopters would need to be added to the calculated emmetropic IOL power.
A. -3.00
B. -2.00
C. +1.00
D. +2.00
E. +3.00