Optics and the Eye. The Visible Spectrum Some similarities between the eye and a camera.

Slides:



Advertisements
Similar presentations
The Eye SNC2D.
Advertisements

Extrinsic Eye Muscles Figure 15.3a, b.
Perception Chapter 2 The physics of light: What we see is a small part of the electromagnetic spectrum call visible light -- refer to overhead. Physical.
Chapter 2: The Beginnings of Perception. Figure 2-1 p22.
 How do our eyes respond to light?  Why do our eyes have two different sets of receptors – rods and cones?
Sensory Physiology Vision, Hearing, and Orientation.
The eye – curved cornea – lens – retina – fovea – optic disk Using Light.
Parts of the Eye - Pupil.
Imaging Science FundamentalsChester F. Carlson Center for Imaging Science The Human Visual System The Eye.
BOVINE EYE DISSECTION INTRO – Spring 10. Can humans or non-human animals see in the dark?
Textbook sections 27-1 – 27-3 Physics 1161: PreLecture 25 Lenses and your EYE Ciliary Muscles.
 Cornea: ◦ Tissue that forms a transparent, curved structure in front of the eye ◦ Refracts light before it enters the eye  Retina: ◦ A layer of cells.
Physics 1161: Lecture 19 Lenses and your EYE
The Human Visual System The Eye. Anatomy of the Human Eye Cornea Pupil Iris Sclera Retina Optic Nerve Lens.
The Human Eye and Vision The structure of the eye –Iris –Cornea –Lens Focusing –Cornea –Accommodation The Retina –Photoreceptors –Processing time –Sensitivity.
Physics 1161: Lecture 23 Lenses and your EYE
Pg  The Eyeball The Eyeball  Iris: coloured part of the eye that opens and closes to let in more or less light. In the centre you find.
The Eye: Structure & Function
THE HUMAN EYE Lights and Lenses. Explore: How does the eye focus an image? Procedure: -Position yourself so you can clearly see an object across the room.
Vision Our most dominant sense
1 Chapter 5: The Human Eye and Vision - I: Producing the Image Using what we have learned about lenses and cameras to understand how the eye works The.
Physics. PHS 5041 Optics Lenses Lenses are transparent objects with at least one curved surface. Lenses can be: _Convex or converging (***thickest at.
The Human Eye.
The Human Eye and Vision Optics of the eye (lenses, focusing, etc.) Physiology of the eye (detection of light)
Sensation Chapter 5 Myers AP Psychology. Transduction  Conversion of one form of energy into another.  In sensation, the transforming of stimulus energies,
The Human Eye Written for Physics 106 Friday, Nov. 7, 2008 A good web site for learning much about the anatomy of the human eye is :
VISION the sense we rely on most often. Photoreceptors in the eye are sensitive to wavelengths of light energy called the visible spectrum.
A camera. Where is the film with respect to the focal point?
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Human Anatomy & Physiology, Sixth Edition Elaine N. Marieb PowerPoint ® Lecture.
Human Eye  A human eyeball is like a simple camera! Sclera: White part of the eye, outer walls, hard, like a light-tight box. Cornea and crystalline lens.
Vision – our most dominant sense. Vision Purpose of the visual system –transform light energy into an electro-chemical neural response –represent characteristics.
JP© 1 THE EYE JP© 2 sclera pupil iris JP© 3 cornea sclera choroid retina fovea vitreous humour aqueous humour blind spot optic nerve pupil iris.
The Eye and Sight Describe the relationship between the structure of the eye and sight Contrast ways in which light rays are bent by concave and convex.
textbook sections 27-1 – 27-3 Physics 1161: Lecture 19 Lenses and your EYE Ciliary Muscles.
Can humans or non-human animals see in the dark?.
1. What is Vision ? VISION “A process that produces form images of the external world, a description which is useful to the viewer and not cluttered.
Lenses. Diverging and Converging Lenses Double Convex lenses focus light rays to a point on the opposite side of the lens. Double Concave lenses diverge.
The Human Eye. A convex lens is the type of lens found in your eye. The lens takes light rays spreading out from objects and focuses the light, through.
Chapter 9 - The eye $100 $200 $300 $400 $500 $100$100$100 $200 $300 $400 $500 Eye Anatomy Eye Physiology More Parts of the Eye Eye Problems More Vocab.
Spook Fish. Eyes How We See Eye Anatomy Nocturnal Eye.
Psychology 210 Lecture 4 Kevin R Smith. Vision Sensory System –The eye –Exactly what we sense from our environment Perceptual System –The brain –How we.
Chapter 12 Review Light and Vision. Category: The Eye Give the name and function of the eye part indicated by #3 (the thin layer between #1 and #2). Choroid.
Physics 102: Lecture 19, Slide 1 Today’s Lecture will cover textbook sections 23.9, 24.1, 3-4, 6 Physics 102: Lecture 19 Lenses and your EYE Ciliary Muscles.
Phys 102 – Lecture 20 The eye & corrective lenses 1.
The Human Eye and Vision Optics of the eye (lenses, focusing, etc.) Physiology of the eye (detection of light)
Sensory Physiology The Vision Accommodation Blind spot.
Section 12.1 (Part 1) The Human Eye.
Structure of Human Eye: –Eye Muscles, Optic nerve, sclerotic coat –Cornea, iris, pupil,, lens, retina, blind spot –aqueous humour, vitreous humour, ciliary.
Seeing READING ASSIGNMENT Discussion of Gregory’s Article on Visual Illusions – Tues Feb 17 Available in your course pack.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Human Anatomy & Physiology SEVENTH EDITION Elaine N. Marieb Katja Hoehn PowerPoint.
BOVINE EYE DISSECTION INTRO. Can humans or non-human animals see in the dark?
DO NOW. VisionVision Our most dominating sense. Visual Capture.
EYE The eye is an extension of the brain.
Textbook sections 27-1 – 27-3 Physics 1161: Lecture 19 Lenses and your EYE Ciliary Muscles.
P3 Physics Medical applications Section a) The structure of the eye. The structure of the eye is limited to: ■ retina ■ lens ■ cornea ■ pupil /iris.
Vision Our most dominant sense. Our Essential Questions What are the major parts of the eye? How does the eye translate light into neural impulses?
The Eye.
PL3020/FM2101/PL2033 Physiology Vision 1.
The Eye The sensory receptors in your eye detect light energy. The receptors are stimulated by light rays, which enter your eyes after bouncing off objects.
MODULE #13: VISION. Vision Transduction: transformation of stimulus energy (light, sound, smells, etc.) to neural impulses our brains can interpret. Our.
Ishihara test for color blindness
Vision & Hearing.
Physics 102: Lecture 19 Lenses and your EYE Ciliary Muscles 1.
The Eye.
15 P A R T B The Special Senses.
Anthony’s Textbook of Anatomy & Physiology: Chapter 15
Anthony’s Textbook of Anatomy & Physiology: Chapter 15
Unit 7 Light and Vision.
The Human Eye.
LIGHT AND SOUND YEAR 9 SCIENCE
Presentation transcript:

