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abo exam
optician
| Question | Answer |
|---|---|
| RX : +4.50 +.50 x180 +2.00 +.25x90 add +1.75 What is the vertical imbalance at a 10 mm reading level? | 3.0 prism diopters |
| The slab-off lens design utilizes base up prism in the lens with the ______ in the vertical meridian. | Most minus power |
| When calculating vertical prismatic imbalance, all of the following need to be considered EXPECT | Reading addition |
| During final inspection, it was determined the optical centers of the lenses were placed 63 mm apart. How much total prism will this produce and in which direction is the base? | 1.0 prism diopters base in +2.50 x.2cm =.5 bi +2.50x.2cm=.5bi add equals 1.00 base in |
| If the rx -3.00+.50 x90 is decentered out 2 mm to much , how much prism will be created, and in which direction is the base? | .50 prism diopter base in -2.50x.2cm=.5 bi |
| RX: +2.00-4.00x45 How much prism will be created if the optical center of this lens is received 5 mm to narrow? | none (plano) |
| Looking out from the optical center of a minus lens creates base ____ prism | out |
| A reverse slab off is done on the lens with ______ in the 90th meridian | Most plus/least minus |
| What is the vertical imbalance of the following Rx at the reading level of 10 mm? -1.50 -1.00x90 -4.00-1.00x120 +3.00 add | 2.75 diopters |
| What is the image jump, using Rx -1.50-1.00x90 -4.00-1.00x120 +3.00 add if wearing a ft 28(5 mm) segment ? | 1.5 prism diopters |
| A-3.00 lens decentered 2 mm creates _____ diopters of prism | .6 diopters |
| rewrite the rx below to make better balanced lens od -1.00-.50x90 3.00 bu os -1.25-.50x901.00bd | -1.00-.50x902.00 bu -1.25-.50x90 2.00 bd |
| The PD written on the order is mistakenly noted at 68 mm , when actual measurement should be 66 mm. What is the unwanted prism if the rx :15.oo ou? | 1.5 out each eye |
| a patient is looking 4 mm below the distance optical center of the following rx. What is the prismatic effect and direction? +3.00-1.00x180 | .8 base up +2.00x.4=.8 |
| When prism is prescribed to correct a muscle imbalance, where is the base placed? | Over the strong muscle |
| What type of prismatic effect is easiest to tolerate at the near point? | base in |
| Excessive base up prism | makes people feel like they are walking down hill |
| If a prism can deviate a ray of light 2 cm at a distance of 4 m what would be it power? | 1/2 diopter |
| If the pupillary distance is measured while the patient is focusing at a point 16 inches in front of his eyes, the PD being measured is known as ? | Near |
| To mount a lens in a three piece frame it would be necessary to ____ the lens | Drill |
| It is "generally" accepted to fit the top of the bifocal segment to the ? | edge of the lower lid margin |
| When aphakic lenses slide down the patient's nose what can be expected to occur? | error in refractive power |
| Slab off is used as a means of correcting vertical imbalance at the reading level. Regular slab off grinds prism in which direction in the lens? | up |
| a multifocal height is usually determined by measuring from the ? | top of the segment line and to the deepest point of the eye wire |
| If a frame does not have enough pantoscopic tilt, the adjustment to make is? | angle the temples downward from the endpiece |
| a metal frame mounting consists of | a front,Pads,pad arms, bridge,eyewires, and temples |
| To narrow the distance between the pads of a frame or mounting , bend the pad arms? | inward |
| Aphakic patients wearing strong cataract lenses would find which of the following fitting techniques most beneficial? | small eyesize frames, a short vertex distance; aspheric front surface lenses |
| As the pantoscopic angle is increased? | cylinder is induced at axis 180 |
| When prism is used for vision therapy to correct a muscle imbalance for esotropia the prism base would be? | base in prism |
| Bowing the temples is an expression referring to ? | curving the temples around the head |
| When adjusting the frame, the bifocal height can be using the following adjustment? | using more pantoscopic tilt |
| To relieve pressure causing soreness at the front edge of the nose pads so the posterior and anterior edges of the pads have even pressure, a good adjustment would be ? | flare pads out more (spread back edges apart more) |
| If the pads are bent down the adjustment will? | drop the front |
| If the pads are brought closer together this adjustment will? | raise the front |
| If the left temple is angled out, the adjustment will? | Bring left side of front toward the left eye |
| To relieve tension on both ears; a good adjustment would be to? | lengthen both temples |
| The type of bridge on a plastic frame designed to rest entirely on the nose is the? | Saddle |
