Optical Instrumentation Usage Flashcards
7 cards from real NOCE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Optical Instrumentation Usage flashcards as text
When calibrating a lensometer, a technician uses a standard lens of known power. If the reading differs from the known value, the next step is to:
Answer: Adjust the eyepiece diopter compensation first, then recalibrate
Before calibrating the instrument, the eyepiece must be properly focused for the examiner's eye to eliminate measurement error from accommodation.
An optical coherence tomographer (OCT) used in an optical setting primarily helps the optician by:
Answer: Detecting macular pathology that may affect vision correction outcomes
OCT imaging can detect retinal pathology such as macular degeneration that may explain reduced visual acuity not correctable with spectacles.
A lensometer with an automated printout system marks a dot on the lens. This dot represents the:
Answer: Optical center of the lens
The lensometer marks the optical center (or reference point) of the lens so the optician can verify correct placement relative to the patient's pupil.
Which of the following correctly describes the function of the axis wheel on a manual lensometer?
Answer: It rotates the target to align the cylinder axis of the lens
The axis wheel rotates the lensometer target to align with the cylinder axis of the lens being measured, allowing the cylinder meridians to be properly read.
When measuring a progressive addition lens on a lensometer, the reference point for the distance power should be:
Answer: The prism reference point (fitting cross)
For progressive lenses, distance power is measured at the prism reference point (fitting cross), which is marked by the manufacturer.
A radiuscope is primarily used in contact lens practice to measure:
Answer: The base curve radius of rigid contact lenses
A radiuscope (or optical spherometer) measures the base curve radius of curvature of rigid gas-permeable and hard contact lenses.
In automated lensometry, the instrument determines the cylinder axis by:
Answer: Using a rotating detector array to sense the principal meridians electronically
Automated lensometers use electronic sensors or rotating detector arrays to automatically identify the principal meridians and determine cylinder axis without manual alignment.