Chapter 12: Fundamentals of Practical Opticianry

Question 1

Opticianry

Answer 1

Specialized area of eye care that includes the making of corrective lenses from refractive prescriptions and the fitting of both the lenses and the eyeglass frames for proper visual correction

Question 2

Types of Corrective Lenses

Answer 2

1) Single-vision Lenses- typically only correct for a single distance point (either distance or reading)
2) Multifocal Lenses- correct for multiple distance points (distance and reading)

Question 3

Bifocal Lens

Answer 3

A lens that has 2 powers: usually one for correcting distance vision and one for correcting near vision

Question 4

Trifocal Lens

Answer 4

One that has 3 powers: one for correcting distance vision, one for correcting intermediate vision, and one for correcting near vision

Question 5

Segment

Answer 5

The portion of the bifocal or multifocal lens that provides correction for near vision
Also called Segment or Near Add

Question 6

Executive

Answer 6

Refers to a bifocal lens consisting of a top distance band and bottom near band that divides the entire width of lens into 2 parts
Also called lined bifocal
Advantage: very clear which portion of the lens a patient needs to use for certain tasks

Question 7

Round-Top Segments

Answer 7

A portion of a circle fused or ground into a distance lens for near vision; may be used in bifocal or trifocal

Question 8

D Segment

Answer 8

A portion of bifocal or trifocal lens; so called because it is shaped like the letter D lying on its side

Question 9

Progressive Addition Multifocal Lenses

Answer 9

A spectacle lens with multiple areas of different focal points with no discrete visible lens dividing the various segments; rather, the optical power is added progressively in a transitional manner
Advantages: clear vision at all distances, more fashionable

Question 10

Invisible Bifocals

Answer 10

A bifocal lens with a softened or blended transitional zone between the segment and the distance portion
These are not the same as Progressive bifocals

Question 11

Double-D Segment

Answer 11

A multifocal lens with the distance correction in the middle, a traditional near-power D segment at the bottom, and an intermediate-power inverted D segment at the top, commonly used by individuals with vocational needs for intermediate correction in upgaze such as mechanics and boaters

Question 12

CR-39

Answer 12

A common plastic lens material with an index of refraction

Question 13

Polycarbonate

Answer 13

A common plastic safety lens material that is resistant to shattering

Question 14

Photochromic Lenses

Answer 14

Refers to a lens specially manufactured to be sensitive to ultraviolet light, so that it darkens in sunlight and lightens when not in sunlight

Question 15

Polarized Lenses

Answer 15

A specialized lens that reduces glare from a horizontal reflecting surfaces and protects against UV rays

Question 16

Antireflective Lens Treatments

Answer 16

A treatment that reduces or eliminates reflections from the surface of a lens

Question 17

Interpupillary Distance

Answer 17

The distance from the center of one pupil to the center of the other pupil

Question 18

Optical Center

Answer 18

The point of optimal vision; the single point of a lens through which light may pass without being bent or changed

Question 19

Vertex Distance

Answer 19

The distance from the back surface of the lenses to the front surface of the eye
Measured by a distometer

Question 20

Base Curve

Answer 20

The curve of the lens surface, usually the outer or front side of the lens, from which the other curves necessary for sight correction are calculated

Question 21

Orthophoric

Answer 21

Refers to the absence of strabismic deviation; normal

Question 22

Distance between Optical Centers

Answer 22

The distance between the optical center of the right eyeglass lens and the optical center of the left lens; Corresponds to interpupillary distance

Question 23

Prismatic Effect

Answer 23

An optical distortion in which images are displaced from their normal position. This can occur if the distance between optical centers does not correspond to the interpupillary distance

Question 24

Digital Corneal Reflection Pupillometer (DCRP)

Answer 24

An instrument that monocularly measures interpupillary distance

Question 25

Distometer

Answer 25

An instrument that measures the vertex distance

Question 26

Geneva Lens

Answer 26

An instrument for measuring the base curve of an eyeglass lens

Question 27

Pantoscopic Angle

Answer 27

The angle of an eyeglass frame by which the frame front tilts from the vertical plane when the glasses are worn

Question 28

Retroscopic Tilt

Answer 28

The tilt of an eyeglass frame adjusted so that the lower rim tilts away from the face

Question 29

Segment Height

Answer 29

The distance between the lowest part of an eyeglass rim and the top of the multifocal lens segment