18 Questions
Which technique uses a 780 nm infrared light wave for ocular measurements?
Partial coherence interferometry
Which type of biometry technique requires contact with the cornea?
Applanation
Which technique is more precise than a 10 MHz sound wave for ocular measurements?
Partial coherence interferometry
Which factor impacts the height of the A-Scan spikes in biometry?
Angle of incidence
Which instrument setting is impacted by the shape and smoothness of the interface in biometry?
Interface
Which technique is less useful in cases of very dense cataract and corneal edema due to light absorption or eye fixation?
IOL Master
What is the purpose of adjusting the Sound Velocity in an ultrasound examination?
To calculate accurate axial eye length measurements
Which measurement mode would be most suitable for a patient with an artificial lens implanted (IOL)?
Pseudophakic
What does Gain control in ultrasonic devices primarily affect?
The visualization of weaker signals
Why is adjusting the instrument's Gain setting important in ultrasonography?
To amplify returning ultrasonic signals uniformly
Which parameter should be checked before beginning an examination to ensure accurate measurements?
Sound Velocity
Which of the following modes provides choices for manual or automatic measuring approaches?
Phakic
How does the angle of incidence impact the height of A-Scan spikes?
Parallel incidence results in high-amplitude spikes, while oblique incidence compromises spike height.
What factor influences the height of A-Scan spikes by reflecting away part of the returning echo from the probe tip?
The shape and smoothness of the interface
Which statement best describes how absorption impacts A-Scan spikes?
Greater absorption occurs in denser structures, leading to weaker echoes.
How does the shape and smoothness of the interface affect A-Scan spikes?
Irregularities in the interface decrease the strength of returning echoes.
Which factor directly determines how much of the returning echo is received by the probe tip?
Angle of incidence
How does the density of a structure impact sound beam absorption?
Greater density leads to increased sound beam absorption.
Learn about the instrument settings that need to be adjusted before starting an ultrasound examination, including sound velocity, measurement mode, gain, and position of gates or cursors. This quiz also explains why retinal spike quality is reduced in the case of an extremely dense cataract.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
