Terminology Flashcards
First inspection stage
Inspection of all the work from the previous stages of the surfacing process.
If the lens passes, it qualifies to continue to the rest of the finishing process.
If the lens fails, this inspection stage is disregarded and the servicing process for the job order begins again.
3 piece chassis
The frame portion of a drill mounted style of eyewear
“A”measurement
Horizontal width
ABBE number
Most commonly used number for identifying the amount of chromatic aberration for a given lens material.
A higher ABBE value, the less chromatic aberration present in the lens.
The lower ABBE value, The more likely it will be that color fringes will be seen through the lens and that visual acuity will be reduced in the periphery of high powered lenses.
ANSI
American National Standards Institute
Anti-reflective coating
A thin layer or a series of layers of material applied to the surface of a lens for the purpose of reducing unwanted reflection from the amount of light that passes through to the eye.
Anti-slip pad
Small decal or sticker apply to the lens during the finished blocking stage.
ASTM
American society for testing and materials.
ASTM F803
Standards for eye and head protection in many sports.
“B” measurement
Vertical height
Blue dot
Slang for a style of anti-slip pad.
Bottom liner
Usually referring to the bottom nylon single cord that secures and holds a lens in place for the frame design (semi rimless)
Bottom clear wire on semi rimless frames.
Box - o - graph
A flat device containing grids and slides, used in the measurement of pattern and edged lens size. 
Bring down
Slang For reducing the diameter or size of a lens during the edging process.
“C” measurement
Horizontal width of a lens at the datum line
Chiller
Machine that removes heat from a liquid via a vapor compression or absorption refrigeration cycle. 
Chromatic aberration
Type of aberration that causes light of softener wavelengths (colors) to be refracted differently through the same optical system.
Chuck
Normally referring to the clamp that holds the lens during the generating or edging processes.
Coater
Machine that applies and cures the scratch resistant coating lenses during the surfacing process.
Color dispersion
White light is separated into color components upon passage through the prism.
Compression mounting
Rimless frame in which nylon bushings and barbed posts are used to mount the lenses to the chassis instead of the traditional screw mounting system.
Computer system for lab
Program that processes the info it is given to correctly instruct the lab equipment on how to process a lab job.
Concave curve
An inward curved surface
Convergence
Usually referring to the patients inward turning of the eyes when looking at a near object.
Convex curve
An outward curves surface
Cr-39
Pittsburg Plate Class Co.
Columbia Resin 39 - Plastic/ hard resin Index of refraction: 1.49 or 1.50
Other names: Orma
ABBE: 58
Fairly scratch resistant, normal shatter resistance, tints well
Crazed
Cracked appearance of a lens with a damaged or defective coating
Cribbing
Process of reducing a semi finished lens blank to a smaller size to speed the surfacing process or reduce the probability or difficulty.
Usually done during the generation stage.
Cylinder
Cross curve in the back of a lens
Cylinder machine
Equipment responsible for completing the fining and polishing processes.
Datum line
Line drawn parallel and halfway between the horizontal lines tangent to the lowest and highest edges of the lens.
Decentration
Movement of the lens PRP, segment, or fitting cross away from the frames GC prior to the generation or edging process to obtain a desired effect.
Defect
An imperfection in a lens , frame, or completed pair of spectacles that will prevent it from passing an inspection prior to dispensing it to the patient.
Distance between centers DBC
Horizontal distance between the GC’s of a frame front. (Frame PD)
Distance between lenses DBL
Bridge size
DPD, IPD, and NPD
DPD: Distance Pupillary Distance or the patient (Far)
IPD: Intermediate Pupillary Distance of the patient (Specific use)
NPD: Near Pupillary Distance between of the patient (reading)
Drill mount
Frame style which the lenses are drilled with holes through which they are mounted and secured to the frame chassis.
Drop - Ball Test
A test to determine the impact resistance of ophthalmic lenses whereby either a 5/8” or 1 inch steel ball is dropped onto the front surface of the lens from a height of 50 inches.
Dry cut
Referring to a lens fabrication process, normally generation or edging, in which the equipment cuts the lens with a blade and does not require water to be used as a coolant. Therefore the process is “dry”.
Edging
Cutting the finished lens blank to a size and shape that will fit the desired frame.
Finished lens is sometimes referred to as uncut.
Edging pad
A double sided adhesive pad used to attach the finishing block to the front of an uncut lens for the purpose of edging.
Effective Diameter ED
Twice the longest radius of a frames lens aperture as measured from the boxing center.
ED= longest radius x 2
EOOLF
Essentials of ophthalmic lens finishing book
EPA
Environmental protection agency
Eyewire
The rim of the frame that goes around the lenses.
FDA
Food and Drug administration
Final Inspection
The last inspection of a pair of spectacles for accuracy and quality assurance before it is released from the lab.
Finishing process
The process in the production of spectacles that begin with a pair of uncut lenses of the correct refractive power and ends with a completed pair of spectacles.
Finished lens blank
Lens that has front and back surfaces ground to the desired powers, but not yet edged to the shape of the frame .
Fitting cross
Location on the lens which is used to verify the fit and should be positioned at the center of the patients pupil. During the final inspection stage, the patients PD and fitting height should be measured and verified here.
Fitting height
The vertical measurement of the PRP measured to the lowest point of the lens.
On a progressive lens this location is a fitting cross and not the PRP.
Frame style/ design
Specifics of eyewear frame construction involving materials used, fashion, lens shape, and lens mounting technique.
Frame tracer
Instrument used to physically trace the inside groove of a frames lens opening or the outside edge of a lens for the purpose of creating a digitized shape.
Frame warmer
A device that blows air and used to heat plastic spectacle frames in order to soften its material suffering to allow insertion of lenses and/or adjustment.
Front Base Curve
B.C.
Surface curve of a lens that becomes the basis from which the other remaining curves are calculated.
This is usually the front curve of the lens.
Front sag measurement
Sagittal depth
The front sag measurement is that of a lens front curve or F1.
The unit of measure for the sag is called radians or rads.