Retinal correspondence

RETINAL CORRESPONDENCEOPTOM FASLU MUHAMMED

RETINAL CORRESPONDENCE

Retinal elements of the two eyes that share a common subjective visual direction are called corresponding retinal points

CYCLOPEAN EYE

LAW OF SENSORY CORRESPONDENCE

The existence of corresponding retinal elements with their common relative subjective visual directions is the essence of binocular vision

SENSORY FUSION

The unification of visual excitations from corresponding retinal images into a single visual percept, a single visual image

An individual cannot see double with corresponding retinal elements.

Single vision is the hallmark of retinal correspondence.

Double vision is the hallmark of retinal disparity

For sensory fusion to occur, the images not only must be located on corresponding retinal areas but also must be sufficiently similar in size, brightness, and sharpness.

Unequal images are a severe sensory obstacle to fusion.

Obstacles to fusion may become important factors in the etiology of strabismus.

Differences in color and contours may lead to retinal rivalry

MOTOR FUSION The ability to align the eyes in such a manner that

sensory fusion can be maintained

motor fusion is the exclusive function of the extra foveal retinal periphery

RETINAL RIVALRY When dissimilar contours are presented to

corresponding retinal areas, fusion becomes impossible.

Instead, retinal rivalry may be observed. This phenomenon, also termed binocular

rivalry

Simultaneous excitation of corresponding retinal areas by dissimilar stimuli does not permit fusion;

but since such excitations are localized in the same visual direction and since two objects localized in the same place give rise to conflict and confusion, one or the other is temporarily suppressed

HOROPTER Aguilonius

Helmhotz

PHYSIOLOGIC DIPLOPIA On EH – single

Not in EH – double

FIXATION DISPARITY

STEREOPSIS

the relative ordering of visual objects in depth, that is, in the third dimension

The greater the depth effect, the greater the horizontal disparity

MONOCULAR CUE

Non-stereo depth cue One eye can judge its Patients with binocular vision defect still can feel

the depth perception

MONOCULAR CUEOcclusion near objects block the

view of distant objectsApparent size if two objects are

actually the same size, but one appears smaller, then the small one is farther away than the larger relative size

Motion parallax and Relative velocity near objects appear move faster than distant objects

Light and Shading distance and colour

Overlapping contour*

RELATIVE SIZE

MOTION PARALLAX

MOTION PARALLAX Translocation of the head Cause the images of near objects to move

opposite the head The images of far objects to move with the

head Assuming the fixation point is at an

intermediate distance

LIGHT AND SHADE

OVER-LAPPING CONTOURS

MONOCULAR CUEPerspective parallel lines

converge in the distanceAerial perspectiveGeometric perspective Texture becomes finer with

distanceColour change colour becomes

more blue with distance Atmospheric effect

Haze objects become fuzzy in the distance

Accommodation our brain knows how hard our eyes are working to focus

AERIAL PERSPECTIVE

GEOMETRIC PERSPECTIVE

REFRACTIVE AGE

DEPTH PERCEPTION

Monocular cues Non stereoscopic binocular clues Stereopsis

WHY FOVEA/PERIPHERY DIFFERENCES Range of disparities in natural scenes. Fovea - high depth acuity. Periphery - provides coarse information about

where to make convergence eye movements.

MISTAKE IN BSV• Motoric

– Squint• Refractive

– Aniseikonia• Eye Sensoric

– Amblyopia• Optical problems

– Visual illusion• Brain Perception

– Experience– Monocular cues– Visual illusion

VISUAL ILLUSION

VISUAL ILLUSION

VISUAL ILLUSION

VISUAL ILLUSION

VISUAL ILLUSION

SIZE ILLUSION

BEUCHET CHAIR

BEUCHET CHAIR

AMES ROOM

AMES ROOM

VISUAL ILLUSION: SHADOW EFFECT

VISUAL ILLUSION: SHADOW EFFECT

VISUAL ILLUSION: JUST 2D

VISUAL ILLUSION: MOVING TEXTURE

VISUAL ILLUSION: COLOUR

VISUAL ILLUSION: GRID ILLUSION

VISUAL ILLUSION: BLEEPED-UP

VISUAL ILLUSION: THE CONFUSE

VISUAL ILLUSION: FLOOR PAINTING

VISUAL ILLUSION: SINGLE PHOTO

VISUAL ILLUSION: SINGLE PHOTO

VISUAL ILLUSION: BISTABLE



VISUAL ILLUSION: MIRAGE

A superior mirage occurs when the air below the line of sight is colder than the air above it.

