NIGHT VISION NIGHT VISION ORIENTATIONORIENTATION
TERMINAL LEARNING OBJECTIVE
Action:Action: Compensate for Visual Compensate for Visual limitations.limitations.
Condtions: While performing as an Condtions: While performing as an aircrew member.aircrew member.
Standard: In accordance with FM 1-Standard: In accordance with FM 1-301,FM 8-2, and TC 1-204.301,FM 8-2, and TC 1-204.
Depth perceptionDepth perception Visual acuityVisual acuity Blind spotBlind spot Night adaptationNight adaptation Color visionColor vision
ENABLING LEARNINGENABLING LEARNINGOBJECTIVEOBJECTIVE
Identify the limitations of night visionIdentify the limitations of night vision
DEPTH PERCEPTIONDEPTH PERCEPTION
VISUAL ACUITY
BLIND SPOT
NIGHT ADAPTATION 30 to 45 min. for complete adaptation.30 to 45 min. for complete adaptation.
Can take up to 3 to 4 hr. if exposed to Can take up to 3 to 4 hr. if exposed to the glare of snow, water, or sun. the glare of snow, water, or sun.
COLORS VISION
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CUES TO DEPTH PERCEPTION
Binocular cues
Monocular cues
BINOCULAR CUES Valuable only when object is close.Valuable only when object is close. Each eye has a slightly different view.Each eye has a slightly different view.
MONOCULAR CUES Object seen as one picture.Object seen as one picture. Are derived from experienceAre derived from experience
GEOMETRIC PERSPECTIVE Linear perceptive.Linear perceptive. Apparent foresighting.Apparent foresighting. Vertical position in the field.Vertical position in the field.
LINEAR PERSPECTIVE
Parallel lines tend to converge.Parallel lines tend to converge.
APPARENT FORESHORTENING
The shape of object appears ellipticalThe shape of object appears elliptical
VERTICAL POSITION IN THE FIELD
Objects appear to be higher on the Objects appear to be higher on the horizon.horizon.
RETINAL IMAGE SIZE Known size of objects.Known size of objects. Increasing of decreasing size of objects.Increasing of decreasing size of objects. Terrestrial association.Terrestrial association. Overlapping contours.Overlapping contours.
KNOWN SIZE OF AN OBJECT
INCREASING OR DECREASING SIZE OF AND OBJECT
Increase in sizeIncrease in size
Decrease in Decrease in sizesize
TERRESTRIAL ASSOCIATION ASSOCIATION
OVERLAPPING CONTOURS
AERIAL PERSPECTIVE Fading colors or shades.Fading colors or shades. Loss of detail of texture.Loss of detail of texture. Position of light source.Position of light source.
FADING COLORS AND SHADES
Objects viewed through haze, fog and Objects viewed through haze, fog and smoke.smoke.
Transmission of light.Transmission of light.
LOSS OF DETAIL OR TEXTURE
POSITION OF LIGHT POSITION OF LIGHT SOURCE AND DIRECTION SOURCE AND DIRECTION
OF SHADOWOF SHADOW
Direction of the shadowDirection of the shadow
MOTION PARALLAX Very important cue.Very important cue. Relative motion.Relative motion. Depends on the distance of the object.Depends on the distance of the object.
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VISUAL ILLUSIONSVISUAL ILLUSIONS
GENERAL INFORMATIONGENERAL INFORMATION
Decrease in visual information.Decrease in visual information. Spatial Disorientation.Spatial Disorientation. The most reliable senses.The most reliable senses. Misinterpretation of what is seen.Misinterpretation of what is seen.
RELATIVE MOTION RELATIVE MOTION ILLUSIONILLUSION
Motion between you and a moving Motion between you and a moving object.object.
Confusing as to who is moving.Confusing as to who is moving.
GROUND LIGHTS GROUND LIGHTS MISINTERPRETATIONMISINTERPRETATION
Misinterpretation of lightsMisinterpretation of lights.
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FALSE VERTICAL ILLUSIONFALSE VERTICAL ILLUSION
Misinterpretation of the horizonMisinterpretation of the horizon
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DEPTH PERCEPTION DEPTH PERCEPTION ILLUSIONILLUSION
Flying over sand, snow, or water.Flying over sand, snow, or water. Flying through haze, smoke, or fog.Flying through haze, smoke, or fog.
STRUCTURAL ILLUSIONSTRUCTURAL ILLUSION
Curved glass, heat waves, rain, snow, Curved glass, heat waves, rain, snow, sleet, or other disturbance.sleet, or other disturbance.
Disturbance/distortion.Disturbance/distortion.
AUTOKINETIC ILLUSIONAUTOKINETIC ILLUSION
Lack of visual references.Lack of visual references. Off center vision and scanning pattern.Off center vision and scanning pattern.
SIZE DISTANCE
False perception of distance from an object False perception of distance from an object on the ground or in the air.on the ground or in the air.
Misinterprets an unfamiliar object’s size to be Misinterprets an unfamiliar object’s size to be the same as an object they are normally the same as an object they are normally accustomed to viewing.accustomed to viewing.
FLICKER VERTIGOFLICKER VERTIGO
Light flickers at a rate of 4 to 20 cycles Light flickers at a rate of 4 to 20 cycles per second.per second.
