ABO Ophthalmic Dispensing

Question 1

What is the minimum thickness requirement for safety lenses meeting ANSI Z87.1 standards?

Accepted Answer

2.0 mm for glass lenses

Answer

ANSI Z87.1 safety standards require dress safety glass lenses to have a minimum thickness of 2.0 mm. Polycarbonate and trivex have different requirements due to their impact resistance.

Question 2

Which lens material has the highest index of refraction among common ophthalmic materials?

Accepted Answer

High-index 1.74 plastic

Answer

High-index 1.74 plastic has the highest index of refraction commonly available, allowing the thinnest possible lens for high prescriptions.

Question 3

What measurement determines the vertical position of a progressive lens on the patient's face?

Accepted Answer

Fitting height

Answer

The fitting height measures from the bottom of the lens to the center of the pupil, crucial for proper placement of the progressive corridor.

Question 4

Which frame measurement represents the longest horizontal dimension of the lens opening?

Accepted Answer

Eye size (A dimension)

Answer

The eye size or A dimension represents the longest horizontal measurement of the lens shape in a frame, measured in millimeters.

Question 5

What is the primary advantage of polycarbonate lenses over CR-39?

Accepted Answer

Superior impact resistance

Answer

Polycarbonate is significantly more impact-resistant than CR-39, making it the preferred material for safety eyewear and children's glasses.

ABO - American Board of Optometry Practice Test

ABO - American Board of Optometry Practice Test

ABO Ophthalmic Dispensing