REFRACTED ERRORS

Question 1

AXIAL LENGTH

Answer 1

The eye is a compound lens system that refracts light. It is the power of this lens system and the axial length of the eye that determine the refractive error of the eye.

Question 2

A 1 mm change in axial length results in how many diopters difference in the power of the eye?

Answer 2

I dont know

Question 3

Emmetropia

Answer 3

The emmetropic eye is a normal eye in which all the rays of light from a distant object are focused sharply on the retina. NO refractive error is present. There is no need for corrective distance lenses. PLANO Sph

Question 4

Ametropia

Answer 4

The plus power of the eye can be excessive or inadequate, possibly resulting in decreased vision. In both instances, the power can be corrected. This is done so by changing the total plus power of the eye with lenses so that it IS at an adequate level.

Question 5

Myopia

Answer 5

Also called near-sightedness, this is a condition where parallel light rays come to a focus at a point just in front of the retina

Question 6

Hyperopia

Answer 6

I dont know

Question 7

Minus lenses and all the characteristics

Answer 7

Also, when an image is viewed through a minus lens, the image will appear to move in the same direction as the lens when it is moved side to side or up and down. This is referred to as “with motion”. Minus lenses diverge rays of light. Light going through the thinnest part of the lens (the optical center) is NOT refracted. This is because it is perpendicular to the lens surface. Everywhere else, the angle of incidence is not 90 degrees and will therefore be refracted according to Snell’s law.

Question 8

Plus lenses and all their characteristics

Answer 8

AGAINST MOTION

An image viewed through a plus lens appears magnified. OTC reading glasses are plus lenses, thus people call them “magnifiers”. When an image is viewed through a plus lens, the image will appear to move against the motion of the lens as it is moved side to side or up and down. This is referred to as “against motion”. Plus lenses converge rays of light. Light rays going through the thickest part of the lens (the optical center) are NOT refracted.

Question 9

Which way is light bent through a prism?

Answer 9

Light is always bent towards the base of a prism. If a convex lens is 2 prisms placed base to base, the light will converge inward towards the base of each prism.

Question 10

The speed at which waves travel is called

Answer 10

Velocity

Question 11

The Color in the visible spectrum with the shortest wavelength is

Answer 11

Violet

Question 12

The separation of white light into the spectral component is

Answer 12

Dispersion

Question 13

In reflection the angle of incidence is equal to

Answer 13

The angle of reflection

Question 14

What does the Index of refraction tell you?

Answer 14

It tells us the amount by which light slows in a given medium

Question 15

The power of a lens is measured in

Answer 15

Diopters

Question 16

Which part of the eye has the greatest refractive power

Answer 16

Cornea

Question 17

Distance from the center of a lens to the focal point is called

Answer 17

Focal Length

Question 18

When going from a higher IR to a lower IR light will be reflected towards the normal?

Answer 18

False

Question 19

If the focal length is 16 inches what is the power of the lens

Answer 19

2.50 D

Question 20

What is the focal length in cm if the power of a lens in 5.00 D

Answer 20

100/5= 20 cm

Question 21

A larger radius of a curvature has a steeper curve

Answer 21

False

Question 22

The higher the power of a lens is the longer the focal length will be

Answer 22

False- SHORTER

Question 23

Light intensity is measured by

Answer 23

foot candles

Question 24

The bending of light rays is known as

Answer 24

Refraction

Question 25

The power of a lens is determined by its

Answer 25

Refracted index and Curvature

Question 26

A convex lens will

Answer 26

Magnify ++

Question 27

A myopic eye is too long and required a

Answer 27

Minus lense

Question 28

The overall power of the eye is

Answer 28

PLUS +++

Question 29

Convergence is achieved with a

Answer 29

PLUS Lens

Question 30

Formula for velocity of light is

Answer 30

wavelength X frequency

Question 31

Index of refraction is an expression of

Answer 31

Optical density

Question 32

What kind of lens has a virtual focal point?

Answer 32

CONCAVE

Question 33

What causes light to bend when entering a new medium

Answer 33

Change in speed

Question 34

When a plus lens is moved the image will move

Answer 34

against motion

Question 35

When a minus lense is moved the image will

Answer 35

it will move along

Question 36

The speed of light increases or decreases depending on

Answer 36

Index of refraction

Question 37

The refracted index of air is

Answer 37

1.00

Question 38

Snell law is the

Answer 38

Law of refraction

Question 39

In reflection the angle incidence is equal to the

Answer 39

Angle of reflection

Question 40

The hyperopeic eye has ( ) plus power

Answer 40

too little

Question 41

The ray that is entering a medium is the

Answer 41

Incident ray

Question 43

A minus lense is Apex to Apex?

Answer 43

true

Question 45

A concave will diververge light rays

A convex will diverge light rays?

Answer 45

true

False