FREE ABO Optics and Refraction Principles Questions and Answers

Question 1

A patient with a prescription of +6.00 D sphere is refracted at a vertex distance of 15 mm.
If the patient's new glasses are fit with a vertex distance of 10 mm, what is the compensated lens power required to provide the same effective power at the new distance?

Accepted Answer

+6.19 D

Answer

+5.82 D

Answer

+6.00 D

Answer

+5.50 D

Question 2

A patient looks 5 mm below the optical center of a lens with a power of -4.00 D in the vertical meridian. According to Prentice's Rule, what is the amount and direction of the induced prism?

Accepted Answer

2.0Δ Base Up

Answer

4.0Δ Base Down

Answer

2.0Δ Base Down

Answer

4.0Δ Base Up

Question 3

Which of the following optical principles correctly describes the correction for hyperopia?

Accepted Answer

A converging (convex) lens is used to move the focal point forward onto the retina.

Answer

A diverging (concave) lens is used to move the focal point backward onto the retina.

Answer

A cylindrical lens is used to correct the two different focal points.

Answer

A prism is used to realign the image onto the fovea.

Question 4

During subjective refraction to refine astigmatism, a Jackson Cross Cylinder (JCC) is used. What is the primary function of this instrument?

Accepted Answer

To refine the cylinder axis and power.

Answer

To determine the spherical equivalent of the prescription.

Answer

To measure the intraocular pressure.

Answer

To assess the patient's binocular balance.

Question 5

According to Snell's Law, when a ray of light passes from a medium of lower refractive index (like air) to a medium of higher refractive index (like the cornea) at an oblique angle, the ray of light will:

Accepted Answer

Bend toward the normal.

Answer

Bend away from the normal.

Answer

Be completely reflected.

Answer

Continue in a straight line without deviation.

Question 6

A patient's prescription is -2.00 -1.00 x 180. What is the total power of this lens in the 90-degree meridian?

Accepted Answer

-3.00 D

Answer

-2.00 D

Answer

-1.00 D

Answer

-2.50 D

A patient with a prescription of +6.00 D sphere is refracted at a vertex distance of 15 mm.If the patient's new glasses are fit with a vertex distance of 10 mm, what is the compensated lens power required to provide the same effective power at the new distance?

A patient with a prescription of +6.00 D sphere is refracted at a vertex distance of 15 mm.
If the patient's new glasses are fit with a vertex distance of 10 mm, what is the compensated lens power required to provide the same effective power at the new distance?