ABO Practice Questions with correct Answers

What controls the amt of light entering the eye - Answer- Iris Meniscus, equiconcave and flat concave are types of: - Answer- Minus lenses What is the term used to describe the eye's tendency to turn from its normal position? - Answer- Phoria What kind of lens has one convex and one concave surface? - Answer- Meniscus What material has the most favorable optical properties? - Answer- Crown glass What is the best lens treatment to reduce water and road surface glare? - Answer- Polarized The hard resin material used in plastic lenses is known as: - Answer- CR-39 Aphakia is: - Answer- the absence of a lens The cornea's index of refraction is: - Answer- 1.37 Which term is used to describe the outward inclination of the bottom of a framed lens? - Answer- Retroscopic A monocular PD is given as one number. T or F? - Answer- False You are preparing to block a set of lenses for edging. The frame in the tray measures 55-16 with ED of 60 and B of 56. The work order specifies the Pd as 63/60 with a vertical height of 31. How do you move the lens on your protractor grid if the lens is an OS? - Answer- a)4mm right, 3mm up b)3mm left, 4mm up c)4mm left, 3mm up d)2mm right, 4mm up e)3mm right, 1mm up What would be the near only correction for the following Rx? -10.00 +2.50 X 60 -11.00 +3.00 X 150 Add +2.75 - Answer- The answer is in minus cylinder. The question is in plus cylinder. (-10.00 +2.50) -2.50 X 60 = -7.50 -2.50 X (60 + 90)(-11.00 +3.00) -3.00 X (150 - 90) = -8.00 -3.00 X 60 In order to find the reading Rx, we add the bifocal add power algebraically to the sphere powers. (-7.50 +2.75) -2.50 X 150 = -4.75 -2.50 X 150(-8.00 +2.75) -3.00 X 60 = -5.25 -3.00 X 60 The best method of achieving a uniform sunglass color in a glass lens would be to use: - Answer- d)a vacuum coating Inducing prism by decentration: - Answer- a)can be done on any lens b)is limited by equipment only c)is limited by lens size d)can only be done on a single vision lens e)is limited by lens size, design, and power Which of the Seidel aberrations can be caused by too much pantoscopic tilt? - Answer- b)oblique astigmatism Oblique astigmatism is also called marginal astigmatism, or radial astigmatism, and is an aberration that occurs when light rays pass through the lens at an angle. It forms two line images instead of a single point which causes double vision or blurriness. The best way to eliminate as much oblique astigmatism as possible is to get the best base curve for each lens power. This is one of the reasons behind Corrected Curve Theory. Today's Wave Front technology is a better way of accomplishing this. Too much pantoscopic tilt can add oblique astigmatism instead of reduce it. The OC should be dropped 1mm for each 2° of pantoscopic tilt. Which tint takes the longest to soak into a plastic lens? - Answer- b)blue What cylinder powers can be off axis by 3° and still pass inspection? 1. Those 0.75 D and under 2. Those 1.00 D and under 3. Those 1.25 D and under 4. Those 1.50 D and under 5. Those 1.75 D and under - Answer- e)all but 5 The tolerance for axis according to ANSI is 3° for powers of 1.00 D to 1.50 D. Above 1.50 D it is 2°. However, everything below 1.00 D can be off 3° as well because they can be off more than 3°! If the base curve is +4.00, what could likely be the lens power? - Answer- a)-4.00 b)+4.00 c)+2.00 d)+6.00 e)-6.00 An LCM Optyl temple piece: - Answer- a)is adjusted the same as any Optyl temple b)needs high heat for adjustment c)needs minimal heat for adjustment d)is completely clear with no metal reinforcements e)will return to its original shape when reheated How many degrees can a 1.50 D cylinder be off axis and still pass ANSI? - Answer- idk which of the following frame materials is the lightest? - Answer- a)Proprionate b)Optyl c)carbon d)Polymide e)Cellulose Acetate Your patient wants trifocals in a frame measuring: A = 52, B = 32, Ed = 53, DBL = 19. You measure his lower pupil margin at 19. What is the seg drop? - Answer- a)on line b)1mm above c)2mm above d)3mm above e)1mm below The Rx +1.00 -2.00 X 90 is an example of: - Answer- a)mixed astigmatism b)compound myopic astigmatism c)compound hyperopic astigmatism