Dispensing Instrumentation 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 Dispensing Instrumentation flashcards as text
A lensometer measures which of the following properties of an ophthalmic lens?
Answer: Vertex power, axis, and prism
The lensometer (focimeter) measures vertex power, cylinder axis, and prismatic power of ophthalmic lenses.
When using a manual lensometer to neutralize a single vision lens, which target appearance indicates the lens is properly focused?
Answer: Clear, stationary lines with the mires centered
Proper focus on a lensometer is indicated by clear, sharp mire lines that are stationary and centered on the reticle.
The pupillary distance (PD) ruler is used primarily to measure which distance?
Answer: The horizontal distance between the patient's pupil centers
A PD ruler measures the horizontal distance between the centers of the patient's pupils to ensure optical centers are properly aligned.
Which instrument is specifically designed to measure the curvature of a contact lens or the base curve of a spectacle lens?
Answer: Radiuscope / lens clock
A radiuscope (for contact lenses) or a lens clock (Geneva gauge) measures the curvature or sagittal depth of lens surfaces.
The distometer is used in opticianry to measure which parameter?
Answer: The vertex distance between the back of the lens and the cornea
A distometer measures vertex distance, which is the distance from the back surface of the spectacle lens to the apex of the cornea.
A pupillometer differs from a PD ruler in that it:
Answer: Uses a light reflection from the cornea for more accurate monocular PD measurement
A pupillometer uses corneal light reflexes to more accurately and objectively measure monocular pupillary distances compared to a manual PD ruler.
When using a frame warmer (hot air blower) to adjust a plastic frame, the primary goal is to:
Answer: Soften the acetate to allow adjustment without cracking
A frame warmer heats plastic acetate to make it pliable so the optician can adjust temple angles, pantoscopic tilt, and frame width without cracking the material.