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

1.0 mm for all lenses

Answer

3.0 mm for polycarbonate

Answer

0.5 mm for trivex

Question 2

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

Accepted Answer

High-index 1.74 plastic

Answer

Crown glass (1.523)

Answer

Polycarbonate (1.586)

Answer

CR-39 (1.498)

Question 3

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

Accepted Answer

Fitting height

Answer

Pupillary distance

Answer

Pantoscopic tilt

Answer

Frame wrap angle

Question 4

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

Accepted Answer

Eye size (A dimension)

Answer

Bridge size (DBL)

Answer

Temple length

Answer

B dimension

Question 5

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

Accepted Answer

Superior impact resistance

Answer

Better optical clarity

Answer

Higher Abbe value

Answer

Easier to tint

Question 6

When is it appropriate to use a slab-off prism?

Accepted Answer

To correct vertical imbalance in anisometropic patients wearing multifocals

Answer

To correct horizontal phoria

Answer

To reduce lens thickness in high minus prescriptions

Answer

To improve cosmetic appearance of thick lenses