Chapter 1

Question 1

Is defined as the process by which the crystalline lens varies its focal length in response to changes in the vergence of incident light.

Answer 1

Accommodation

Question 2

Image formed by the optical system of the eye.

Answer 2

Optical image

Question 3

Image formed on the retina, which may be either sharply focused or blurred.

Answer 3

Retinal image

Question 4

Which part of the eye contributes more than two thirds of the refraction of the eye?

Answer 4

Cornea

Question 5

What part of the eye accounts for about 1/3 of the refraction of the eye?

Answer 5

Crystalline lens

Question 6

What part of the eye is responsible for the changing the power of the lens during accommodation?

Answer 6

Ciliary muscle

Question 7

What are the three types of fibers in ciliary muscle?

Answer 7

1. Longitudinal fibers
2. Radial fibers
3. Circular fibers

Question 8

Light travels from which direction?

Answer 8

Left to right

Question 9

Divergent rays of light are considered?

Answer 9

Negative

Question 10

Convergent rays of light are considered?

Answer 10

Positive

Question 11

The extent to which the image may be located in front of or behind the retina and still appear to be clear is referred to as?

Answer 11

Depth of focus

Question 12

The extent to which the visual acuity chart may be moved toward or away from the patient is referred to as?

Answer 12

Depth of field

Question 13

Defined as the resolving power of the eye, or the ability to see two separate objects as separate.

Answer 13

Visual acuity

Question 14

In _______ eye with accommodation relaxed, parallel rays of light converge to a sharp focus on the retina.

Answer 14

Emmetropia / emmetropic

Question 15

Condition in which the accommodation relaxed, parallel rays of light converge to a focus in front of the retina.

Answer 15

Myopia

Question 16

The far point of accommodation for myopic eye is defined as the farthest object for which an image point is focused on the retina, is always located at a _____ distance in _____ of the retina.

Answer 16

Finite; front

Question 17

The near point of accommodation of the a myopic eye is defined as the nearest object point in which an image is focused on the _____ and is always located in ____ of the eye.

Answer 17

Retina; front

Question 18

Myopia can occur in two extreme forms.

Answer 18

• Axial length of the eye can be normal & focal length of the optical system is longer than normal.
• Axial length of the eye can be longer than normal & the focal length of the optical system is normal.

Question 19

Myopia cmay be corrected with _____ lens.

Answer 19

Diverging / negative

Question 20

Once an individual begins to become myopic (typically occurs during childhood) the amount of myopia tends to increase gradually with time. What kind of myopia is this?

Answer 20

Progressive myopia

Question 21

This is a result of prolonged accommodation in which the ciliary muscle is thought to increase in tonicity to the point where it fails to fully relax when distance vision is attempted.

Answer 21

Ciliary spasm

Question 22

In the beginning stages of myopia, the individual may complain that distance vision blurs following prolonged near work but it clears after a few minutes.

Answer 22

Pseudomyopia

Question 23

The amount of myopia that is reversible (pseudomyopia) is probably no more than ____ D.

Answer 23

1.00 D

Question 24

Having difficulty seeing at night especially when the person is driving.

Answer 24

Night myopia

Question 25

The amount of night myopia is usually no more than ____ to ____ D.

Answer 25

0.50 D to 1.00 D

Question 26

It is a condition in which rays of light converge to a focus behind the retina.

Answer 26

Hyperope

Question 27

What are the two extreme forms of hyperope?

Answer 27

- Axial length of the eye can be normal & the focal length of the optical system longer than normal. - Axial length of the eye can be shorter than normal & the focal length of the optical system is normal.

Question 28

The far point of accommodation for an uncorrected hyperopic eye is an imaginary point located ____ the retina.

Answer 28

Behind

Question 29

The near point of accommodation for a hyperopic eye may be either a ____ object point located in _____ of the eye or an imaginary point located ____ the eye.

Answer 29

Real; front; behind

Question 30

Hyperopia is corrected by means of _____ lens

Answer 30

Converging / Convergent / Positive

Question 31

Hyperopia is compensated by the tonicity of the ciliary muscle is called?

Answer 31

Latent hyperopia

Question 32

Type of hyperopia that cannot be compensated for by accommodation?

Answer 32

Absolute hyperopia

Question 33

Type of hyperopia that can be overcome or compensated for by accommodation?

Answer 33

Facultative hyperopia

Question 34

A refractive condition in which the eye's optical system is incapable of forming point image for a point object.

Answer 34

Astigmatism

Question 35

Most corneas are more steeply curved in the vertical meridian than in the horizontal meridian, causing the vergence of light to be greater in the vertical than in horizontal meridian.

Answer 35

With the rule astigmatism

Question 36

When the vergence of light is greater in horizontal meridian than in vertical meridian is called?

Answer 36

Against the rule astigmatism

Question 37

A refracting surface having the same radius of curvature in different meridians is called

Answer 37

Spherical surface

Question 38

A refracting surface having different radii of curvature in different meridians is called

Answer 38

Toric surface

Question 39

With accommodation relaxed, if one focal line is located on the retina and the other is either in front of the retina or behind the retina, what type of astigmatism?

Answer 39

Simple astigmatism

Question 40

With accommodation relaxed, if both focal lines are either in front or back of the retina, the condition is called?

Answer 40

Compound astigmatism

Question 41

With accommodation relaxed, one focal line is located in front of the retina and other behind the retina is called?

Answer 41

Mixed astigmatism

Question 42

What type of lens you must give to a simple astigmatic patient?

Answer 42

Cylindrical lens

Question 43

What type of lens you must give to a compound astigmatic patient?

Answer 43

Toric lens

Question 44

This occurs when the near point of accommodation has receded to the point that is difficult or impossible to accommodate sufficiently for reading or other close work.

Answer 44

Presbyopia

Question 45

There is a significant difference in the spherical refractive errors for two eyes of 1.00 D and more

Answer 45

Anisometropia

Question 46

The refractive error of both eyes has same amount.

Answer 46

Isometropia

Question 47

A person is myopic in one eye and hyperopic in the other

Answer 47

Antimetropia

Question 48

It is a condition in which lowered visual acuity exists even with best corrective lenses

Answer 48

Amblyopia