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.
Full frame
Any frame in which the eyewire completely encircles to lens when properly mounted. 
Generating
The process of rapidly cutting the desired surface curvature onto a semi finish lens blank.
Generator
Lab equipment responsible for completing the generating process.
Geometric Center GC
Usually referring to the center of the frame eyewire determined during the boxing process.
Can also pertain to the center of a frame pattern.
Glare
Veiling glare interferes with visibility by causing a reduction in contrast.
This happens when a light source is reflected from a bright or transparent surface and objects become more difficult to see.
Glass
A form of crown glass used as a lens material. Must be heat or chemically treated in order to produce a impact resistant lens.
This treatment process, called “tempering”, is completed after the lens has been edged. Every lens must then pass an impact resistance test before continuing to spectacle assembly.
AKA: Crown glass
Other trade names:
Index of refraction: 1.523
Abbe: 59 (approx.)
Attributes:
Highest abbe value, most scratch resistant, heaviest of the materials, most chemical and heat resistant
Glazing
The insertion of lenses into a spectacle frame.
Grind
A “grind” or grind job usually refers to a lens that must be generated to fabricate the eyewear desired.
Grit
Referring to the texture or “roughness” of a pad used during the Fining process.
Hard Resin
A lens material otherwise known as CR 39.
Hide-a-bevel
bevel style that requires the lens bevel to be placed nearer to the front of the lens.
Hi Index
Lenses that are made with a plastic material which exhibits a Index of Refraction > 1.60.
Horizontal Plane
All lines parallel to the datum line.
Inspection (1st)
The stage of the lens fabrication process that requires the lab technician to inspect the lens for quality and accuracy; usually occurring at the end of the Surfacing stages and before the Finishing stages.
Infrared light rays IR
Invisible rays having wavelengths longer than those at the red end of the visible spectrum yet shorter than radio waves.
Lab job
Normally any pair of eyewear that needs to be fabricated at a complete full service lab that provides the surfacing process.
Lab software
A lab program that is used to assist in calculations and transmits information to lab equipment for the purpose of fabricating eyewear lenses.
Lab ticket
The work order produced by the lab computer with the calculated instructions for which the lenses of a particular pair of eyewear is to be fabricated by.
Layout and Blocking for finishing
Finishing Layout is referring to as the calculation and execution of decentering a lens for the purpose of edging.
Finishing Blocking is the process of bonding a metal or plastic disc (block) to the front surface of a finished or uncut lens for the purpose of lens edging. Afterwards the block is then clamped (chucked) into the edger with attached lens. The Blocking medium is normally a double-sided sticky pad referred to as a finishing pad or “leap” pad.
Layout & Blocking for surfacing
Surface Layout is referring to as the calculation and execution of decentering a lens for the purpose of surfacing.
Surface Blocking is the process of bonding a metal (usually) disc (block) to the front surface of a semi-finished lens blank for the purpose of lens power generation. Afterwards the block is then clamped (chucked) into the generator with attached lens. The Blocking medium is normally a metal alloy or wax.
Layout chart or grid
Layout charts are simple templates that allows the technician to recreate the PAL markings using a lens ink marker.
LEAP pad
A brand of adhesive pad by the 3M Company used during the finishing blocking process.
A brand of finishing pad
Lens Beveling
The process that finishes the lens edge to match and be fitting to the frame.
Lens Caliper
A hand-held width measuring device with a short graduated scale that slides along a longer graduated scale allowing a measure of fractional parts or decimals.
Lens Clock
A small, pocket-watch—sized instrument for measuring the surface curve of a lens.
Measures utilizing a scale in Diopters.
AKA: lens measure, lens gauge, Geneva Lens Measure
Lens Fining
In surfacing, the process of bringing a generated lens surface to the smoothness needed so that it will be capable of being polished.
Lens Generating
The process of rapidly cutting the desired surface curvature onto a semi-finished lens blank.
Lens Identifier
Progressive reference guide
Lens polishing
The last step in bringing a lens surface to its needed state of optical clarity.
Lens spotting
Referring to verifying and “dotting” a lens during 1st Inspection Stage prior to Layout and Edging Stages.
Longest radius LR
The measurement in mm from the GC to the farthest inside edge of the eyewire.
Marking of lenses stage (finishing)
The lensmeter has the ability to place three dot (spots) on the lens as part of the power, axis, and prism verification stage
Mechanical Center MC
The center of the lens in which it is edged around.
