ABO ABO Industry Standards 2 — Questions and Answers
Question 1: According to ANSI Z80.1, what is the allowable tolerance for sphere power in single vision lenses with a power of ±0.25D to ±6.50D?
- ±0.06D
- ±0.13D (Correct answer)
- ±0.25D
- ±0.50D
Correct answer: ±0.13D
ANSI Z80.1 specifies a sphere power tolerance of ±0.13D for prescriptions between ±0.25D and ±6.50D.
Question 2: What does the term 'vertex distance' refer to in ophthalmic standards?
- The distance between the two lens optical centers
- The distance from the back surface of the lens to the cornea (Correct answer)
- The distance from the front of the lens to the spectacle frame
- The distance between the frame's datum line and the pupil
Correct answer: The distance from the back surface of the lens to the cornea
Vertex distance is the distance measured from the back (ocular) surface of the ophthalmic lens to the front of the cornea.
Question 3: Under ANSI Z87.1, occupational and educational eye protection must be marked with which designation to indicate basic impact resistance?
- Z87 (Correct answer)
- Z87+
- Z87-2
- Z80
Correct answer: Z87
The Z87 marking on safety eyewear indicates it meets ANSI Z87.1 basic impact requirements.
Question 4: What is the minimum refractive index required for a lens to be classified as 'high-index' by industry convention?
- 1.50
- 1.53 (Correct answer)
- 1.60
- 1.74
Correct answer: 1.53
By industry convention, lenses with a refractive index of 1.53 or higher are generally classified as high-index.
Question 5: Which ANSI standard governs the requirements for prescription ophthalmic lenses in the United States?
- ANSI Z80.3
- ANSI Z80.1 (Correct answer)
- ANSI Z87.1
- ANSI Z80.5
Correct answer: ANSI Z80.1
ANSI Z80.1 is the American National Standard for Prescription Ophthalmic Lenses and specifies optical and physical requirements.
Question 6: What is the ANSI-specified maximum allowable prism imbalance at the near reference point for a single vision lens with prescribed prism?
- 0.33Δ vertical / 0.67Δ horizontal (Correct answer)
- 0.25Δ vertical / 0.50Δ horizontal
- 0.50Δ vertical / 1.00Δ horizontal
- 1.00Δ vertical / 2.00Δ horizontal
Correct answer: 0.33Δ vertical / 0.67Δ horizontal
ANSI Z80.1 allows up to 0.33Δ vertical and 0.67Δ horizontal prism imbalance at the near reference point.
Question 7: A lens labeled 'UV400' blocks all ultraviolet radiation up to what wavelength?
- 380 nm
- 390 nm
- 400 nm (Correct answer)
- 420 nm
Correct answer: 400 nm
UV400 lenses block all UV radiation up to 400 nanometers, covering both UVA and UVB ranges.
ABO ABO Industry Standards 2
According to ANSI Z80.1, what is the allowable tolerance for sphere power in single vision lenses with a power of ±0.25D to ±6.50D?