Ophthalmic Optics Practice Exam

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• During lens edging, the optical center alignment is influenced by the relationship between patient PD and frame PD; what is the typical scenario?
• Thickness greater than 3.0 mm could indicate what kind of lenses?
• Are prism values for the right and left lens on a PAL measured at the same time, allowing use of paired prism rules?
• Which statement best describes the effect of increasing PAL power on the lens surface?
• The fitting cross on a PAL is a reference point for:
• In lensometry, when two prism measurements for the same eye differ, which value is used as the actual prism?
• The silver wheel is used for which purpose?
• When prescribing aspheric lenses, what type of frame should you recommend?
• True or False: When checking for vertical prism in lensometry, the prism values for each eye occur at the same time since we moved the position of the glasses?
• PRP is used to check prism on a PAL; what does PRP refer to?
• During edging, the optical center is shifted to align with which measurement?
• By convention, which prism value do we choose as the actual amount of prism when two values are measured?
• Minus lens center thickness around 2.2 mm could indicate which material?
• C-size refers to which aspect of the lens?
• When analyzing prism in a PAL, which approach should be used to determine the total prism for both eyes?
• The goal of choosing a lens blank is:
• How is total decentration calculated?
• To benefit patients with a minus prescription, aspheric lenses can thin the edge of a high minus lens, which is achieved by?
• For high plus lenses, the steeper the base curve, the __ the lens looks and the ______ the magnification.
• What is a lens blank?
• What percentage of spectacle wearers receive an astigmatism correction?
• What could happen if the segment height is too high?
• For measuring bifocal seg height, the reference line is drawn at which landmark?
• In hyperopes, non-aspheric correction vs aspheric correction magnification: Before using aspherics, hyperopes with non-aspheric correction were seeing the world ____% larger and with aspherics will now see the world ____% larger.
• Can prism be introduced by decentration in aspheric lens?
• The longest vertical height of the frame is called which measurement?
• What is the primary purpose of the bevel wheel in lens edging?
• When you increase power on a PAL, this creates:
• Which statement is true about the relation between base curve steepness and magnification in high plus lenses?
• In a plus aspheric lens with decreased center thickness, what change occurs to lens weight?
• For every prism diopter in a bifocal, you should adjust the seg height by:
• The term describing the distance between the lenses or bridge is which?
• How do you measure lens thickness?
• During the polishing process, what is used?
• During the fining process, what is used?
• Which specific lens aberrations does an aspheric lens help reduce?
• Where do you check for prism on a PAL?
• If you were to cut lenses in your office, how would the lens come?
• What does ED stand for in box system measurements?
• Increasing decentration will directly affect which component of MBS?
• If a person wanting bifocals walks tall, which seg height adjustment is appropriate?
• When lenses are cut to the shape of the frame, why aren't the blocks at the center of the lens anymore?
• The circumference of the edged lens is called?
• In a spherocylinder lens, which surface is toric?
• What length of a single lens should you account for the bevel?
• During fining, what happens to the backside of the lens?
• Why should you choose a small plus lens blank vs a larger plus lens blank?
• For a high minus lens with a large frame difference, where will the lens be thickest?
• Which thickness range is CR-39 typically associated with?
• Flatter lenses will allow the frame to sit closer to the eyes, and this effect reduces what?
• In a frame marking such as 50-18-140, what does the third number stand for?
• If there is BU over one eye, how should you adjust the seg height?
• When measuring PD for PALs, what type of PD should you be measuring?
• When a hyperope wears aspheric lenses, objects will appear:
• When edging in-office, what is the state of the back surface of the lens blank?
• The process of grinding a lens can also be referred to as:
• Which pair correctly completes the statement: The longest horizontal length is the frame measurement _____ and the lens measurement _____?
• Don't confuse _______ measurement with where the nose contacts the frame.
• Which statement is false about lens clocks and aspheric lenses?
• For children who need bifocals, where should the segment line be?
• Pantoscopic tilt helps align the optical axis with which reference to reduce aberrations?
• In frame measurements, the A measurement represents which dimension?
• The center of the 'box,' which isn't always at the optical center, is called what?
• If vertical prism is unacceptable, what other condition must be true?
• What is the term for the distance between the geometric centers?
• The silver wheel in lens finishing is used for which purpose?
• When measuring DBL on lenses that are in a frame, what should you do before recording the measurement?
• Which of the following is a main reason to choose an aspheric lens over a spherical lens?
• What is the purpose of pantoscopic tilt?
• If there is BD over one eye, how should you adjust the seg height?
• Which four values are needed to determine the minimum blank size (MBS)?
• In lens edging, which wheel is used specifically to create the bevel on the lens edge?
• Where should you set the distance when measuring PD for PALs?
• Why is it not recommended to just flatten the base curve of a spherical plus or minus lens?
• Which statement best describes an optical/cosmetic benefit of aspheric lenses?
• Aspheric curves can be placed on which surfaces now?
• What is the final finish described after polishing of the backside?
• How do you protect the lens blank during the surfacing process?
• Which statement about the weight and thickness of aspheric lenses compared to spherical lenses is true?
• The longest horizontal length of a single lens is called which measurement?
• Temple lengths are measured in ________ mm increments.
• If the desired frame is bigger than the frame you have on display, what should you do to adjust the seg height on the new frame?
• In an aspherical lens, which surface(s) flatten toward the edge?
• Which process step uses the roughing wheel?
• If the frame size the patient wants is 'wrong' for their seg height, which measurements should you compare?
• The distance between the lenses or bridge size is called what?
• If the desired frame is smaller than the frame you have on display, what should you do to adjust the seg height on the new frame?
