Week 7

Question 1

Focus L onto the R

What is the function of the lens?

Answer 1

Focuses light onto the retina

Question 2

Eyeball too L or Powerful C

What causes myopia?

Answer 2

Eyeball too long or powerful cornea

Question 3

Age related loss of L F

What is presbyopia?

Answer 3

Age-related loss of lens flexibility

Question 4

Changes D

How does the pupil adapt to light?

Answer 4

Changes diameter (2-8 mm)

Question 5

Increases DoF, Reduces Ab and G

Benefits of a smaller pupil?

Answer 5

Increases depth of field, reduces aberration and glare

Question 6

Provides most R P

Role of the cornea?

Answer 6

Provides most refractive power.

Question 7

Changes S to focus on N/F objects

How does the lens accommodate?

Answer 7

Changes shape to focus on near/far objects

Question 8

Carries I from the R to the B

Function of the optic nerve?

Answer 8

Carries information from the retina to the brain

Question 9

Focus L onto the R to estimate S strength

Purpose of the ophthalmoscope?

Answer 9

Focuses light on the retina to estimate spectacle strength

Question 10

Ph, Ho, Am, Bi, Gan C

Main cell types in the retina?

Answer 10

Photoreceptors, horizontal, amacrine, bipolar, and ganglion cells

Question 11

Ro, Co, Hor, Bip

Which retinal cells do not exhibit action potentials?

Answer 11

Rods, cones, horizontals, and bipolars

Question 12

Change AP rate and send S to the B

What is the function of ganglion cells?

Answer 12

They change action potential rate and send signals to the brain

Question 13

To minimize Ref/Sca and be closer to the B S

Why are photoreceptors adjacent to the pigment epithelium?

Answer 13

To minimize reflectance/scatter and be closer to the blood supply

Question 14

Determines the minimum Se of two points before they are P as Se

What is the pointspread function?

Answer 14

It determines the minimum separation of two points before they are perceived as separate

Question 15

Rec are Sat and can no longer detect L

What happens when photopigment is bleached?

Answer 15

Receptors are saturated and can no longer detect light

Question 16

Low L vision using Ro, High Sens, Low Acu

What is scotopic vision?

Answer 16

Low light vision using rods, high sensitivity, low acuity

Question 17

High Lum vision using Con, Low sens, High Acu

What is photopic vision?

Answer 17

High luminance vision using cones, low sensitivity, high acuity

Question 18

Gradual increase in V S in the D over ~20 mins

What is dark adaptation?

Answer 18

Gradual increase in visual sensitivity in the dark over ~20 minutes

Question 19

Process mediated by Hor C that enhances E detection

What is lateral inhibition?

Answer 19

A process mediated by horizontal cells that enhances edge detection

Question 20

Concept of 3 opponent channels : R-G, Y-B, B-W

What is colour opponency?

Answer 20

The concept of three opponent channels: Red-Green, Yellow-Blue, Black-White

Question 21

Colours appear S despite C in the WL of L

What is colour constancy?

Answer 21

Colours appear the same despite changes in the wavelength of light

Question 22

Mono, Dich, Anom Trich

What are the types of defective colour vision?

(Think of colour blind mode on games [tritanope])

Answer 22

Monochromats, dichromats (protanopes, deuteranopes, tritanopes), and anomalous trichromats

Question 23

Where O N splits and information is R to the V C

What is the role of the optic chiasm?

Answer 23

It is where the optic nerve splits and information is relayed to the visual cortex