ABO Practical Latest Version Already Passed

ABO Practical Latest Version Already Passed Single Vision corrects for one distance Multifocal Corrects with two or more prescriptions (or 'powers') Bifocal lens having two focus strengths Trifocal pertaining to having three focus strengths Calculating Prismatic Effects obtained at the center of an optical lens by producing a difference in edge thickness, either by grinding the back surface at an angle to the front surface during lens surfacing or, if the lens has sufficient power, de-centering the optical center of the lens Compounding Prism BI & BI BO & BO BU & BD Cancelling Prism BI & BO BD & BD BU & BU Prentice's Rule P=hcm x D P=amount of prism created h= number of cm OC moved cm= centimeters (convert to mm, divide by 10) D= power in meridian with error Vertical Imbalance The difference in vertical prism power at the reading level in a pair of lenses. OC Height's by lens SV = 1/2 of B Progressive = Fitting cross FT = 5mm above segment Vertex Compensation A plus lens when moved farther from the eye gains in plus power Distance is 0 with CL because they are on the eye Vertex compensation Formula De= Dl/(1 + d xDl) De= diopter effective value of error created D/= lens power (given power) d= amount in METERS lens moved from refracted position to position lens is worn Keep sign for what it is (+/-) - to d means moves away Horizontal Centration PD Vertical Centration OC Horizontal & Vertical Centration Formula Given PD/OC - Human PD/OC= mm moved Frame PD is found by adding A+DBL Power in Oblique Meridians Dt= (sina)²x Dc +Ds Dt= Total Power we need (sina)²= degree we have degree we need Dc= cylinder power Ds= sphere power Lensmeter is an ophthalmic instrument. It is mainly used by optometrists and opticians to verify the correct prescription in a pair of eyeglasses, to properly orient and mark uncut lenses, and to confirm the correct mounting of lenses in spectacle frames. (also known as a focimeter or vertometer) Lens Measurement Devices lens clock, calipers, millimeter ruler, circumference gauge Lens Clock is used to measure the surface powers base curve of a lens Lens Calipers Measures thickness of lenses in mm Millimeter ruler measures interpupillary distance, or seg heights, or OC heights Circumference gauge For quick and accurate measurements of lenses or patterns. Corneal reflex Pupilometer for precisely measuring and digitally recording pupillary distances. Used for measuring of monocular and binocular Hand Tools Screwdrivers, needle-nose pliers, tweezers, files scratchless screwdriver for working on drill mount or facetted lenses pickup screwdriver jaws with spring tension to hold screws while you put them in place, available with either type blade Big Brass screwdriver unscrew most screw, with a large brass handle plastic top screwdriver most popular and most dangerous Pad Popper used to remove snap-in nosepads without changing the alignment of the adjustable guard arms. the prongs are inserted behind the nosepad and in front of the nosepad box. a simple twist removes the pad Rimless mounting tool the hook is started at the hinge side of the nylon line that pulls around the lens. use caution, easy to chip lens eyewire sizing pliers used to check the size of the lens without damaging the barrels of the frame lens axis pliers allow you to turn the lens to adjust the axis while it is mounted in the frame Flat/round Nose Pliers used to change the curvature of pad arm loops. positioned so the loop is bent around the round tip Nylon Jaw flat/round nose pliers or Half-padded pliers they are used to protect the finish of metal frames during adjustments. nylon side should be positioned against the visible part of the frame Numont pliers used to hold eyewires of numont and nylon suspension frames during adjustment. you may also find them useful in adjusting the end pieces of narrow metal frames chappel cutting pliers he Chappel Cutting Plier cuts screw assemblies and reduces the risk of damaging lenses oblique cutting plier tips of these pliers taper to a 45 degree angle allowing you to get into small spaces B& L style adjusting pliers flat arm will work with pads whose mountings are flush against the pad European pad adjusting pliers designed specifically for screw and snap in type nosepad adjustment. box shaped indentation fits around the nosepad box. opposite jaw is curved to mimic the shape of the pad itself. curved arm is padded tp protect the pads when working with soft silicone pads temple angling pliers variety of jaw for adjusting the temples at hinge Nylon Eyewire forming pliers designed to form the eyewire of a metal frame to the curvature of the lens. can be used to curve the temple of the frame Nylon Jaw adjusting