Optical Instrumentation Use Questions and Answers Flashcards
7 cards from real ABO NOCE Basic Opticianry 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 Use Questions and Answers flashcards as text
When using a pupillometer to measure monocular PDs, what is the correct patient fixation target?
Answer: The instrument's internal fixation light for each eye separately
The patient fixates on the internal fixation light while each eye is measured separately to obtain accurate monocular PDs.
Which of the following best describes the function of a frame warmer (frame heater)?
Answer: It softens plastic frames for adjustment without cracking
A frame warmer uses heat (salt pan, hot air, or infrared) to soften plastic acetate frames so they can be safely adjusted without cracking.
An auto-lensometer differs from a manual lensometer primarily in that it:
Answer: Automatically determines sphere, cylinder, axis, and prism without manual wheel adjustments
An auto-lensometer (focimeter) electronically measures and displays all lens parameters automatically when the lens is placed on the lens stop.
When verifying lenses with a lensometer, the cylinder power of a –2.00 –1.50 × 090 lens is measured by:
Answer: Noting the difference between the two drum readings when each set of lines clears
Cylinder power equals the algebraic difference between the two drum readings (first meridian minus second meridian) when each set of lines sharpens.
A keratometer (ophthalmometer) is used to measure:
Answer: The curvature of the anterior corneal surface
The keratometer measures the radius of curvature of the anterior corneal surface, typically used for contact lens fitting.
When using an ultrasonic cleaner for eyewear, frames with which type of lens treatment should be cleaned with caution or avoided?
Answer: Anti-reflective (AR) coated lenses
Ultrasonic cleaners can delaminate or damage anti-reflective coatings, so manufacturer guidelines should be followed for AR-coated lenses.
On a lensometer, the axis scale reads in degrees from 0 to 180. When the axis drum shows 045, the cylinder axis is:
Answer: 45 degrees from horizontal
An axis of 045 means the cylinder axis is oriented 45 degrees measured from the 0-degree (horizontal) meridian using the standard ANSI notation.