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;
20 Cards in this Set
- Front
- Back
|
Axis Meridian |
The meridian of least power of a cylinder or spherocylinder lens. |
|
|
Axis of a cylinder |
An imaginary reference line used to specify cylinder orientation |
|
|
Base curve |
The front surface curve of a lens of which all other curves are based off of. |
|
|
Back base curve |
The weaker back surface curve of a minus cylinder lens. |
|
|
Neutralize |
To find the power of a lens. |
|
|
Cylinder |
A lens having a refractive power in one meridian only and used in the correction of astigmatism. |
|
|
Focal point |
The point at which rays of light passing through a lens are brought to focus. |
|
|
Minus cylinder form lens |
A lens with two curves on the back, expressed in minus form. |
|
|
Nominal power |
An estimate of total lens power, calculated as the sum of front and back surface curves. |
|
|
Optical center |
The point which light passes through a lens undeviated. |
|
|
Plus cylinder form lens |
A lens that the cylinder is expressed in a positive number. |
|
|
Power cross |
A schematic representation of the two major meridians of a lens surface. |
|
|
Power meridian |
The meridian of maximum power of a cylinder or spherocylinder lens. |
|
|
Refractive power |
The ability of a lens to bend light. |
|
|
Real image |
The focal point of a plus power lens. |
|
|
Virtual image |
The focal point of a minus power lens. |
|
|
Diopter |
The unit of refraction power of a lens. |
|
|
Convex curve |
The front outward curve of a lens, and sometimes the back curve of an extremely high plus lens. |
|
|
Concave curve |
The back inward curve of a lens, and sometimes the front curve in extremely high minus lens. |
|
|
Meniscus lens |
A lens having both convex and concave curves, most common lens. |