Mid-Index
A lens material that is a hybrid of CR-39 and Hi-Index exhibiting indexes of refraction and Abbe values between the two.
Minimum Blank Size (MBS)
The smallest lens blank that can be used for a given prescription lens and frame combination.
Formula: MBS = ED + ( 2 x monocular decentration)
Mires
The lighted straight lines in the lensmeter viewing area.
Neutralizer
A viscous fluid placed with the heated tints in its own separate container. Is used to lighten a tinted lens and performs a “bleaching” action.
Occupational Lens
A lens of particular design to assist the wearer with vision while preforming specific task(s).
Optical formula tutorial OFT
Optical Center OC
That point on an ophthalmic prescription lens through which no prismatic effect is manifested. No prism exists at the OC of a lens since the front and back surfaces of the lens are parallel.
OSHA (Occupational Safety and Health Administration)
The Occupational Safety and Health Administration (OSHA) is an agency of the United States Department of Labor. Congress established the agency under the Occupational Safety and Health Act, which President Richard M. Nixon signed into law on December 29, 1970.
PAL
Progressive Addition Lens
PAL identification tools
Since the laser engraved markings are usually small and often difficult to locate with the naked eye, several ophthalmic equipment producers have developed and offer tools to assist with this duty. These tools offer a combination of: -Magnification -Amplified light source -Background filter of varying contrast
Pattern
A plastic or metal piece having the same shape as the lens aperture for a given frame. Used in lens edging as a guide for shaping the lens to fit the frame.
PD stick
mm ruler
Photochromics
A lens that changes its transmission characteristics when exposed to light.
Plastic
CR-39
Point
1/10mm
Polariscope (polarimeter)
Optical inspection deviceused todetect internal stresses in glass and other transparent materials such as plastics, synthetic resins, etc.
Apolariscopeis composed chiefly of a light source and two crossed polarized lenses.
Polarization
Polarized lenses include a particular filter that blocks this type of reflected light and therefore reducing glare.
Polarized
A lens that includes a particular filter that blocks a type of reflected light in the attempt to reduce or eliminate veiling glare.
Polycarbonate
A non-glass lens material which inherently blocks UV.
AKA: “Poly”
Other trade names: Airwear, Featherweight, Slimlight,
Index of refraction: 1.586 or 1.59
Abbe: 29-32 (approx.)
Attributes: Very shatter resistant, lightweight, requires a SRC
Power Curves
Back surface curves of a meniscus design ophthalmic lens usually consisting of a back base curve and a cross curve.
PPE (Personal Protective Equipment)
– Specialized clothing or equipment worn by employees for protection against health and safety hazards. Personal protective equipment is designed to protect many parts of the body, i.e., eyes, head, face, hands, feet, and ears.
Prescribed Prism
A prismatic effect noted on the Rx prescribed by the doctor. To be verified at the lens’ PRP.
Prism Reference Point PRP
The point on a lens where prism power is to be verified. Previously referred to as the major reference point.
Protractor, lens
A millimeter grid on a 360-degree protractor used in the lens centration process for both surfacing and finishing
Reticle
The circles printed in the lensmeter viewing area.
Sag Meter
A measuring tool used to take a Sag measurement of a semi-finished blank.
Screwdriver, Flat-tipped
A tool with a flattened tip that fits into the head of a screw to turn it.
Screwdriver, Phillips tipped
A tool with a cross-shaped tip that fits into the head of a screw to turn it.
SDS (Safety Data Sheets)
The SDS includes information such as the properties of each chemical; the physical, health, and environmental health hazards; protective measures; and safety precautions for handling, storing, and transporting the chemical. The information contained in the SDS must be in English (although it may be in other languages as well).
Segment Drop
Difference between the datum line and the segment top.
Can be calculated by the Vertical Decentration formula.
Segment drop vs Segment height
Segment Drop is the vertical distance from the datum line to the top of the segment.
Segment Height is the vertical distance from the top of the segment to the deepest point of an edged lens.
Segment Height
The vertical measurement of the segment top center measured to the lowest point of the lens.
Segment Inset
The horizontal difference between the distance PRP and the near OC of the segment of a lens.
Semi-finished Lens Blank
A lens with only one side having the desired curvature. The second side must yet be surfaced to bring the lens to its desired power and thickness.
