Dispensing optician Exam

Dispensing optician Exam
Question 1: Which law describes the relationship between the angles of incidence and refraction when
light passes from one medium to another?
A) Huygens’ Principle
B) Snell’s Law
C) Newton’s Law
D) Fermat’s Principle
Answer: B
Explanation: Snell’s Law quantifies the bending of light as it passes between media of different refractive
indices.

Question 2: What is the phenomenon called when white light splits into its constituent colors after
passing through a prism?
A) Reflection
B) Refraction
C) Dispersion
D) Diffraction
Answer: C
Explanation: Dispersion occurs because different wavelengths of light refract by different amounts,
separating white light into a spectrum.

Question 3: Which term describes the point where parallel rays of light converge after passing through a
convex lens?
A) Center of curvature
B) Focal point
C) Principal axis
D) Optical center
Answer: B
Explanation: The focal point is where parallel light rays converge after refraction through a convex lens.

Question 4: How is the power of a lens measured?
A) In diopters
B) In lumens
C) In ohms
D) In pascals
Answer: A
Explanation: The power of a lens is measured in diopters, which is the reciprocal of the focal length in
meters.

Question 5: Which lens type is known to diverge light rays?
A) Convex lens
B) Concave lens
C) Plano lens
D) Cylindrical lens

,Answer: B
Explanation: Concave lenses spread out or diverge incoming light rays, making images appear smaller.

Question 6: What type of lens is used to correct myopia by diverging light before it enters the eye?
A) Convex lens
B) Concave lens
C) Cylindrical lens
D) Bifocal lens
Answer: B
Explanation: Concave lenses are used in myopia correction because they diverge light rays, allowing the
image to be focused correctly on the retina.

Question 7: Which lens material is known for its high impact resistance and is commonly used in safety
eyewear?
A) Glass
B) CR-39
C) Polycarbonate
D) High-index plastic
Answer: C
Explanation: Polycarbonate is favored for its superior impact resistance, making it ideal for safety
glasses.

Question 8: What is one disadvantage of glass lenses compared to plastic lenses?
A) Higher weight
B) Better UV protection
C) Increased impact resistance
D) Lower optical clarity
Answer: A
Explanation: Glass lenses are typically heavier than plastic lenses, which can be less comfortable for
prolonged wear.

Question 9: Which coating on lenses helps reduce reflections and glare from light sources?
A) Scratch-resistant coating
B) Anti-reflective coating
C) UV coating
D) Blue light blocking coating
Answer: B
Explanation: Anti-reflective coatings minimize reflections, enhancing visual clarity and reducing eye
strain.

Question 10: What is the primary benefit of a scratch-resistant lens coating?
A) Improves light transmission
B) Enhances cosmetic appearance
C) Increases durability
D) Adjusts focal length
Answer: C

,Explanation: Scratch-resistant coatings protect the lens surface from minor abrasions and extend the
lens’s longevity.

Question 11: What does UV coating on a lens primarily protect against?
A) Blue light emissions
B) Harmful ultraviolet radiation
C) Infrared radiation
D) Polarized light interference
Answer: B
Explanation: UV coatings are designed to block ultraviolet radiation, protecting the eyes from potential
damage.

Question 12: Which lens measurement is critical for aligning the optical center of a lens with the
patient’s pupil?
A) Vertex distance
B) Pupillary distance (PD)
C) Focal length
D) Segment height
Answer: B
Explanation: Pupillary distance (PD) ensures that the lens optical center aligns with the patient’s pupils,
essential for proper vision correction.

Question 13: What measurement is crucial for bifocal or progressive lenses to align the near segment
correctly?
A) Vertex distance
B) Segment height (seg height)
C) Base curve
D) Cylindrical axis
Answer: B
Explanation: Segment height is the vertical distance from the pupil center to the beginning of the near
segment in bifocal or progressive lenses.

Question 14: Which lens type is characterized by having two distinct powers for distance and near
vision?
A) Single vision lens
B) Progressive lens
C) Bifocal lens
D) Cylindrical lens
Answer: C
Explanation: Bifocal lenses have two distinct optical powers, one for distance and one for near vision
correction.

Question 15: What is a progressive lens designed to provide?
A) Only distance vision correction
B) A gradual change in prescription for a natural transition between distances
C) Only reading correction
D) Correction for astigmatism only

, Answer: B
Explanation: Progressive lenses offer a seamless progression of lens power for clear vision at multiple
distances without visible lines.

Question 16: What distinguishes spherical lenses from cylindrical lenses?
A) Spherical lenses have a uniform curvature, while cylindrical lenses have curvature in one axis
B) Spherical lenses correct astigmatism
C) Cylindrical lenses are always bifocal
D) Cylindrical lenses are used for reading only
Answer: A
Explanation: Spherical lenses have the same curvature across all meridians, while cylindrical lenses are
designed to correct astigmatism with curvature in one direction.

Question 17: Which lens material offers a thinner profile for higher prescriptions?
A) Standard CR-39 plastic
B) Polycarbonate
C) High-index plastic
D) Glass
Answer: C
Explanation: High-index plastic lenses are designed to be thinner and lighter for higher prescriptions
compared to standard materials.

Question 18: Which of the following is NOT a typical advantage of plastic lenses over glass lenses?
A) Lighter weight
B) Better impact resistance
C) Superior scratch resistance
D) Greater design flexibility
Answer: C
Explanation: While plastic lenses are lighter and more impact-resistant, they are generally more prone
to scratches compared to glass unless coated with a scratch-resistant layer.

Question 19: What is the term for the bending of light when it passes from one medium into another
with a different density?
A) Reflection
B) Refraction
C) Dispersion
D) Diffraction
Answer: B
Explanation: Refraction is the change in direction of light as it passes between media of different optical
densities.

Question 20: In lens terminology, what does the term “optical center” refer to?
A) The midpoint of the lens thickness
B) The point on the lens where light rays do not deviate
C) The edge of the lens
D) The focal point of the lens
Answer: B