ABO All Levels Teaching & Review Tool: NAO Flash Cards (#FLASH)
Following are random selections of questions and answers covered in the 485 piece Flash Card set:
What is the best impact resistant – 10.00D lens?
Polycarbonate Lens. Polycarbonate lenses are highly impact resistant and have been used as protective lenses in industrial situations.(7)
A person looking in the primary position lowers the eyes to read. The eyes are now in which position?
Secondary position. The secondary positions of the eyeball means those positions when the eye is directed upward, downward, laterally (out) or medially (in). Since the eyes depress and adduct while converging to read, the eyes move to a secondary position.(3)
A reverse slab-off is molded with base ______ prism in the near portion of the lens.
Down. Reverse slab-off uses base down instead of base up prism. (18)
Which of the following lens aberrations is basically the same in effect as the light dispersing property of prisms?
A. Spherical aberration
B. Chromatic aberration
B. Chromatic aberration. Chromatic aberration is the dispersion of light when passed through a lens.(12)
What is the seg drop (or raise) for a flat top 28 bifocal needing a seg height of 20mm when the B measurement is 42mm?
1mm down. First we need to use ½ of the B measurement as a zero starting point. Here ½ of the B is 21 mm. Since the seg is to be placed at 20 that is 1 mm below the ½ the B measurement. If the seg height is less than ½ the B measurement, the seg must be moved downward.(7)
The progressive addition lens has a progressive zone or corridor where power:
A. Gradually increases
B. Gradually decreases
C. Stays the same
D. Abruptly changes
Gradually increases. The basic construction of a progressive addition lens consists of a distance portion, a near portion, and a corridor between distance and near areas where the power gradually increases.(16)