ABO NOCE Basic Opticianry ABO NOCE MCQ 2 — Questions and Answers
Question 1: A patient's prescription reads +2.50 -1.25 x 090. What is the sphere power of the lens?
- +2.50 D (Correct answer)
- -1.25 D
- +1.25 D
- +3.75 D
Correct answer: +2.50 D
The sphere power is the first number in the prescription notation, which is +2.50 D.
Question 2: Which lens design is best suited for a patient who needs to read music on a stand while playing an instrument?
- Intermediate single vision
- Progressive addition lens
- Bifocal with round seg
- Occupational progressive lens (Correct answer)
Correct answer: Occupational progressive lens
Occupational progressives are designed for intermediate-dominant tasks, providing a wider intermediate zone ideal for music stand distances.
Question 3: What does the term 'decentration' refer to in opticianry?
- Moving the optical center away from the pupil center (Correct answer)
- Adjusting the vertex distance
- Changing the lens base curve
- Increasing the pantoscopic tilt
Correct answer: Moving the optical center away from the pupil center
Decentration is the intentional horizontal or vertical displacement of the optical center relative to the frame's geometric center.
Question 4: A frame has a 'B' measurement of 38 mm and a DBL of 18 mm. What is the frame's 'A' measurement needed to calculate minimum blank size?
- It cannot be determined from B and DBL alone (Correct answer)
- 56 mm
- 20 mm
- 38 mm
Correct answer: It cannot be determined from B and DBL alone
The 'A' measurement (lens width) is independent of B (lens height) and DBL (bridge width) and must be measured separately.
Question 5: Which of the following coatings reduces reflections from the back surface of a lens to improve night driving vision?
- Anti-reflective coating (Correct answer)
- Photochromic coating
- UV coating
- Scratch-resistant coating
Correct answer: Anti-reflective coating
Anti-reflective (AR) coating minimizes internal and external reflections, reducing halos and glare especially during night driving.
Question 6: What is the effect on image size when minus lenses are used?
- They minify the image (Correct answer)
- They magnify the image
- They have no effect on image size
- They distort the image vertically
Correct answer: They minify the image
Minus (concave) lenses cause light to diverge, producing a smaller, virtual, and upright image — a minification effect.
Question 7: A patient complains that their new single vision lenses cause the floor to appear to tilt. Which measurement error is most likely responsible?
- Unequal optical center heights (Correct answer)
- Incorrect pupillary distance
- Wrong base curve
- Improper lens material selection
Correct answer: Unequal optical center heights
Unequal optical center heights create vertical prismatic imbalance, causing spatial distortion that makes flat surfaces appear to tilt.
ABO NOCE Basic Opticianry ABO NOCE MCQ 2
A patient's prescription reads +2.50 -1.25 x 090.
What is the sphere power of the lens?