ABO NOCE Basic Opticianry General Practice 2 — Questions and Answers
Question 1: A patient's prescription reads +2.50 -1.00 x 090. What is the spherical equivalent?
- +2.00 (Correct answer)
- +3.00
- +1.50
- +2.50
Correct answer: +2.00
Spherical equivalent = sphere + (cylinder/2) = +2.50 + (-0.50) = +2.00.
Question 2: Which frame measurement represents the longest horizontal dimension of a single lens aperture?
- A measurement (eye size) (Correct answer)
- B measurement (depth)
- DBL (bridge)
- ED (effective diameter)
Correct answer: A measurement (eye size)
The A measurement is the horizontal width of one lens opening in the frame.
Question 3: Prentice's Rule states that prismatic effect (in prism diopters) equals:
- Power (D) × decentration (cm) (Correct answer)
- Power (D) × decentration (mm)
- Power (D) / decentration (cm)
- Decentration (mm) / power (D)
Correct answer: Power (D) × decentration (cm)
Prentice's Rule: Δ = P(D) × d(cm); decentration must be expressed in centimeters.
Question 4: When transposing a minus-cylinder prescription to plus-cylinder form, the new axis is:
- Original axis ± 90° (Correct answer)
- Original axis unchanged
- Original axis + 45°
- Original axis − 45°
Correct answer: Original axis ± 90°
Transposition to the opposite cylinder form requires rotating the axis by 90 degrees.
Question 5: A frame marked 54-18-140 has what bridge size?
- 18 mm (Correct answer)
- 54 mm
- 140 mm
- 36 mm
Correct answer: 18 mm
In standard frame notation (eye size–bridge–temple length), the middle number (18) is the bridge width.
Question 6: What is the primary purpose of selecting a base curve for a spectacle lens?
- To minimize peripheral aberrations and fit the frame design (Correct answer)
- To determine the add power
- To set the optical center height
- To establish segment position
Correct answer: To minimize peripheral aberrations and fit the frame design
Base curve selection is guided by the need to minimize oblique astigmatism and other off-axis aberrations.
Question 7: Which condition is characterized by reduced near vision due to decreased accommodative amplitude associated with aging?
- Presbyopia (Correct answer)
- Hyperopia
- Astigmatism
- Myopia
Correct answer: Presbyopia
Presbyopia is the age-related loss of accommodation that reduces the ability to focus at near distances.
ABO NOCE Basic Opticianry General Practice 2
A patient's prescription reads +2.50 -1.00 x 090.
What is the spherical equivalent?