| The plier best used for adjustment of the endpiece is the? | End piece plier |
| When fitting high power lenses certain critical measurements are taken. they include? | monocular pupillary measurements and vertical placement of optical center |
| Which multifocal style offers a clear focal point at any distance | Progressive |
| indicate the amount of conventional slab off needed to neutralize the vertical prismatic imbalance. the reading level is 10 mm RX -5.00-.50 x180 -2.75 -.75x180 add +2.50 | 2.0 prism diopters bu ou (-5.50x1cm=5.50) -3.50x1cm=3.5 (slab off is always base up) |
| an uncut lens must be at least____ mm in diameter to allow cutting of a 48 mm round lens decentered at 4 mm in | 56 (2x4+48=56) |
| in the boxing system the "B" measurement represents | lens depth Vertical |
| A +3.00 lens has a +7.25 base curve. the ocular (back) surface curve is? | -4.25 +7.25-3.00=4.25 |
| Transposition shows? | lens power in the principal meridians |
| Common ophthalmic crown glass has an index of refraction of ? | 1.523 |
| Opposite refractive errors in the two eyes is called ? | Antimetropia |
| The area where the upper and lower eyelids meet is called the | Canthus |
| An area on the retina 3mm to 5mm in diameter, usually located temporally to and slightly below the level of the optic disc and contains the fovea is called? | macula |
| A tendency of the eye to turn | ptsois |
| Looking above the optical center of a plus lens creates base ___ prism. | Down |
| A localized yellowish-gray elevated mass in the conjunctiva | Pinguecula |
| A retinoscope is used to ? | measure refractive error |
| A-500 lens decentered in 4 mm produces? | 2.0 base in |
| The eye is most sensitive to the portion of the electromagnetic spectrum that includes | Components of white light |
| The part of the eye that detects color under normal illumination | Cones |
| Fusion of the ocular images occurs | in the optic chiasm |
| An advantage of a flat top bifocal over a round bifocal is | into the useable area of segment faster |
| the index of refraction of cr -39 is | 1.49 |
| the index of refraction of poly is | 1.586 |
| The specific gravity of crown glass is? | 2.54 |
| The wavelength of visible light range from | 500-- 800 nanometers |
| The breakdown of light into its component colors is called | Dispersion |
| The point on a lens which a ray of light will pass through being deviated is called? | Optical center |
| The lower abbe number the? | More the chromatic aberration |
| The cylinder axis tolerance for a 2 .00 diopter cylinder for prescription ophthalmic lenses is? | 2 degrees |
| The prism tolerance for a mounted pair of eyeglasses in the vertical meridian is | 1/3 prism diopter ansi standard |
| the tolerance for lens thickness when specified for special prescription purposes is? | .3mm |
| The tolerance for specified base curve is? | 1.00 diopter |
| The segment location tolerance in the vertical (segment height) meridian in a mounted pair of eyeglasses? | segs should match within 1.0mm of specification |
| The tolerance of the cylinder axis of the right lens is OD +2.00+2.00x90 os +3.00+1.00x180 add +200 ou ft 25 | 2 degrees |
| The reading rx for -4.25 -1.25x90 +2.00 add is | -3.50 +1.25x180 |
| To ensure that no details are missed when verifying a completed pair of lenses use? | A final inspection list |
| If your lensometer reads -.25 with no lens, a lens that measures -3.00-1.50x180 is actually? | -2.75-1.50x180 |
| A lens surface measuring +6.00 and +6.50 in each of the primary meridians is ? | Aspheric |
| Why is it important to give realistic delivery times for new glasses? | if you understate delivery time and glasses are delayed patient will be disppointed |
| In which of the following cases should you consult the refractionist about the RX | New rx +2.00-1.00x90 +.75-1.25x90 old rx -2.25-1.00x90 -1.00-1.00x90 |
| The fibrous tunic is comprised of the | iris, ciliary body, and choroid |
| Rods and cones are found? | retina |
| The Aqueous humor is continually being manufactured by ? | the ciliary body |
| The ability of the eye to bring objects of varying distances to focus on the retina is known as? | Accommdation |
| When accomondation is at rest, rays of light from a distance source come to focus in front of the retina, this condition is known as | Myopia |
| A four year old child is brought to you for their first pair of glasses. The right eye is turned in noticeably. This condition is known as | Esotropia |
| The area of the retina capable of perceiving the greatest amount of detail is? | Macula |
| The average cornea has a refractive power of approximately | 42-45 diopters |
| The layer of the cornea which is highly regenerative is? | the Epitheluim |
| Night vision is chiefly a function of the | RODS |
