AOC AOC Visual Optics and Refraction Concepts

Question 1

Which type of lens is used to correct myopia (nearsightedness)?

Accepted Answer

Minus (concave) lens

Answer

Myopia is corrected with minus (concave) lenses, which diverge light and shift the focal point back onto the retina.

Question 2

The measurement of the refractive error in which the two principal meridians have different powers is called:

Accepted Answer

Astigmatism

Answer

Astigmatism results from an asymmetric cornea or lens where different meridians have different focal points, producing a blurred image.

Question 3

Which instrument measures the curvature of the anterior corneal surface to aid in contact lens fitting and astigmatism assessment?

Accepted Answer

Keratometer

Answer

The keratometer (ophthalmometer) measures the radius of curvature of the central cornea, providing K-readings used in lens fitting and refractive assessment.

Question 4

A patient with +2.50 sphere in each eye most likely has which refractive condition?

Accepted Answer

Hyperopia

Answer

A plus sphere prescription indicates hyperopia (farsightedness), where the eye focuses light behind the retina.

Question 5

The near point of accommodation is defined as:

Accepted Answer

The closest point at which the eye can maintain clear focus

Answer

The near point of accommodation is the closest distance at which the eye can maintain clear focus using maximum accommodative effort.

(AOC) American Orthoptic Council Practice Test

(AOC) American Orthoptic Council Practice Test

AOC AOC Visual Optics and Refraction Concepts