Vision Physiology I

Question 1

Light speed _____ when it passes through a transparent substance

Answer 1

Light speed decreases when it passes through a transparent substance

Question 2

REFRACTIVE INDEX (RI) is the ratio of the speed of light in _____ to the speed of light in the _____

Answer 2

REFRACTIVE INDEX (RI) is the ratio of the speed of light in air to the speed of light in the substance

Question 3

žAn angulated interface with different refractive indices causes _____ of light

Answer 3

žAn angulated interface with different refractive indices causes bending of light

Question 4

žThe ____ of _______ increases as the difference in RI increases and the degree of angulation increases

Answer 4

žThe degree of refraction increases as the difference in RI increases and the degree of angulation increases

Question 5

žThe light rays are eventually focused on the _____.

Answer 5

žThe light rays are eventually focused on the retina

Question 6

______ lens causes converging of light rays

Answer 6

convex lens causes converging of light rays

Question 7

In a convex lens, lightrays begin to bend in the _____ and

converge at the ____ _____.

Answer 7

In a convex lens, lightrays begin to bend in the periphery and

converge at the focal point.

Question 8

A _____ lens causes diverging of light rays.

Answer 8

A concave lens causes diverging of light rays.

Question 9

Refractive power is measured in ______

Answer 9

diopters

Question 10

The ______ the diopter, the ______ the lens is able to bend light rays to a simple____ ____.

Answer 10

The greater the diopter, the greater the ens is able to bend light rays to a simple focal point.

Question 11

Which lenses are more likely to be measured in diopters?

Answer 11

Convex lenses

Question 12

What structure of the eye has the greatest refractive power?

Answer 12

the cornea

Question 13

What tells you more about refractive power, the intrinsic refractive power value or the difference between refractive power values?

Answer 13

the difference between refractive power values

Question 14

What is the refractive power of the lens?

Answer 14

20 diopters

Question 15

_______ is the ability of the lens to change shape and become fatter or flatter.

Answer 15

accomodation

Question 16

Why is accomodation necessary?

Answer 16

žto focus the image on the retina

Question 17

On the retina, the image is ____ and ____.

Answer 17

inverted and reversed

Question 18

Relaxed lens is almost _____ in shape

Answer 18

Relaxed lens is almost spherical in shape

Question 19

Lens held in place by _____ _____ that cause the lens to be _____ under normal resting conditions

Answer 19

Lens held in place by suspensory ligaments that cause the lens to be flat under normal resting conditions

Question 20

_____ pulls ligament forward relaxing tension on suspensory ligament making the lens _____

Answer 20

Contraction pulls ligament forward relaxing tension on suspensory ligament making the lens fatter

Question 21

refractive power is greater when ciliary muscles are _____and lens is ____

Answer 21

refractive power is greater when ciliary muscles are contracted and lens is fatter

Question 22

Ciliary muscle controlled by _____ nerve signals

Answer 22

Ciliary muscle controlled by parasympathetic nerve signals

Question 23

When a person looks at an object in the distance, do the ciliary muscles need to contract?

Answer 23

no

Question 24

For near vision, the ciliary muscles ____and the central lens thickness ____to increase its power.

Answer 24

For near vision, the ciliary muscles contract and the central lens thickness increases to increase its power.

Question 25

Presbyopia: ## Footnote žInability to \_\_\_\_\_ \_\_\_\_\_ of the proteins of the lens žLens less \_\_\_\_

Answer 25

Presbyopia: ## Footnote žInability to **_accommodate_** **_žDenaturation_** of the proteins of the lens žLens less **_elastic_**

Question 26

hyperopia ## Footnote accommodate to see ____ objects. eyeball too ____ or refractive power of lens is too \_\_\_\_ the focal point goes ____ \_\_\_\_\_ \_\_\_\_\_

Answer 26

hyperopia ## Footnote accommodate to see **_far_** objects. eyeball too **_short_** or refractive power of lens is too **_small_**. the focal point goes **_beyond the retina_**

Question 27

myopia ## Footnote when eyeball is too _____ or too \_\_\_\_refractive power in the lens. Focal point is ____ \_\_\_\_ \_\_\_\_.

