CPOT CPOT Optical Dispensing & Lens Technology 2 — Questions and Answers
Question 1: A patient's prescription reads +3.00 sphere. This patient is corrected for:
- Myopia (nearsightedness)
- Hyperopia (farsightedness) (Correct answer)
- Astigmatism
- Presbyopia
Correct answer: Hyperopia (farsightedness)
A plus sphere power corrects hyperopia by adding converging power to focus light on the retina for a farsighted eye.
Question 2: Polycarbonate lenses are often recommended for children and safety eyewear primarily because of their:
- Superior optical clarity
- Highest Abbe value
- Impact resistance and lightweight nature (Correct answer)
- UV absorption without coating
Correct answer: Impact resistance and lightweight nature
Polycarbonate is highly impact-resistant and lightweight, meeting ANSI Z87.1 safety standards, making it ideal for children and occupational eyewear.
Question 3: When verifying a finished pair of glasses with a lensometer, the technician is checking for:
- Frame alignment only
- Lens power, axis, prism, and optical center placement (Correct answer)
- Pupillary distance only
- Lens color and coating quality
Correct answer: Lens power, axis, prism, and optical center placement
The lensometer (focimeter) measures the sphere and cylinder power, axis orientation, prismatic effect, and optical center location of finished lenses.
Question 4: UV-absorbing lenses help protect the eye from solar radiation that can contribute to:
- Presbyopia and glaucoma
- Cataracts and macular degeneration (Correct answer)
- Myopia progression and dry eye
- Color blindness and night blindness
Correct answer: Cataracts and macular degeneration
Chronic UV exposure is a known risk factor for both cortical cataracts and age-related macular degeneration, making UV protection a key dispensing recommendation.
Question 5: Photochromic lenses darken when exposed to UV radiation because they contain:
- Polarizing filters
- Photosensitive molecules such as silver halides or organic compounds (Correct answer)
- Anti-reflective multilayer coatings
- Tinted pigments baked into the substrate
Correct answer: Photosensitive molecules such as silver halides or organic compounds
Photochromic lenses contain photosensitive compounds that undergo a reversible chemical reaction upon UV exposure, causing the lens to darken.
Question 6: Prism in ophthalmic lenses is measured in units called:
- Diopters
- Prism diopters (Δ) (Correct answer)
- Millimeters
- Radians
Correct answer: Prism diopters (Δ)
Prism power is measured in prism diopters (symbol Δ), where 1 prism diopter displaces an image 1 cm at a distance of 1 meter.
CPOT CPOT Optical Dispensing & Lens Technology 2
A patient's prescription reads +3.00 sphere.
This patient is corrected for: