midterm exam Flashcards
What is the term for the part of the retina where we get our sharpest vision?
The macula.
Which of these accurately describes astigmatism?
Light focuses at several different points.
What occurs in esotropia?
One or both eyes turn inward.
Which of these conditions causes severe impairment of peripheral vision?
Glaucoma.
When you’re fitting people for glasses, you’ll measure their pupillary distance. What is this?
The distance from the center of one pupil to the center of the other pupil.
Which of these frame styles will flatter the features of a person with a base-down triangular face shape?
Frames that are wider at the top than at the bottom.
Which of these is the typical range for a pantoscopic tilt?
5 to 15 degrees.
What is the focal length of a -3.00 lens?
-.333 meters.
Which of these eyes has mixed astigmatism?
+1.25 -2.25 x 80.
Which of these bifocal segments is a good choice for a pilot who needs to have good close vision through both the top and bottom of a lens?
A double D segment.
What clear, glistening tissue covers the sclera?
The conjunctiva.
Which of these problems occurs in macular degeneration?
Poor central vision.
Which of these very common frame materials is hypoallergenic?
Titanium.
What will you use a distometer for?
Measuring vertex.
What do you do when you transpose a prescription?
You change it from a negative cylinder form to a positive cylinder form.
Using a lens clock, you find that the front surface of a lens reads -2.25. The back surface reads -1.50. What is the power of the lens?
-3.75.
What is the range of the visible light spectrum?
380 to 760 nm.
David wears bifocals. His right-eye prescription is -2.00 -1.25 X 90 with an add of +2.50. What is the total power of this lens in the add portion?
+0.50
Take a look at the following prescription:
OD: +2.50 +0.75 x 093
OS: -3.50 +1.25 x 180
What numbers do you get when you transpose this prescription?
OD: +3.25 -0.75 x 003 and OS: -2.25 -1.25 x 090
Which of these is an accurate statement about pantoscopic tilt?
Each additional two degrees of pantoscopic tilt will move the optical center of a lens down one millimeter.
The total power of a lens is +1.50. The back surface measurement is -6.5. What is the front surface measurement?
+8.00.
Which of the following materials is excellent for children’s sports frames because it doesn’t shatter easily?
Polycarbonate.
How does light behave when it moves from one medium to another?
Light bends toward the normal when it moves from a rarer to a denser medium.
Correct
Which list below contains three refractive errors?
Astigmatism, myopia, and hyperopia.
Which of these is an accurate statement about progressive lenses?
Adaptation to progressive lenses is difficult if the monocular PDs are not measured correctly.