System for Ophthalmic Dispensing SFOD
Sizing plier
Sizing Pliershave points to hold the eyewire of your frame as tightly together. This allows the lab technician to decide if the lens has been edged to the correct size.
SRC (Scratch Resistant Coating)
Applied to: Polycarbonate-always Trivex-always Mid-Index-sometimes Hi-Index-sometimes CR-39-sometimes Glass-never
Surfacing Process
The process of creating the prescribed refractive power, prism, and prism reference point (PRP) location on a lens by generating the required curves and bringing the surface to a polished state.
Surface Saver Tape
A one-sided transparent or semi-transparent tape, approximately 4 inches in width, that is adhered to the front (F1) of a semi-finished blank before the surfacing block is mounted with alloy or wax. Its purpose is to protect the front curve surface of the lens during the surfacing process. When the block is removed after the polishing stage, it is removed as well and discarded.
SV Rx vs Multifocal Rx
A Multi-focal Rx includes a reading addition power usually rounded to the nearest +.25 dioptric power. Proper lab orders should contain two (2) sets of PDs and two (2) sets of fitting heights.
A Single Vision Rx does not contain a reading addition. Proper lab orders should contain only one (1) set of PD and fitting height.
All sets should be ordered Monocularly.
Tempering
Hardening
Tint
A shading of color added to the surface of a lens for a desired effect. Most often in solid or gradient in nature. Used normally to reduce light transmission of a lens. Also used for fashion purposes.
Top Liner
AKA: Figure-8 liner
Usually referring to the top nylon double cord that secures and holds the lens in place for a frame design signified as a Nylon Suspension Semi-rimless. The top portion of the cord secures into the top eyewire of the frame while the bottom portion of the cord protrudes and is purposed to fit into the top slot of a edged lens with a grooved bevel.
Trivex
The brand name for a PPG Industries plastic lens material known for its high impact resistance and ability to be processed in a manner similar to that of other plastic lenses.
Other trade names: Phoenix, Trilogy,
Index of refraction: 1.532 (approx.)
Abbe: 35-43 (approx.)
Attributes: Very shatter resistant, lightweight, tints well, requires a SRC
Ultrasonic cleaner
Ultrasonic Cleaners are electronic devices that use the power of ultrasound (ultrasonic sound waves) to delicately clean eyewear.
Unwanted Prism
Any prism in a pair of spectacles that is not noted on the physician’s Rx that could be interpreted as imbalance for the patient.
Uncut Lens
A lens that has completed the surfacing process but has not been edged for the frame.
UV (Ultraviolet light rays)
As we know there is UV A, B, and C.
Our Brooks & Borish textbook notes the wavelengths as:
UVA 315-380 nm
UVB 290-315 nm
UVC 200-290 nm
UV Protected
A lens that blocks, filters, or otherwise prohibits the ability of Ultraviolet light (200nm-380nm) to pass through its material.
Wet cut
Referring to a lens fabrication process, normally Generation or Edging, in which the equipment cuts the lens with a grinding wheel or lathe and requires water to be used as a coolant. Therefore the process is “wet”.
The water is either filtered and recirculated or immediately disposed.
Z80 (ANSI Z80)
ANSI Z80.1 applies to all prescription dress ophthalmic spectacle lenses in edged or assembled form. It is a guideline for entities that fabricate, assemble or process dress eyewear or lens components. Relevant optical and physical specifications and tolerances of this standard also apply to uncut lenses
ANSI Z80.3 is meant to “establish standards for noncorrective (essentially plano power) lenses that are intended for attenuation of light and for fashion eyewear, and for the flammability and durability of frames and lenses.”
ANSI Z80.20 applies to contact lenses worn over the front surface of the eye in contact with the preocular tear film. The standard covers rigid intracorneal and haptic (scleral) contact lenses, as well as soft paralimbal contact lenses.
Z87 (ANSI Z87.1)
The ANSI Z87.1 standard sets forth requirements for the design, construction, testing, and use of eye protection devices, including standards for impact and penetration resistance. All safety glasses, goggles, and face shields used by employees under OSHA jurisdiction must meet the ANSI Z87.1 standard. The eyewear standard includes the following minimum requirements:
- Provide adequate protection against the hazards for which they are designed
- Be reasonably comfortable
- Fit securely, without interfering with movement or vision
- Be capable of being disinfected if necessary, and be easy to clean Be durable
- Fit over, or incorporate, prescription eyewear
