Optics & Lens Design Flashcards
6 cards from real ABO practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Optics & Lens Design flashcards as text
Progressive addition lenses (PALs) differ from bifocals primarily because they:
Answer: Offer a gradual power change from distance to near
PALs provide a continuous, gradual power progression eliminating the visible segment line of bifocals.
Add power in a bifocal lens is defined as:
Answer: Near power minus distance power
Add power equals the near prescription power minus the distance prescription power and is always a positive value.
Lenticular lens design is most commonly used when:
Answer: Very high plus powers are needed
Lenticular design places full correction only in a central optical zone, reducing weight and thickness for very high plus prescriptions.
Aspheric lens surfaces are used primarily to:
Answer: Reduce peripheral aberrations and allow a flatter lens profile
Aspheric surfaces vary in curvature across the lens to minimize spherical and peripheral aberrations while enabling a thinner, flatter design.
In a toric lens, the two principal meridians are oriented:
Answer: Perpendicular to each other
A toric lens has two principal meridians at 90° to each other, each with a different curvature and power, correcting astigmatism.
Polycarbonate lenses are the preferred material for safety eyewear primarily because of their:
Answer: Superior impact resistance
Polycarbonate's exceptional impact resistance makes it the material of choice for safety, sports, and children's eyewear.