pliers especially good for adjusting metal frames and not marring the frame. great for two plier adjustments Tweezers great for working with tiny screws. useful for guiding nylon string (aka fishing line0 through small holes. available in different tip styles and grooves self-closing tweezers holds screws perpendicular to the tweezer body, works well on nose pad screws Zyl File Used to file plastic frames, good for rapid removal of material pillar file perfect for flat filing screw finishing or riffle file files screws without filing the frame slit file or screw head file for cleaning and restoring the screw head slots round or rat tail files for cleaning out or enlarging holes Screw extractors used in removing screws with stripped or broken heads. when using these come from the bottom of the hinge. there are sharp points that grip the broken screw to allow for removal Digital Measurement System takes measurements digitally for pd, seg height, and oc Orthoscopic Tilt ninety degree angle, resulting in no tilt retroscopic tilt bottoms of the eyewires sit out further from the face than the tops pf the eyewires pantoscopic tilt bottoms of the eyewires are in closer to the face than the tops of the eyewires splay angle nose pads are viewed from the top of the frame looking down, front edges of the pads are closer together than the back edges Frontal angle nose pads angle from the bridge center down along the length of the pad surface Vertical angle angle off vertical of a line down through the pad center as seen from the side Distometer An instrument for measuring vertex distance. Fitting traingle frame should touch at three points, the bridge and the skull at the crotch of each ear. the pressure at these points must be balanced and evenly distributed along the fullest possible contact area measuring bifocal segments from the bottom lid to the bevel of the frame measuring trifocal segments from the lower edge of the pupil to the bevel of the frame measuring progressive segments from the center of the pupil to the bottom of the frame A measurement horizontal frame depth B measurement vertical frame depth DBL distance between lenses, smallest linear measurement between lenses ED effective diameter, twice the longest radius of the lens C- size The circumference of the lens Datum Line 180 line, reference point for measurements DBC distance between centers, also referred to as the frame PD or FPD MRP Major Reference Point, same as optical center if no prescribed prism. the MRP or prism reference point (PRP) is the location on the lens that contains the prescribed refractive and prism correction minimum blank size smallest lens blank that can be used for a prescription lens in specific frame. depends on ED of frame Minimum Blank Size Formula M = ED + 2(d) + 2mm where ED is effective diameter d is the decentration per lens 2 is plus 2 mm for extra area Bridge pressure 90% of eyeglass weight too small bridge will cause irritation on the sides of the nose to large a bridge will put unnecessary pressure on the crest of the patients nose ear pressure 90% of adjustment to make it feel comfortable inverted triangle face shape consider getting frames slightly wider than your forehead for balance. Glasses with detailing on the lower portion of the frames are also a good option. Oval face shape any dark or light colored frames that are as wide as the broadest part of your face. Also, it is best to avoid any oversized frames. Round face shape stay away from rounded glasses and short frames. Instead, look for frames that will give contrast to your face such as square or angular shaped frames. Square face shape dark colored frames and oval eyeglasses to add contrast to your strong facial features. Consider staying away from geometric and square shaped frames and avoid any light colored frames. rectangle face shape soften your angular lines with rounder frames that are a little thinner. Also ensure the width of the frames is a little wider than your cheekbones. ANSI American National Standards Institute: A private, non-profit organization that coordinates the development and use of voluntary consensus standards in the United States. ASTM American Society for Testing and Materials EPA Environmental protection agency, an independent federal agency established to coordinate programs aimed at reducing pollution and protecting the environment OSHA Occupational Safety and Health Administration FDA Food and Drug Administration. The agency that is responsible for determining if a food or drug is safe and effective enough to be sold to the public. FTC Federal Trade Commission. Protects consumers from misleading and fraudulent advertising. Reviews advertising claims. Can order a company to change their ad