• Most frames are designed to hold lenses with what power base curve?
• Name the 3 steps in surfacing.
• What are atorics?
• The center of the 'box' that isn't always at the optical center is called what?
• What type of curvature is needed to create an increasing plus power on PALS?
• During polishing, what is used?
• The measurement from the geometric center to the furthest edge doubled is called which term?
• During the creation of an aspheric lens, what happens to the back surface?
• In order to finish a lens, what is required?
• Where is the DBL measurement taken on a frame?
• When lenses are cut to the shape of the frame, the optical center is typically aligned with which reference?
• If a bifocal has 3 prism diopters, the seg height adjustment would be 1 mm. Which statement is true?
• Pantroscopic tilt is the tilt of the frame front relative to what reference plane?
• If the PD is smaller than the frame PD, what effect does this have on lens centering after shaping?
• If you want to order a blended bifocal, you should ______ the seg height.
• Another way to measure frame PD is:
• The box system dimension seldom used anymore is which measurement?
• Which wheel is primarily used to create the bevel on the lens edge during edging?
• Why are atorics used instead of standard aspheric lenses?
• What does it mean for a lens to be 'blocked' and what material is used?
• Aspheric curves used to be usually on which surface(s), but now they can be on which surface(s)?
• After shaping lenses to the frame, which factor most directly explains why the center of the lens may not coincide with the optical reference center?
• When measuring bifocal seg heights, draw a horizontal line on the lens at which landmark?
• Subtracting 0.5 mm from each DBL side is performed when measuring DBL for lenses that are in a frame.
• Which statement about lens blank thickness is true?
• What change is observed in lens volume when a plus aspheric lens has decreased center thickness?
• What is a practical reason to match frame PD to patient PD when prescribing aspheric lenses?
• If a plus aspheric lens has a decreased center thickness compared with the equivalent plus spherical lens, which other properties change?
• When verifying a prescription, horizontal prism is unacceptable if which condition is met?
• The roughing wheel is used for:
• In frame markings, what does the second number represent?
• Describe an aspheric lens.
• Which wheel is used to cut a bevel on the lens during edging?
• When ordering a bifocal for a child, seg height should be raised.
• How do you calculate minimum blank size (MBS)?
• Which surface is the front surface for aspheric spherical lens?
• Which description best fits a lens blank before edging?
• True or False: Not all progressives use aspheric optics.
• How do you prepare the lens blank for spherocylinder lenses?
• Which statement best describes when horizontal prism is considered unacceptable?
• If a person wanting bifocals is stooped, you should which seg height adjustment?
• True or False: Atorics technically have to be spherocylinders by definition, and don't include spherical lenses.
• Which statement accurately describes why the optical center may shift when lenses are cut to frame shape?
• Which magnification values correspond to hyperopes before and after aspheric correction?
• In a spherocylinder lens, which surface is toric?
• What is the sphericity of the front and back curves of an aspheric spherical lens?
• If you flatten the base curve of a spherical lens, what would the optics look like?
• How is a PAL created?
• Compared with an equivalent spherical lens, a plus aspheric lens with decreased center thickness tends to have what change in both lens volume and weight?
• When verifying a prescription, vertical prism is unacceptable if which condition is met?
• Which of the following statements is true about aspheric design in modern lenses?
• If you want to order a round seg, you should ______ the seg height.
• Which statement is true about round seg?
• Minus lens center thickness between 1.9 and 2.2 mm could indicate which material?
• The horizontal mid-line that intersects the midpoint of the B measurement is called which measurement?
• When fitting aspherics, how should you mark up the frame?
• During grinding, from which part is material removed?
• If the minus lens center thickness is less than 1.00 mm, what does that suggest about the glasses?
• What do the numbers 50-18-140 in a frame marking stand for?
• What is the rule for pantoscopic tilt?
• True/False: The DBL always matches the bridge size from the manufacturer.
• The larger the frame difference, the more _____________ the shape.
• How can prism be introduced in an aspheric lens?
• The frame difference is the difference between which measurements?
• Which items are required to complete lens finishing beyond the frame?
• Which statement best describes the effect of aspheric design on edge performance?
• What is the purpose of blocking during surfacing?
• Which statement describes blended bifocal seg height?
• For aspherics, should you measure monocular or binocular PDs?
• What defines atorics in terms of meridian flattening?
• The amount the frame front is tilted with reference to the plane of the face is called?
• In PAL fitting, what does the fitting cross help determine besides monocular PD?
• When adjusting seg height for a new frame, the difference in A or B measurements is halved. The halved difference is added or subtracted depending on whether the new frame is bigger or smaller.
• From which component do you read the larger prism component when checking for prism?
• Which box system value can be the same as the A-measurement?
• To measure lens thickness, where should the calipers be placed?
• Which PD type is used during PALs measurement?
• For a first-time trifocal wearer, where should the seg height be measured from?
• Which statement about the silver wheel is correct?
• Minus lens center thickness between 1 and 2 mm could indicate which material?
• This box system measurement is measured on the frame as the distance between the inside nasal eyewire grooves across the bridge area at the narrowest point.
• Which measurement describes the distance between the centers of the two lenses?
• Which term is used to denote the horizontal width across the frame commonly used as the eye size?
• High plus spherical lenses usually have ______ base curves.
• When fabricating lenses to fit a frame, which statement best explains why block placement may no longer be centered?
• Approximately 2.2 mm thickness is most likely which material?
• When checking for prism at the PRPs on a PAL, the values you obtain for the right and left lenses occur at the same time; therefore you should use the paired prism rules to determine the total amount of prism.
• If ED increases, what happens to MBS, assuming decentration remains constant?