CPOA Basic Science 5

Question 1

The choroid is mainly responsible for:

Accepted Answer

Providing blood supply to the outer retina

Answer

The highly vascular choroid supplies oxygen and nutrients to the outer third of the retina, including the photoreceptors.

Question 2

In the context of optics, the unit diopter (D) measures:

Accepted Answer

The refracting power of a lens

Answer

A diopter is the unit of measurement for the refracting power (vergence power) of a lens, defined as 1 divided by the focal length in meters.

Question 3

Which extraocular muscle is responsible for abducting (moving laterally) the eye?

Accepted Answer

Lateral rectus

Answer

The lateral rectus muscle, innervated by CN VI (abducens), is the primary abductor of the eye, moving it away from the nose.

Question 4

The optic chiasm is the structure where:

Accepted Answer

Nasal retinal fibers from each eye cross to the opposite side

Answer

At the optic chiasm, nerve fibers from the nasal half of each retina decussate (cross) to the contralateral optic tract, while temporal fibers remain ipsilateral.

Question 5

The lens of the eye grows throughout a person's lifetime, adding layers like an onion. This growth contributes to which age-related condition?

Accepted Answer

Presbyopia

Answer

As the lens grows and becomes denser and less flexible with age, its ability to change shape for near focus (accommodation) decreases, resulting in presbyopia.

(CPOA) Certified Paraoptometric Assistant Practice Test

(CPOA) Certified Paraoptometric Assistant Practice Test

CPOA Basic Science 5