Board Certified Ophthalmologist FREE Board Certified Ophthalmologist Optics and Refraction Principles Questions and Answers 2

Question 1

A patient with a keratometry reading of 44.00 D in one meridian and 46.00 D in the perpendicular meridian has what type and amount of corneal astigmatism?

Accepted Answer

2.00 D with-the-rule astigmatism

Answer

2.00 D against-the-rule astigmatism

Answer

2.00 D oblique astigmatism

Answer

4.00 D irregular astigmatism

Question 2

What is the critical angle for total internal reflection at a crown glass-air interface if the refractive index of crown glass is 1.52?

Accepted Answer

41.1 degrees

Answer

48.8 degrees

Answer

33.3 degrees

Answer

56.4 degrees

Question 3

A patient wearing a +10.00 D aphakic spectacle correction at a vertex distance of 12 mm requires what equivalent contact lens power?

Accepted Answer

+11.40 D

Answer

+10.00 D

Answer

+8.93 D

Answer

+12.50 D

Question 4

In Gullstrand's schematic eye, what is the approximate total refractive power of the eye?

Accepted Answer

+58.6 D

Answer

+43.0 D

Answer

+63.0 D

Answer

+20.0 D

Question 5

Which aberration causes a point source of light to appear as a comet-shaped blur when imaged through the peripheral portion of a spherical lens?

Accepted Answer

Coma

Answer

Spherical aberration

Answer

Chromatic aberration

Answer

Distortion

Question 6

A prism with an apical angle of 10 degrees and refractive index of 1.5 produces approximately how many prism diopters of deviation?

Accepted Answer

5 prism diopters

Answer

10 prism diopters

Answer

15 prism diopters

Answer

7.5 prism diopters