Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
25 Cards in this Set
- Front
- Back
|
Visual Axis What does it mean? |
Light enters the eye from viewed object to the fovia. |
|
|
Emmetropia |
No refractive errors. Light focus on fovea |
|
|
Ametropia |
Has refractive errors. Doesn’t allow images to focus on retina |
|
|
Myopia |
Near sighted. Long eye Images focus in front on retina |
|
|
Hyperopia |
Far sighted Short eye Images focus behind fovea |
|
|
With the rule vs against the rule vs Oblique |
With the rule Axis @ 90’ Against the rule Axis @ 180’ Oblique near 45’ or 135’ |
|
|
Presbyopia |
Difficult to focus Loss of accommodation Ur old |
|
|
When does refraction Occur? |
When the speed of light is traveling and it increases or decreases depending on the density of the medium. |
|
|
Concave lens vs convex Lens |
Concave lens- thin, goes inward for minis Convex lens-thick, goes outward for plus |
|
|
Spherical lenses |
Have the same curvature in all meridians, single focus, Corrects myopia hyperopia n presbyopia with NO astigmatisms |
|
|
Cylindrical lenses |
Have 2 optical surfaces, curves and flat located 90’ apart Curves side reflects light and flat line has no power Corrects simple myopic and simple hyperopic |
|
|
Spherocylindrical lens |
Has 2 different powers in 2 meridians Corrects compound myopia, compound hyperopia and mixed astigmatisms |
|
|
Light is refracted Through the optical _1__ of the lens. It’s is the thinnest part of the __2___ lens and the thickness part of the _3___ lens. |
1 Center 2 Minus 3 Plus |
|
|
What is the First step in Lensometry? |
Focus the eye piece counter clock wise |
|
|
How do you know if a lens is spherical or cylindrical? |
Thine mires are sphere power Thick mires are cylindrical power Spherical lens have BOTH mires mires into focus at the same time. Only have one power all around. Cylindrical won’t have both mires focus. One focused one blurry |
|
|
Single visions glasses |
Corrects near sighted or far sighted Only one |
|
|
Bifocals |
Lens incorporate 2 different prescription |
|
|
Trifocals |
Incorporate 3 different prescriptions |
|
|
Progressive additions Lenses (PAL’s) |
Have no lines in the lens, corrects distance,near and intermediate. |
|
|
Near vision What is the distance? |
14 to 16 inches from eye |
|
|
Intermediate vision Distance? |
24 to 30 inches away |
|
|
Far vision Distance? |
36 inches to infinity |
|
|
CAP And FAL |
Cap-Closer Add Plus FAL-Far Add Less |
|
|
How do you determine the ADD power on a progressive lens? |
Read laser etched numbers on temporal side of lens. |
|
|
What are some problems with progressive lens? |
Are no lines on lens to help you guide Will not be accurate measurements on lensometry |
