COA Flashcards - Spectacle Skills 3% of exam

Question 0

Explain how to transpose a spherocylinder lens from plus to minus cylinder form, or from minus to plus cylinder?

Answer 0

Algebraically add the sphere and cylinder powers, retain the cylinder power but change the cylinder sign, and change the cylinder axis by 90 degrees. Transpose +2.00 -2.50 x 90 ==> -.50 + 2.50 x 180

Question 1

Which instrument measures the radius of curvature, or base curve, of a spectacle lens surface in diopters?

Answer 1

Geneva lens clock or measure

Question 2

What is the spherical equivalent of -2.00 +3.00 x 90?

Answer 2

-0.50 sphere

Question 3

The trifocal portion of a +2.00 reading add will be _____.

Answer 3

+1.00

Question 4

In the terms of lens thickness, the greater the refractive index, the _____ the lens.

Answer 4

Thinner

Question 5

The distance from the center of the pupil of one eye to the center of the pupil of the other eye is termed _____?

Answer 5

Interpupillary Distance

Question 6

What is measured to obtain a monocular measurement of the IPD (interpupillary distance)?

Answer 6

The distance from the bridge of the nose to the center of a pupil.