Illumination Adaptation

Question 1

What are Scotopic parallel pathways?

Answer 1

Low light systems with rod vision only and higher sensitivity to low colour vision.

Question 2

Define Dark Adaptation.

Answer 2

Light adaptation wherein illumination changes from high to low, which bleaches photopigment.
Chromophore and Opsin must recombine to regain their sensitivity in order to respond to light.

Question 3

Define Light Adaptation.

Answer 3

Illumination changes from low to high and the available photopigment in the retina is bleached in order to reduce sensitivity and adapt to light.

Question 4

How long does it take for rods to adapt to light?

Answer 4

Rod pigment regenerates in 30mins or over in order to regain maximum sensitivity.

Question 5

How long does it take for cones to adapt to light?

Answer 5

Cone pigment regenerates in 6mins to gain maximum sensitivity.

Question 6

What are Mesopic parallel pathways?

Answer 6

Rods and cones act simultaneously with no mutual interaction or overlap with sensitivities.

Question 7

What is Chromatic Adaptation?

Answer 7

When photopigment molecules adapt to an otherwise black and white image.

Question 8

What are Photopic visual pathways?

Answer 8

Parallel pathways with a high light system and cone vision only. Has low absolute sensitivity and good colour vision.

Question 9

What is Duplex nature when describing the retina?

Answer 9

When rods and cones function as independent parallel pathways under different light intensities.

Question 10

What is the best area of sensitivity for the Scotopic visual pathway?

Answer 10

Periphery of the retina where most rods are concentrated.

Question 11

Which visual pathway is the best for night time vision?

Answer 11

Scotopic visual pathway, because they are good for low illumination; cones aren’t sensitive enough for night vision.

Question 12

What is the best area of sensitivity for the Photopic visual pathway?

Answer 12

The central retina where most cones are concentrated.

Question 13

Which visual pathway is the best for daytime vision?

Answer 13

Photopic visual pathway which is good for high illumination; because rod photopigment gets bleached and becomes inoperable during daytime.

Question 14

What are two examples of retinal diseases that affect cones and rods respectively?

Answer 14

Macular Degeneration negatively influences cones.

Retina Pigmentosa negatively influences rods.

Question 15

What is the level of sensitivity for low light ambience?

Answer 15

High sensitivity

Question 16

What is the level of sensitivity for high light ambience?

Answer 16

Low sensitivity

Question 17

What does macular degeneration do to your vision?

Answer 17

Creates a central scotoma or blindspot which is common in elderly.

Question 18

What does retinal pigmentosa do to your vision?

Answer 18

Causes night or complete blindness

Question 19

Which visual alterations help regulate and adjust sensitivity to different illumination and photopigments?

Answer 19

Sunglasses and dilated or constricted pupils which match available photopigments.

Question 20

How do individuals with macular degeneration adapt to their condition?

Answer 20

They avoid the blindspot in order to see clearly.

Question 21

How is macular retinal pigmentosa treated?

Answer 21

Magnification of the central field which makes for a better visual experience.