Lecture 6 - Vision 1

Question 1

Refraction

Answer 1

Bending of light waves at an angulated surface of a transparent material

Light striking a perpendicular surface continues on through without bending

Question 2

What does the degree of refraction depend on?

Answer 2

• Ratio of the 2 refractive indices of the 2 transparent media
• Degree of angulation between the interface and the entering wave front of the light waves

Question 3

Refractive Index

Answer 3

Ratio of the velocity of light in air to the velocity of light traveling in the substance

RI of air = 1.00

Question 4

Refractive Power

Answer 4

Measure of how much a lens bends light waves; measured in diopters

1 diopter = 1 meter divided by the focal length of a lens

Question 5

Focal Point

Answer 5

Point through which all parallel rays of light will pass after passing through each part of the lens

Question 6

Focal Length

Answer 6

Distance from the center of the lens to the focal point

Question 7

Important Notes on the Eye

Answer 7

• Object as projected on the retina will be reversed and inverted
• Iris of the eye controls the amount of light entering the eye from darkness to light conditions
• Depth of focus of the lens increases as the pupillary diameter decreases

Question 8

Emmetropia

Answer 8

Refers to the normal eye with regard to depth of focus; parallel light rays from distant objects are in sharp focus on the retina when the ciliary muscle is completely relaxed; all distant objects can be seen clearly

Question 9

Hyperopia

Answer 9

Farsightedness; usually due to an eyeball that is too short or, occasionally, a lens system that is too weak; all distant objects can be seen clearly

Question 10

Myopia

Answer 10

Nearsightedness; when ciliary muscle is completely relaxed, light rays coming from distant objects are focused in front of the retina; usually due to too long of an eyeball

Question 11

Visual Acuity

Answer 11

Measure of the resolving power of the eye

Question 12

What is aqueous humor formed by?

Answer 12

Ciliary processes; ciliary apparatus consists of 2 opposing layers of epithelial cells with a space between them; Na+ ions are actively transported into this space and are accompanied by Cl- and bicarbonate ions; the ions draw water (via osmosis) into the space and the aqueous solution is then passed into the anterior chamber

Question 13

Flow of Fluid in the Eye

Answer 13

Fluid flows from the anterior chamber into the canal of Schlemm and from there into aqueous veins in the sclera

Question 14

What is normal intraocular pressure?

Answer 14

15 mm Hg

Question 15

What photosensitive pigment do rods use?

Answer 15

Rhodopsin

Question 16

What photosensitive pigment do cones use?

Answer 16

Three different color pigments (blue, green, red); these are transmembrane conjugated proteins

Question 17

Outer Segment of Photoreceptor

Answer 17

Site of light-sensitive photochemicals

Question 18

Inner Segment of Photoreceptor

Answer 18

Contains organelles, especially mitochondria

Question 19

Synaptic Body of Photoreceptor

Answer 19

Connects with horizontal and bipolar cells

Question 20

There are a few things we may wanna draw through that I couldn’t make into flashcards; not sure how important it is though

Question 21

What is the total refractive power of the normal eye?

Answer 21

59 diopters