ABO EXAM PRACTICE PART TWO QUESTIONS AND ANSWERS

a pair of eye with a distance P.D. =68mm, converge for a reading an average of about - Answer- 3 to 4 mm if the pupillary distance is measured while the patient is focusing on a point 30 inches in front of the eyes, the P.D. measured is known as the - Answer- intermediate P.D. the instrument that opticians commonly use to measure the vertex distance is called a - Answer- distometer if the long edge of an adjustable nose pad digs into a persons nose, which angle should be altered? - Answer- splay when using the boxing method, the "B" measurement is the - Answer- vertical measurement of a boxed lens the type of bridge on a plastic frame designed to rest entirely on the nose pads is the - Answer- keyhole selecting a new frame involves several aspects. The most obvious is - Answer- the frame should center the pupils in the lenses, how the frame shape relates to the face shape, and the correct frame will have minimal decentration a semi-rimless mounting consists of - Answer- lens bars (with bridge) connecting end pieces and temples to amount a lens in a nylon suspension type frame, it would be necessary to - Answer- grove the lens cellulose acetate is a commonly used frame material because - Answer- hypoallergenic in fitting aphakic lenses, always consider - Answer- a frame with adjustable nose pads, a frame allowing the least amount of reflection in wearing, and a frame that offers at least A&B difference if the lenses of a patient wearing -15.00 spheres are brought closer to his/her eye, what, if any, effect will this have on the effective power? - Answer- increases minus power effect what base curve would you believe good to use on the RX: O.U. +3.00 +0.50 x 90 - Answer- +8.00 base the refractive anomaly indicated by the RX : +1.75-2.75 x90 is? - Answer- mixed astigmatism if a prescription warrants vertex compensation, but no refraction vertex is given, what is the best course of action? - Answer- call the refracting doctors office the best impact resistant -10.00 D lens is a - Answer- polycarbonate lens a -4.75 DS lens decentered 4 mm produces a - Answer- 1.9 prism slab-off is normally ground on the lens that has what in the 90th meridian? - Answer- weaker plus if a prism can deviate a ray of light 2cm at a distance of 2m, what would its power be? - Answer- 1 diopter a lens which reads +3.00 -2.00 x 90 is decentered 6 mm too much. How much prismatic effect will the wearer experience? - Answer- 0.6 prism a plus lens moved downward from the primary position results in - Answer- base down prism effect which of the following bifocals can be ground in plus cylinder form? - Answer- ultex the base curve of a bifocal lens is the curve on the surface where the what is located? - Answer- segment it is a "generally" accepted procedure to fit the top of the trifocal segment to the - Answer- bottom edge of the pupil when fitting progressive power lenses, certain critical measurements are taken. One of the most important is the: - Answer- monocular pupillary measurement an advantage of a round segment bifocal over the executive type is - Answer- it is less conspicuous when a pair of spectacles is tilted so that the bottom of the lenses are closer to the face that the top, it is called - Answer- pantoscopic tilt the plier best used for adjustment of rocking pads in the - Answer- half round lens calipers are used to measure lenses for - Answer- thickness the chapel plier is used when - Answer- cutting off the ends of glass screws how long must a patients records be kept on impact resistance? - Answer- 3 years to widen the distance between pads of a frame or mounting, bend the pad arms - Answer- outward to widen the distance between the pads of a frame or mounting, bend the pad arms - Answer- inward the specifications for the food and drug administration drop-ball test are - Answer- 15.9mm steel ball, dropped 127cm the cylinder axis tolerance for a 0.75D cylinder (ANSI Z80.1-2005) for Prescription Ophthalmic Lenses is - Answer- 5 degrees ANSI Z80.1 2005 recommendation for Impact-Resistant Prescription Ophthalmic Glass Lenses allows a tolerance for refractive power sphere of - Answer- 00.00-6.65D +-0.13D above 6.50D+-2.00% the prism power tolerance for a mounted pair of eyeglasses in the vertical meridian (ANSI Z80.1 2005