ABO NOCE Basic Opticianry Ophthalmic Optics and Principles Questions and Answers 5

Question 1

What is the dioptric power of a plano-convex lens with a front surface radius of curvature of 100 mm in air (n=1.00, n'=1.50)?

Accepted Answer

+5.00 D

Answer

Surface power = (n' − n) / r = (1.50 − 1.00) / 0.10 m = 0.50 / 0.10 = +5.00 D.

Question 2

Which term describes the ability of a lens material to polarize light at a specific angle, known as Brewster's angle?

Accepted Answer

Polarization by reflection

Answer

At Brewster's angle, reflected light becomes completely polarized parallel to the surface, which is the basis for polarized ophthalmic lenses reducing glare.

Question 3

When transposing −1.50 +2.00 × 090 into minus cylinder form, the result is:

Accepted Answer

+0.50 −2.00 × 180

Answer

Add sphere + cylinder = −1.50 + 2.00 = +0.50; reverse cylinder sign = −2.00; rotate axis 90° → 180°: result is +0.50 −2.00 × 180.

Question 4

A prism of 5Δ is prescribed base-up OD. In which direction does the image appear displaced to that eye?

Accepted Answer

Upward

Answer

A base-up prism refracts light downward through the prism, making the image appear displaced upward (toward the apex).

Question 5

What is the minimum vertex distance that must be accounted for when converting a spectacle prescription to contact lens power, according to standard practice?

Accepted Answer

Any prescription over ±4.00 D

Answer

By standard ophthalmic convention, vertex distance compensation is required when spectacle powers exceed ±4.00 D.

ABO NOCE Basic Opticianry Practice Test

ABO NOCE Basic Opticianry Practice Test

ABO NOCE Basic Opticianry Ophthalmic Optics and Principles Questions and Answers 5