NOCE Ophthalmic Products and Frames 4 — Questions and Answers
Question 1: Which type of anti-reflective (AR) coating layer is responsible for repelling water, oils, and smudges?
- The AR stack (alternating high/low index layers)
- The hydrophobic top coat (Correct answer)
- The hard coat base layer
- The UV blocking interlayer
Correct answer: The hydrophobic top coat
The hydrophobic top coat, also called an oleophobic layer, forms the outermost surface and repels water and oils to make lenses easier to clean.
Question 2: A patient reports that their acetate frame has become too tight after adjustment. What is the safest method to re-soften and reshape the frame front?
- Immerse in boiling water for 5 minutes
- Hold under cool running water for 30 seconds
- Use a frame warmer or salt pan at 140-160°F (60-71°C) (Correct answer)
- Use a heat gun set to maximum temperature
Correct answer: Use a frame warmer or salt pan at 140-160°F (60-71°C)
A frame warmer or salt pan at 140–160°F is the controlled, safe method to soften acetate for adjustment without scorching or warping.
Question 3: What does the term 'zygomatic arch adjustment' refer to in frame fitting?
- Aligning the optical center with the pupil
- Bending the temple to rest on the cheekbone rather than behind the ear
- Adjusting pantoscopic tilt to accommodate high cheekbones (Correct answer)
- Correcting the frame wrap angle
Correct answer: Adjusting pantoscopic tilt to accommodate high cheekbones
A zygomatic (cheekbone) adjustment involves modifying the pantoscopic tilt or frame fit to account for a patient's prominent cheekbones that affect how the frame sits.
Question 4: Which lens material is MOST impact-resistant and is required by ANSI Z87.1 for occupational safety eyewear?
- CR-39 plastic
- Crown glass
- Polycarbonate (Correct answer)
- High-index 1.67
Correct answer: Polycarbonate
Polycarbonate is the most impact-resistant common ophthalmic material and meets ANSI Z87.1 requirements for occupational safety eyewear.
Question 5: A frame's eye size is 54, DBL is 16, and the patient's PD is 64 mm. What is the decentration per lens needed for proper optical alignment?
- 3 mm temporal decentration per lens (Correct answer)
- 3 mm nasal decentration per lens
- 1 mm temporal decentration per lens
- No decentration is needed
Correct answer: 3 mm temporal decentration per lens
Frame PD = (54/2) + 16 + (54/2) = 70 mm; patient PD = 64 mm; difference = 6 mm total, so 3 mm temporal decentration per lens is required.
Question 6: What type of lens treatment selectively absorbs specific wavelengths of blue-violet light while allowing beneficial blue-turquoise light to pass?
- Photochromic coating
- Selective blue light filtering (blue-light blocking) coating (Correct answer)
- Polarizing filter
- Anti-reflective stack only
Correct answer: Selective blue light filtering (blue-light blocking) coating
Selective blue light filtering coatings are designed to block harmful blue-violet light (around 415–455 nm) while allowing beneficial blue-turquoise light (~480 nm) to pass.
Question 7: A patient's titanium frame temple has snapped at the hinge. What property of titanium makes soldering this repair particularly challenging?
- Titanium's low melting point causes rapid deformation
- Titanium requires an inert gas atmosphere during welding to prevent oxidation (Correct answer)
- Titanium's high Abbe value increases optical aberrations
- Titanium is magnetic and deflects standard soldering tools
Correct answer: Titanium requires an inert gas atmosphere during welding to prevent oxidation
Titanium reacts with oxygen and nitrogen at high temperatures, requiring an inert gas (argon) atmosphere or laser welding to make a clean, strong repair.
NOCE Ophthalmic Products and Frames 4
Which type of anti-reflective (AR) coating layer is responsible for repelling water, oils, and smudges?