A inferior mirage occurs when the air below the line of sight is hotter and has lower index bias than the air above it.

MIRAGE: HOT HAZE

Heat shimmer refers to the inferior mirage experienced when viewing objects through a layer of heated air

VISUAL ILLUSION: MOONBOW

VISUAL ILLUSION: HALOA sun dog (or sundog), mock sunor phantom sun, scientific name parhelion (plural parhelia), is an atmospheric phenomenon that creates bright spots of light in the sky, often on a luminous ring or halo on either side of the sun.

Sundogs may appear as a colored patch of light to the left or right of the sun, 22° distant and at the same distance above the horizon as the sun, and in ice halos.

They can be seen anywhere in the world during any season, but they are not always obvious or bright.

Sundogs are best seen and are most conspicuous when the sun is low.

SUNSET GREEN FLASH

The optical phenomenon known as the green flash can occur at sunrise or sunset, and it’s most often seen over low, unobstructed horizons such as the ocean.

SUN PILLAR

A Sun pillar is an atmospheric phenomenon caused when high-altitude ice crystals reflect the rising or setting Sun’s reddened light.

SCINTILLATION OR GRID ILLUSION

VISUAL ILLUSION: OPTIC1. Thermal Inversion

The Titanic was sailing from Gulf Stream waters into the frigid Labrador Current, where the air column was cooling from the bottom up, creating a thermal inversion: layers of cold air below layers of warmer air.

Extraordinarily high air pressure kept the air free of fog.

VISUAL ILLUSION: OPTIC2. Superior Mirage

A thermal inversion refracts light abnormally and can create a superior mirage: Objects appear higher (and therefore nearer) than they actually are, before a false horizon.

The area between the false horizon and the true one may appear as haze.

VISUAL ILLUSION: OPTIC3. Iceberg Camouflage

The Californian’s radio operator warned the Titanic of ice. But the moonless night provided little contrast, and a calm sea masked the line between the true and false horizons, camouflaging the iceberg.

A Titanic lookout sounded the alarm when the berg was about a mile away—too late.

VISUAL ILLUSION: OPTIC

4. Mistaken Identity• Shortly before the collision,

the Titanic sailed into the Californian’s view—but it appeared too near and small to be the great ocean liner.

• Californian captain Stanley Lord knew the Titanic was the only other ship in the area with a radio, and so concluded this ship did not have one.

VISUAL ILLUSION: OPTIC5. Morse Lamp• Lord said he repeatedly

had someone signal the ship by Morse lamp “and she did not take the slightest notice of it.”

• The Titanic, now in trouble, signaled the Californian by Morse lamp, also to no avail.

• The abnormally stratified air was distorting and disrupting the signals.

VISUAL ILLUSION: OPTIC

6. Distress Rockets Ignored• The Titanic fired distress

rockets some 600 feet into the air—but they appeared to be much lower relative to the ship.

• Those aboard the Californian, unsure of what they saw, ignored the signals.

• When the Titanic sank, at 2:20 a.m. April 15, they thought the ship might be simply sailing away.

CONFLICTING CUES: ONLY BINOCULAR Random Dot Stereograms

CONFLICTING CUES: ONLY BINOCULAR Random Dot Stereograms

3D ABILITY: 3D MOVIE

The archetypal 3D glasses, with modern red and cyan color filters, similar to the red/green and red/blue lenses used to view early anaglyph films.


Resembling sunglasses, polarized glasses are now the standard for theatrical releases and theme park attractions.


A pair of LCD shutter glasses used to view XpanD 3D films. The thick frames conceal the electronics and batteries

3D VISION ABILITY

3D VISION ABILITY

3D VISION ABILITY

3D VISION ABILITY

3D VISION ABILITY

3D VISION ABILITY

3D VISION ABILITY

3D VISION ABILITY

3D VISION ABILITY

3D VISION ABILITY

3D VISION ABILITY

3D VISION ABILITY

3D VISION ABILITY

3D VISION ABILITY

3D VISION: GAME

THE HIDDEN TIGER

SHAPE OF LIFE: PAREIDOLIA

LOCH NESS MONSTER

LOCH NESS MONSTER

BEYOND THE LECTURE

I have seen with my own eyes! So now… What do you think? Seeing doesn’t mean believing Think again!

Thank you

Healthcare

Retinal correspondence