ABO NOCE Basic Opticianry Optical Instrumentation Use Questions and Answers 2

Question 1

When using a lensometer (lensmeter) to neutralize a lens, the mires are brought into sharp focus. For a spherocylindrical lens, in what order are the power meridians found?

Accepted Answer

The first clear focus gives the sphere power; the second clear focus gives the sphere + cylinder power

Answer

The first clear focus gives the cylinder power; the second gives the sphere

Answer

Both meridians focus simultaneously at the sphere power

Answer

The cylinder is read first when the mires are rotated to 90°

Question 2

The keratometer (ophthalmometer) measures which property of the cornea?

Accepted Answer

The curvature (radius of curvature) of the central anterior corneal surface

Answer

The thickness of the cornea

Answer

The intraocular pressure

Answer

The axial length of the eye

Question 3

When verifying a finished lens with a lensometer, the optical center is found when:

Accepted Answer

The mire target is centered in the reticle with no prism displacement

Answer

The drum reading equals zero diopters

Answer

The mire target is blurred and displaced vertically

Answer

The axis wheel is set to 180°

Question 4

What does a pupilometer measure, and what advantage does it have over a PD ruler?

Accepted Answer

It measures pupillary distance; it provides more accurate monocular PD measurements with less parallax error

Answer

It measures pupil diameter; it gives more accurate refraction results

Answer

It measures the vertex distance; it eliminates the need for a ruler

Answer

It measures near PD; it automatically compensates for convergence

Question 5

The Geneva lens gauge (lens clock) measures:

Accepted Answer

The surface power (base curve) of a lens surface

Answer

The total lens power in diopters

Answer

The lens thickness at the center

Answer

The frame PD

Question 6

Which ANSI Z80.1 tolerance applies to the sphere power of a single vision lens with a prescribed power of -4.50 D?

Accepted Answer

±0.13 D

Answer

±0.12 D

Answer

±0.25 D

Answer

±0.18 D

When using a lensometer (lensmeter) to neutralize a lens, the mires are brought into sharp focus.For a spherocylindrical lens, in what order are the power meridians found?

When using a lensometer (lensmeter) to neutralize a lens, the mires are brought into sharp focus.
For a spherocylindrical lens, in what order are the power meridians found?