ABO NOCE Basic Opticianry Optical Instrumentation Use 5

Question 1

When using a digital PD ruler to measure near PD, the standard working distance used is:

Accepted Answer

40 cm (16 inches)

Answer

The standard near working distance used when measuring near PD is 40 cm (approximately 16 inches), which corresponds to 2.50 D of accommodation demand.

Question 2

An auto-lensometer (auto-focimeter) differs from a manual lensometer primarily because it:

Accepted Answer

Automatically calculates and displays sphere, cylinder, axis, and prism without manual focusing

Answer

An auto-lensometer electronically detects and displays all lens parameters (sphere, cylinder, axis, prism) automatically without manual focusing steps.

Question 3

A lensometer drum is turned from +2.00 D to -1.50 D while focusing the cylinder lines of a lens. The cylinder power of this lens is:

Accepted Answer

-3.50 D

Answer

Cylinder power equals the second (cylinder meridian) reading minus the first (sphere meridian) reading: -1.50 - (+2.00) = -3.50 D.

Question 4

During contact lens fitting, the slit lamp biomicroscope is used to:

Accepted Answer

Assess contact lens fit and corneal health under magnification

Answer

The slit lamp provides magnified, illuminated views of the contact lens position and the anterior eye structures to assess fit and corneal integrity.

Question 5

If the lensometer target shows both sets of lines (sphere and cylinder) crossing at the same drum reading, the lens is:

Accepted Answer

A spherical lens (no cylinder)

Answer

When all target lines focus at the same power reading, there is no power difference between meridians, indicating a purely spherical lens.

ABO NOCE Basic Opticianry Practice Test

ABO NOCE Basic Opticianry Practice Test

ABO NOCE Basic Opticianry Optical Instrumentation Use 5