Presentation is loading. Please wait.

Presentation is loading. Please wait.

Color Vision Dr Taha Sadig Ahmed MBBS. PhD MAANEM.

Published byLynette Hudson Modified over 8 years ago

Similar presentations

Presentation on theme: "Color Vision Dr Taha Sadig Ahmed MBBS. PhD MAANEM."— Presentation transcript:

1 Color Vision Dr Taha Sadig Ahmed MBBS. PhD MAANEM

2

3

4 History of color vision Newton (1704) used a prism to show that sunlight was composed of light with all colors in the rainbow. He defined it as the spectrum.

5 History of color vision Primary colors: 723-647 575-492492-450 Thomas Young 1807: primary colors: when mixed >>> white or any other color

6 Mixing colors

7

8 Photopic vision (CONES) Helmholtz..1860: The three primary colors are perceived by three photoreceptor pigments (with broad absorption curves) White light is produced by mixing three colours

9 Cone wavelength ranges SML Wavelength (nm) Relative absorption 400500600 700

10 Photopic vision (CONES) Cone pigments: three kinds 565 535440

11 Photopic vision Young Helmholtz theory Color vision is subserved by three types of cones, each containing a photoreceptor pigment most sensitive to one primary color 1.Cones (contain red-sensitive pigment) 2.Cones (contain green-sensitive pigment) 3.Cones (contain blue-sensitive pigment) in the fovea centralis

12 Cone wavelength ranges SML Wavelength (nm) Relative absorption 400500600 700

13 Color Blindness Weakness or total blindness in detecting a primary color: Definitions: 1.Trichromats: see the 3 1ry colors 2.Dichromats: blind to one 1ry color 3.Monochromats: have color pigment

14 Color Blindness –cont. Prot …… Red Deuter …. Green Trit …… Blue Anamoly …weakness Protanamoly Deuteranamoly Trichromats Tritanamoly

15 Color Blindness –cont. Anamoly …weakness Anopia …. Total loss Protanopia Deuteranopia Dichromats Tritanopia

16 Trichromatic/dichrom atic color vision

17 Color Blindness –cont. Prevalence: males ………….8% females …. 0.4% Inheritance: sex-linked due abnormal gene in the X chromosome

18

19 Electrophysiology of Vision

20 Light Change in photopigment Metarhodopsin II Activation of transducin Activation of phophodiesterase Decrease IC cyclic GMP Closure of Na channels Hyperpolarization of receptor Action potential in optic nerve fibres

21

22 Photoreception

23

24 Figure 17.15 Bleaching and Regeneration of Visual Pigments

25

26 Electrophysiology of Vision Electric recording in Retinal cells: Bipolar cells: Hyper- & Depolarization Horizental cells: Hyper- & Depolarization Amacrine cells: Depolarizing potential Ganglion cells: Depolarizing potential

27

Download ppt "Color Vision Dr Taha Sadig Ahmed MBBS. PhD MAANEM."

Similar presentations

The Eye. Rods and Cones The eye is made of cells that are called Rods and Cones. Cone cells are coned shaped and Rod cells are rod shaped.

The Eye. Rods and Cones The eye is made of cells that are called Rods and Cones. Cone cells are coned shaped and Rod cells are rod shaped.
Colour Vision Sensitivity & Acuity. Colour Vision Trichromatic theory of colour vision There is only one type of rod and this responds strongly to bluish-

Colour Vision Sensitivity & Acuity. Colour Vision Trichromatic theory of colour vision There is only one type of rod and this responds strongly to bluish-
Box 6.3 Evolutionary Psychology Fig 6.17 Bowerbird Nests.

Box 6.3 Evolutionary Psychology Fig 6.17 Bowerbird Nests.
Chapter 9: Color Vision. Overview of Questions How do we perceive 200 different colors with only three cones? What does someone who is “color-blind” see?

Chapter 9: Color Vision. Overview of Questions How do we perceive 200 different colors with only three cones? What does someone who is “color-blind” see?
1 Color Vision Fundamentals Jeff Rabin, OD, PhD Chief, Visual Function Laboratory Ophthalmology Branch USAF School of Aerospace Medicine.

1 Color Vision Fundamentals Jeff Rabin, OD, PhD Chief, Visual Function Laboratory Ophthalmology Branch USAF School of Aerospace Medicine.
1 Computational Vision CSCI 363, Fall 2012 Lecture 33 Color.

1 Computational Vision CSCI 363, Fall 2012 Lecture 33 Color.
Color Vision Our visual system interprets differences in the wavelength of light as color Rods are color blind, but with the cones we can see different.

Color Vision Our visual system interprets differences in the wavelength of light as color Rods are color blind, but with the cones we can see different.
Wavelength and Color Recall that light is electromagnetic radiation.

Wavelength and Color Recall that light is electromagnetic radiation.
Read article by Land for Thursday Article by Anne Treisman coming up in about two weeks.

Read article by Land for Thursday Article by Anne Treisman coming up in about two weeks.
The Eye Accessory structures or Adnexa 4 layers: 1. Skin – thinnest in the body 2. muscle – orbicularis oculi and levator palpebrae superioris 3. Connective.

The Eye Accessory structures or Adnexa 4 layers: 1. Skin – thinnest in the body 2. muscle – orbicularis oculi and levator palpebrae superioris 3. Connective.
COLOR PERCEPTION Physical and Psychological Properties Theories – Trichromatic Theory – Opponent Process Theory Color Deficiencies Color and Lightness.

COLOR PERCEPTION Physical and Psychological Properties Theories – Trichromatic Theory – Opponent Process Theory Color Deficiencies Color and Lightness.
RGB Models human visual system? Gives an absolute color description? Models color similarity? Linear model? Convenient for color displays?

RGB Models human visual system? Gives an absolute color description? Models color similarity? Linear model? Convenient for color displays?
Chapter 7: Color Vision How do we perceive color?.

Chapter 7: Color Vision How do we perceive color?.
The Retina WALT That the retina contains millions of light sensitive cells That there are two types of light sensitive cell How an action potential is.

The Retina WALT That the retina contains millions of light sensitive cells That there are two types of light sensitive cell How an action potential is.
Physiology of the Retina

Physiology of the Retina
VISION -II Dr.Mohammed Sharique Ahmed Quadri Assistant Professor Department Basic Medical Sciences Faculty of Medicine Almaarefa Colleges 1.

VISION -II Dr.Mohammed Sharique Ahmed Quadri Assistant Professor Department Basic Medical Sciences Faculty of Medicine Almaarefa Colleges 1.
EYES!.

EYES!.
THEORIES OF COLOR VISION

THEORIES OF COLOR VISION
Colour Vision I The retinal basis of colour vision and the inherited colour vision deficiencies Prof. Kathy T. Mullen McGill Vision Research (H4.14) Dept.

Colour Vision I The retinal basis of colour vision and the inherited colour vision deficiencies Prof. Kathy T. Mullen McGill Vision Research (H4.14) Dept.
The Physiology of Vision part 2. Defects of image forming 1- Hyperopia ( farsightedness) : -Is a defect in which the eye-ball is shorter than normal.

The Physiology of Vision part 2. Defects of image forming 1- Hyperopia ( farsightedness) : -Is a defect in which the eye-ball is shorter than normal.

Similar presentations

Ads by Google