ROUB Study Guide UPDATED Exam Questions and CORRECT Answers
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ROUB
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ROUB
ROUB Study Guide UPDATED Exam
Questions and CORRECT Answers
If your biometry instrument has one pseudophakic eye-type setting, what is the only IOL
material that can accurately be measured? - CORRECT ANSWER- Polymethyl
methacrylate (PMMA)
If a gain setting is increased in order to obtain a ...
ROUB Study Guide UPDATED Exam
Questions and CORRECT Answers
If your biometry instrument has one pseudophakic eye-type setting, what is the only IOL
material that can accurately be measured? - CORRECT ANSWER-✔✔ Polymethyl
methacrylate (PMMA)
If a gain setting is increased in order to obtain a 100% tall retina and sclera echo, what type of
cataract is being evaluated? - CORRECT ANSWER-✔✔ A dense cataract
What transducer frequency is generally used for a biometry A-scan probe? - CORRECT
ANSWER-✔✔ 10 MHz
What is the velocity of a biometer that only uses an average velocity to measure the entire
axial length? - CORRECT ANSWER-✔✔ 1550 m/sec
What is one of the most important features of a biometer? - CORRECT ANSWER-✔✔
Display screen
What are the velocity settings for a phakic eye? - CORRECT ANSWER-✔✔ 1532 m/sec for
the aqueous; 1641 m/sec for the lens; and, 1532 m/sec for the vitreous cavity
What should the examiner do to reduce the presence of a reverberation echo created by a
dense cataract? - CORRECT ANSWER-✔✔ Reduce the gain
What is the term for the electronic calipers that measure the distance between two or more
anatomic interfaces? - CORRECT ANSWER-✔✔ Gates
Of the following settings on the biometer (gain, gates, A-scan probe frequency, eye type, and
screen brightness), which cannot be changed by the examiner? - CORRECT ANSWER-✔✔
A-scan probe frequency
What is the proper sound velocity used to measure the distance between the anterior and
posterior lens interfaces in a phakic eye? - CORRECT ANSWER-✔✔ 1641 m/sec
,When performing immersion biometry, which gate in relation to the initial spike represents
the cornea? - CORRECT ANSWER-✔✔ Corneal gate is to the right of the initial spike
What is the possible cause for a biometry instrument to indicate an unusually short
measurement of a pseudophakic eye with a PMMA implant? - CORRECT ANSWER-✔✔
Multiple signal of the echo with improper identification of the retina
What biometer setting changes the degree of echo amplification? - CORRECT ANSWER-
✔✔ Gain
What is the term for the relative strength or amplitude of an echo displayed on a biometer? -
CORRECT ANSWER-✔✔ Reflectivity
When measuring an eye that has no crystalline lens, the instrument should be set on which
eye type? - CORRECT ANSWER-✔✔ Aphakic
What is the term for the "markers" or "cursors" displayed on the screen of a biometry
instrument that provide electronic measurements of distance between two or more acoustic
interfaces? - CORRECT ANSWER-✔✔ Gates
What is the term for the capacity of an ultrasound instrument to display two or more
interfaces that are very anatomically close to one another as separate echoes? - CORRECT
ANSWER-✔✔ Resolution
How does increasing the gain setting on the biometer affect the display echo? - CORRECT
ANSWER-✔✔ It increases the amount of amplification of the echo
What is the range of ophthalmic biometry frequencies? - CORRECT ANSWER-✔✔ 8-12
MHz
How is the resolution affected when the gain is set at maximum? - CORRECT ANSWER-
✔✔ The resolution is less
, A non-focused sound beam is always utilized by which type of scan? - CORRECT
ANSWER-✔✔ Diagnostic A-scan
What scan is used to obtain a two-dimensional image of the globe? - CORRECT ANSWER-
✔✔ Diagnostic B-scan
What is the term for a one-dimensional amplitude scan? - CORRECT ANSWER-✔✔ A-scan
The strength of an echo is dependent on what three factors? - CORRECT ANSWER-✔✔
Gain, difference in density, and proper alignment
What type of scan uses Prager or scleral shells? - CORRECT ANSWER-✔✔ Immersion A-
scan
How often should the filter of a biometry instrument be vacuumed? - CORRECT ANSWER-
✔✔ Once a month
Measurement of axial length of the eye, thickness of an extraocular muscle, and tumor height
are all within the definition of what term? - CORRECT ANSWER-✔✔ Biometry
What is the leading cause of an unplanned, post-operative refractive error? - CORRECT
ANSWER-✔✔ An error in the measurement of axial length
An error of 0.1 mm in the axial length measurement can result in a post-operative refraction
error of how many diopters? - CORRECT ANSWER-✔✔ 0.25D
If multiple axial length readings are taken from a single eye, each measurement should be
within how many millimeters? - CORRECT ANSWER-✔✔ 0.2 mm
The difference in axial length between two eyes should measure within how many
millimeters? - CORRECT ANSWER-✔✔ 0.3 mm
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