Abo Exam Prep Correct Questions & Answers

When discussing thick lenses, the factors which are considered in computing the lens power are: - ANSWER Front curve, back curve, thickness and index Which crown glass bifocal type will have the least chromatic aberration? - ANSWER A "one piece" lens Toric transposition shows: - ANSWER Power in principal meridians Increasing the diameter of a minus power lens always increases its: - ANSWER Weight The optical center of a round segment is located: - ANSWER In the geometric center of the segment The base curve of any multifocal lens is found on the surface containing the: - ANSWER Segment Normal slab-off (bicentric grind) is ground on the lens whose vertical meridian has the: - ANSWER Least plus power The refractive error indicated by the Rx +1.75-2.75x090 is: - ANSWER Mixed astigmatism Tempering a lens by heat treating results in a lens being: - ANSWER More resistant to impact A slab-off lens is for the correction of: - ANSWER Excessive prism imbalance at the reading level Chem-tempering makes a clear glass lens more impact resistant by placing the lens in a potassium nitrate bath. The lens undergoes a process known as: - ANSWER Ion exchange Which wavelengths of light have been indicated as possible contributors