| the term used to indicate "double vision" is | Diplopia |
| When there is loss of vision without any apparent disease of the eye, It Is known as? | amblyopia |
| A refractive error in which rays of light d not come to a single point of focus is called | Astigmatism |
| The condition in which the crystalline lens gradually loses it transparency with consequent loss of visual acuity is known as? | Catract |
| A tendency of one eye to deviate upwards is | Esophoria |
| A condition in which the refractive error of one eye signficicantly differs from that of the other and were both eyes have the same sign? | Anisometropia |
| If the eyelashes rub on the back surface of the lenses, the fitter should? | Increase vertex distance |
| The wearer has previously broken , crooked nose causing glasses to sit to far left . What should be done to fix problem? | Move both right and left pads to the left |
| The temples on a frame do not open the same amount, one has a greater temple spread than the other. When this happens, the lens that will be closer to the eye will be the lens | On the same side as the more widely spread temple |
| How should the bifocal height be positioned for a child? | at the center of the pupil |
| One prism Diopter | Focuses parallel rays of light at one meter |
| What is the smallest blank size for a 50mm round eye size frame if the lens must be decentered? | 56 mm |
| The failure of a refracting surface or lens to bring all rays from an object point toward a desired image point is called? | Aberration |
| The horizontal distance in millimeter between vertical and tangents to the apex of the rim groove of a lens opening on the temporal and nasal sides of the spectacle is called? | "A" measurement |
| The dioptric adjustment of the crystalline lens of the eye to attain maximal sharpness of retinal imagery for and object of regard | Accommodation |
| Clarity or clearness? | Acuity |
| A general term for any error of refraction in the eye | Ametropia |
| Unequal size of images formed on the two retinas, when symptomatic , may be corrected by prescribed iseikonic lenses | Anisekonia |
| Unequal refractive errors in two eyes | Anisometropia |
| Opposite refractive errors in the two eyes; one plus ; one minus | Antimetropia |
| The principal meridian of an astigmatic lens, which contains the least curvature in the meridian, which is 90 degrees from the meridian containing the full cylinder power. | Axis |
| The vertical distance in millimeters between superior and inferior horizontal tangents? | "B" measurement |
| Have two concave surfaces? | Bioconcave |
| Having to convex surfaces? | Bioconvex |
| The horizontal linear measurement in millimeters between the reflexes of the visual axes of the wearers two eyes? | Binocular PD |
| Inflammation of the eyelids? | Blepharitis |
| A lens that functions as a combination of a spherical lens and cylindrical lens | Compound lens |
| Ophthalmic lens in which one of the principal meridians has zero refraction power? | Cylinder Lens |
| The act if decentering an ophthalmic lens; usually expressed in millimeter. Decentration maybe employed to achieve desired prismatic effects. | Decentration |
| In optical science the scattering of the light by irregular reflection at a surface, or within an optical medium | Diffusion |
| A positive or negative optical unit measurement? | Diopter |
| Distance between lenses | DBL |
| The curve in a spectacle front that follows the contours of the human face as viewed from above; also called head curve, parabolic curve | Face form |
| The ration of the velocity of the light in air to the velocity in a given medium. the ration expresses the ability of a lens material to refract or bend a ray of light of given wavelength. | Index of refraction |
| A crescent shaped structure? | Meniscus |
| Optical Dexter (right eye) | OD |
| The direction of any meridian other than 90 degrees (vertical) and 180 degrees (horizontal) | Obilque |
| Optical sinister (left eye) | OS |
| Oculi Uterquie (latin for both eyes ) | OU |
| Impairment of vision due to advancing years after age 40 | Presbyopia |
| The change in direction of light as it passes obliquely from one medium to another of different optical density or refractive index? | refraction |
| A lens that has the same refractive power in all meridians? | Spherical lens |
| A lens to correct astigmatic ametropia with one or both surfaces having different power meridians of least and greatest curvature located at right angles to each other | Toric |
| The total power of a lens expressed in dioptric units? | Vertex Distance |
| an imaginary line connecting the geometric center of a pair of lenses the 180 line | x-Axis |
| An imaginary line perpendicular to the X-Axis the 90 degree meridian | Y-Axis |
Created by:
emme13