ABO NOCE Basic Opticianry Dispensing Instrumentation 2

Question 1

A lensometer measures which of the following properties of an ophthalmic lens?

Accepted Answer

Vertex power, axis, and prism

Answer

The lensometer (focimeter) measures vertex power, cylinder axis, and prismatic power of ophthalmic lenses.

Question 2

When using a manual lensometer to neutralize a single vision lens, which target appearance indicates the lens is properly focused?

Accepted Answer

Clear, stationary lines with the mires centered

Answer

Proper focus on a lensometer is indicated by clear, sharp mire lines that are stationary and centered on the reticle.

Question 3

The pupillary distance (PD) ruler is used primarily to measure which distance?

Accepted Answer

The horizontal distance between the patient's pupil centers

Answer

A PD ruler measures the horizontal distance between the centers of the patient's pupils to ensure optical centers are properly aligned.

Question 4

Which instrument is specifically designed to measure the curvature of a contact lens or the base curve of a spectacle lens?

Accepted Answer

Radiuscope / lens clock

Answer

A radiuscope (for contact lenses) or a lens clock (Geneva gauge) measures the curvature or sagittal depth of lens surfaces.

Question 5

The distometer is used in opticianry to measure which parameter?

Accepted Answer

The vertex distance between the back of the lens and the cornea

Answer

A distometer measures vertex distance, which is the distance from the back surface of the spectacle lens to the apex of the cornea.

ABO NOCE Basic Opticianry Practice Test