CPOA Ophthalmic Optics 5

Question 1

What is the purpose of a trifocal lens segment compared to a bifocal?

Accepted Answer

It adds an intermediate zone between the distance and near zones

Answer

A trifocal lens has three zones: distance, intermediate, and near, providing clear vision at all three working distances for presbyopic patients.

Question 2

Which neutralization technique uses a lens clock (Geneva lens measure) to determine the approximate prescription of an unknown lens?

Accepted Answer

Lensometry with neutralization

Answer

A lens clock measures the curve on each surface of the lens, and combined with the lens index, the prescription can be approximated through surface power neutralization.

Question 3

A patient's prescription is -3.00 -1.50 x 180. If this is transposed to plus cylinder form, the result is:

Accepted Answer

-4.50 +1.50 x 090

Answer

To transpose: algebraically add sphere and cylinder (-3.00 + (-1.50) = -4.50), change cylinder sign (+1.50), and rotate axis 90° (180° + 90° = 90°).

Question 4

What is the purpose of UV-blocking treatment or material in ophthalmic lenses?

Accepted Answer

To protect the eye from ultraviolet radiation that can cause cataracts and macular damage

Answer

UV-blocking lenses absorb ultraviolet radiation (UVA and UVB) to help protect ocular tissues from cumulative UV damage linked to cataracts and macular degeneration.

Question 5

In ophthalmic optics, what does the term 'meniscus lens' describe?

Accepted Answer

A lens with both surfaces curved in the same direction (concave-convex)

Answer

A meniscus lens has one convex and one concave surface curving in the same direction, which is the standard form used in modern ophthalmic lens design to reduce aberrations.

(CPOA) Certified Paraoptometric Assistant Practice Test

(CPOA) Certified Paraoptometric Assistant Practice Test

CPOA Ophthalmic Optics 5