Answer 27

myopia ## Footnote when eyeball is too long or too much refractive power in the lens. Focal point is before the retina.

Question 28

Myopia corrected with _____ lens

Answer 28

Myopia corrected with **_concave_** lens

Question 29

Hyperopia corrected with _____ lens

Answer 29

Hyperopia corrected with **_convex_** lens

Question 30

Astigmatism causes a change in the ____ of light.

Answer 30

angulation

Question 31

Cataracts are characterized by a cloudy or \_\_\_\_\_area of the \_\_\_\_caused by the ____ of lens proteins

Answer 31

Cataracts are characterized by a cloudy or **_opaque_** area of the **_lens_** caused by the **_coagulation_** of lens proteins

Question 32

Visual Acuity ## Footnote \_\_\_\_ or _____ of vision žAbility to perceive ____ \_\_\_\_\_ žDiscern letters or numbers at a given distance (\_\_\_\_ feet)

Answer 32

Visual Acuity ## Footnote **_Clarity_** or **_sharpness_** of vision žAbility to perceive **_small details_** žDiscern letters or numbers at a given distance (**_20_** feet)

Question 33

Motion parallax: a ____ depth cue in which we view objects that are closer to us as moving ____ than objects that are further away from us.

Answer 33

Motion parallax: a **_monocular_** depth cue in which we view objects that are closer to us as moving **_faster_** than objects that are further away from us.

Question 34

stereopsis: you can see with ____ eyes better than you can see with\_\_\_\_

Answer 34

stereopsis: you can see **_two_** eyes better than you can see with **_one_**

Question 35

Intraocular fluid keeps the eyeball ____ and \_\_\_\_\_.

Answer 35

Intraocular fluid keeps the eyeball **_round_** and **_distended_**

Question 36

2 types of intraocular fluid: ## Footnote 1. ______ humor: freely flowing fluid 2. _____ humor: Gelatinous mass with little flow of fluid

Answer 36

2 types of intraocular fluid: ## Footnote 1. **_Aqueous_** humor: freely flowing fluid 2. **_Vitreous_** humor: Gelatinous mass with little flow of fluid

Question 37

Formation of aqueous humor: ## Footnote * Produced by ___ \_\_\_\_\_\_ of the ____ \_\_\_\_ at a rate of 2-3 microliters/min * Aqueous humor formed by ____ \_\_\_\_\_ of ____ \_\_\_\_\_ * Active transport of ___ followed by ____ and \_\_\_\_ * Water follows by \_\_\_\_\_\_\_\_

Answer 37

Formation of aqueous humor: ## Footnote * Produced by **_ciliary processes_** of the **_ciliary body_** at a rate of 2-3 microliters/min * Aqueous humor formed by **_active secretion_** of **_ciliary processes_** * Active transport of **_Na+_** followed by **_Cl-_** and **_HCO3-_** * Water follows by **_osmosis_**

Question 38

Outflow of aqueous humor from the eye: ## Footnote Flow of aqueous humor through the ___ into the _____ \_\_\_\_ of the eye Fluid flows _____ to the ____ and into the angle between the ____ and \_\_\_\_ \_\_\_\_ __ \_\_\_\_\_ and into the _____ \_\_ \_\_\_\_which empties into ______ \_\_\_\_\_.

Answer 38

Outflow of aqueous humor from the eye: ## Footnote Flow of aqueous humor through the **_pupil_** into the **_anterior chamber_** of the eye Fluid flows **_anterior_** to the **_lens_** and into the angle between the **_cornea_** and **_iris_** **_Meshwork of trabeculae_** and into the **_canal of schlemm_** which empties into **_extraocular veins_**

Question 39

Intraocular pressure measures how quickly the flow of ____ \_\_\_\_ enters ____ \_\_ \_\_\_\_.

Answer 39

Intraocular pressure measures how quickly the flow of **_aqueous humor_** enters **_canal of schlemm_**

Question 40

Intraocular pressure is žnormally \_\_mmHg with a range of 12-20 mmHg

Answer 40

Intraocular pressure is žnormally **_15_** mmHg with a range of 12-20 mmHg