May cause nausea, vomiting May cause nausea, vomiting convulsions and unconsciousness.convulsions and unconsciousness.
FASCINATION/FIXATION Pilot intent on hitting target.Pilot intent on hitting target. Pilot forgets to fly aircraft.Pilot forgets to fly aircraft. Fly into target or ground.Fly into target or ground.
REVERSIBLE PERSPECTIVE REVERSIBLE PERSPECTIVE ILLUSIONILLUSION
Happens at night.Happens at night. An aircraft flying parallel to yours.An aircraft flying parallel to yours. Corrective actions.Corrective actions. Observe the aircraft lights.Observe the aircraft lights.
ALTERED PLANES OF ALTERED PLANES OF REFERENCESREFERENCES
Approaching a line of clouds or Approaching a line of clouds or mountains.mountains.
Climb in altitude.Climb in altitude. Tend to tilt away from the clouds.Tend to tilt away from the clouds.
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NERVE AGENTSNERVE AGENTS
Effects on night vision.Effects on night vision. Miosis (pupils will not dilate in low Miosis (pupils will not dilate in low
ambient light).ambient light). Minimal to severe symptoms.Minimal to severe symptoms. Recovery may take up to 20 days.Recovery may take up to 20 days. Insidious onset.Insidious onset.
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FLIGHT HAZARDSFLIGHT HAZARDS
Solar glareSolar glare Bird strikeBird strike LaserLaser
SOLAR GLARESOLAR GLARE
BIRD STRIKEBIRD STRIKE
LASERSLASERS
Type of laser. The energy output. Exposure time. Distance from the laser.
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LASERSLASERS
LASERS - light amplification by a LASERS - light amplification by a stimulated emission of radiation.stimulated emission of radiation.
Very narrow beam of light.Very narrow beam of light. Progressively wider with distance.Progressively wider with distance. May cause severe injuries, burning of May cause severe injuries, burning of
the eyes.the eyes.
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MILITARY LASERSMILITARY LASERS
At 1 kilometer, the beam is 1 meter in At 1 kilometer, the beam is 1 meter in diameter. At 2 kilometers the beam is diameter. At 2 kilometers the beam is 2 meters in diameter.2 meters in diameter.
Can irradiate the whole body.Can irradiate the whole body. Can burn clothing.Can burn clothing. Most are not powerful enough to burn.Most are not powerful enough to burn.
THE EYETHE EYE
The eye is very sensitive to light.The eye is very sensitive to light. Concentration of energy focused on the Concentration of energy focused on the
back of the eye can be up to a 100,000 back of the eye can be up to a 100,000 greater than the energy entering the eye.greater than the energy entering the eye.
Energy being absorbed by various Energy being absorbed by various anatomical structures.anatomical structures.
Factors depends on the type of laser, Factors depends on the type of laser, distance, and energy. distance, and energy.
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PROTECTION AGAINST PROTECTION AGAINST LASER INJURYLASER INJURY
Passive measures.Passive measures. Active measures.Active measures.
PASSIVE MEASURESPASSIVE MEASURES
Take cover Protective gear
Protective Goggles B-LPSNVD
Squinting
ACTIVE MEASURESACTIVE MEASURES
Countermeasures (SOP) Maneuvers
Evasive action Scanning Hardened optical systems
Built-in clip on filter Battlefield smoke screens
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BREAKBREAK
SUMMARY
ANATOMY AND PHYSIOLOGY OF THE HUMAN EYE
Retina
Cornea
Iris
Lens
PupilCones
Rods
IDENTIFY THE COMMON VISUAL DEFICIENCIES
Myopia- nearsightedness Hyperopia- farsightedness Presbyopia Astigmatism
ASTIGMATISM
RADICAL KERATOTOMY Creates spoke-like incisions on the cornea. Permanent disqualification for aviators.
VISUAL DEFICIENCIES
Hyperopia (farsightedness)
Myopia (nearsightedness)
PRESBYOPIA As we get older, the
lens loses the elasticity causing an inability to focus on near objects.
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TYPES OF VISION Photopic vision Mesopic vision Scotopic vision
Photopic Photopic visionvision
PHOTOPIC VISION
Day light or bright light Central vision Color sense and sharp Better visual acuity
MESOPIC VISION Dawn and dusk Parafoveal regions
(rods and cones) Decrease visual
acuity
SCOTOPIC VISION
Night vision Peripheral vision (rods only) Acuity degraded 20/200 color blind Off center viewing to compensate blind
spot
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FACTORS AFFECTING DARK ADAPTATION
Photo sensitivity of the eye
Cones- contains chemical
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PROBLEM WITH RED LIGHTNING
No longer use Blue / green lights Focus behind
retina, causing fatigue
Seen at great distance
Creates glare Bleaches color in
map
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PROTECT NIGHT VISION Sunglasses Adjust cockpit light lowest readable
level Turn off exterior light Close on eye Supplemental oxygen
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PROPER VIEWING TECHNIQUE
Scanning Off-center viewing
STOP-TURN-STOP-TURN
SCANNING
OFF-CENTER VIEWING
View object by looking 10 degree above, below, or to either side.
SELF-IMPOSED STRESSES Drugs Exhaustion Alcohol Tobacco Hypoglycemia