Optics and the Eye

The Visible Spectrum

Some similarities between the eye and a camera

Refraction - the basis of optics Light bends when it goes from one medium to another The amount or bending, or refraction, depends on the angle incidence, and the nature of the two media

Objects-Lens Distance

Optical Power greater the power the closer the image is to the lens

Convex lenses have positive optical power Concave lenses have negative optical power

The precise distance from the lens to the focused image depends on lens power and the distance to the object according to the following equation: P = 1/F = 1/do + 1/di (lensmaker equation) P = lens power F = the focal distance do = the distance to the object di = the distance to the image (all distances are expressed in meters)

Cornea - does most refracting Lens - does fine focussing

Focussing --Accomodation In humans, fine focussing is controlled through changing the shape of the lens.

Accomodation Changing the lens shape is controlled by the ciliary muscles

Average human eye’s power is 60 diopters (cornea and lens together) Focal distance of such optics is 1/60 = m = 16.7 mm Posterior nodal distance of average eye is 16.7 mm - good fit!

Near and Far Points Near point - closest distance that an object can still be kept in focus. –Will change with age Far point –Normally at optical infinity

Astigmatism Target Sometimes a lens can be emmetropic for light waves in one orientation (say, for horizontal lines), but be badly hyperopic or myopic for other orientations (say, vertical lines). Thus, people with astigmatic vision see sharp lines and contours in some orientations, and blurry contours in others. Astigmatism

Someone with an astigmatism in the vertical orientation might see the target such that the horizontal lines are in focus and of high contrast, but as the lines become more vertical they go out of focus, becoming blurry and lower in contrast.

The Human Eyeball

The cells of the RETINA act as transducers. A transducer changes one form of energy into another. The Retina

Membranous discs contain photopigment

Rod Photoreceptors about 120 million per eye only one kind most sensitive to light of about 505 nm approx. 10 times more sensitive than cones used in night/scotopic vision psychophysical & physiological data indicate that rods can respond to a single photon!

Cone Photoreceptors about 8 million per eye 3 kinds, each most sensitive to 440, 530 or 560 nm basis of colour vision approx. 10 times less sensitive than rods used in day/photopic vision

Distribution of Rods & Cones rods are most dense in periphery no rods in the center of the macula cones are most dense in fovea no receptors in blind spot

Eye Movements

One reason we move our eyes is that we have a relatively narrow field of vision and must move our eyes around to sample the visual world extensively. A second reason we move our eyes is that our retinas are not uniformly sensitive. Our retinas have the highest acuity in the region called the fovea. To see something clearly we orient our eyes so that the image will be projected onto the high resolution fovea. Why move our eyes?

Two Main Classes of Eye Movements 1. Conjugate (Version) - Both eyes move to the same degree and in the same direction 2. Vergence - eyes rotate in opposite directions - e.g. inward to look at a close object

Conjugate Eye Movements

Vergence Eye Movements