ABO Practical exam 2023 with 100% correct answers

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