ABO NOCE Basic Opticianry Ophthalmic Optics and Principles Questions and Answers 4

Question 1

Which type of lens aberration causes the image of a point source off the optical axis to appear as a comet-shaped blur?

Accepted Answer

Coma

Answer

Coma produces a comet-shaped blur for off-axis point sources because rays through different zones of the lens converge to different points.

Question 2

The Abbe number (V-number) of a lens material is used to measure which optical property?

Accepted Answer

Chromatic dispersion

Answer

The Abbe number indicates the degree of chromatic dispersion; a higher Abbe number means less chromatic aberration.

Question 3

A patient has 2Δ base-in prism OD and 2Δ base-in prism OS. What is the total prism effect?

Accepted Answer

4Δ base-in

Answer

Base-in prisms in both eyes add together for horizontal vergence demand, totaling 4Δ base-in.

Question 4

What is the purpose of a lenticular lens design in high-power prescriptions?

Accepted Answer

To reduce lens weight and thickness by limiting the optical zone

Answer

Lenticular designs place full prescription power only in a central optical zone, reducing overall lens weight and thickness for high-power corrections.

Question 5

Which formula correctly describes Snell's Law of refraction?

Accepted Answer

n₁ × sin θ₁ = n₂ × sin θ₂

Answer

Snell's Law states n₁ sin θ₁ = n₂ sin θ₂, relating the indices of refraction and angles at a refracting interface.

ABO NOCE Basic Opticianry Practice Test

ABO NOCE Basic Opticianry Practice Test

ABO NOCE Basic Opticianry Ophthalmic Optics and Principles Questions and Answers 4