FREE Board Certified Ophthalmologist Optics and Refraction Principles Questions and Answers Flashcards
6 cards from real Board Certified Ophthalmologist practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 FREE Board Certified Ophthalmologist Optics and Refraction Principles Questions and Answers flashcards as text
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?
Answer: 2.00 D with-the-rule astigmatism
The 2.00 D difference between meridians with the steeper curvature at 90 degrees indicates with-the-rule astigmatism.
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?
Answer: 41.1 degrees
The critical angle is calculated as arcsin(1/1.52), which equals approximately 41.1 degrees.
A patient wearing a +10.00 D aphakic spectacle correction at a vertex distance of 12 mm requires what equivalent contact lens power?
Answer: +11.40 D
Using the vertex distance formula, moving a plus lens closer to the eye requires increasing its power, yielding approximately +11.40 D.
In Gullstrand's schematic eye, what is the approximate total refractive power of the eye?
Answer: +58.6 D
Gullstrand's schematic eye has a total refractive power of approximately +58.6 diopters combining corneal and lenticular contributions.
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?
Answer: Coma
Coma produces an asymmetric, comet-shaped blur pattern for off-axis point sources passing through different lens zones.
A prism with an apical angle of 10 degrees and refractive index of 1.5 produces approximately how many prism diopters of deviation?
Answer: 5 prism diopters
Using the thin prism approximation, deviation = (n-1) × apical angle = (1.5-1) × 10 = 5 prism diopters.