CPOA Ophthalmic Optics 2

Question 1

A patient's prescription reads +2.50 -1.25 x 090. What type of lens is indicated?

Accepted Answer

Compound hyperopic astigmatic lens

Answer

A plus sphere combined with a minus cylinder indicates a compound hyperopic astigmatic correction.

Question 2

Which term describes the bending of light as it passes from one medium to another of different density?

Accepted Answer

Refraction

Answer

Refraction is the change in direction of light as it crosses the boundary between two media with different indices of refraction.

Question 3

What is the vertex distance, and why does it matter in ophthalmic prescriptions?

Accepted Answer

The distance from the back of the lens to the cornea; affects effective power

Answer

Vertex distance is the distance from the back surface of a lens to the corneal apex, and it affects the effective power delivered to the eye, especially in high prescriptions.

Question 4

A lens with a shorter focal length has which property?

Accepted Answer

Higher power

Answer

Lens power in diopters equals 1 divided by the focal length in meters, so a shorter focal length means greater power.

Question 5

Which type of prism is incorporated into spectacle lenses to treat binocular vision disorders?

Accepted Answer

Base-in or base-out prism

Answer

Base-in or base-out prism is prescribed to help patients with convergence or divergence problems align their eyes properly.

(CPOA) Certified Paraoptometric Assistant Practice Test

(CPOA) Certified Paraoptometric Assistant Practice Test

CPOA Ophthalmic Optics 2