the eyes
DESCRIPTION
THE EYES. TERMINAL LEARNING OBJECTIVE. Action: Eye Physiology Review Conditions: While performing as an aircrew member. Standards : IAW FM 1-301, FM 8-2 and TC 1-204. Cornea. Iris. Retina. Pupil. OPTIC NERVE. Lens. ANATOMY AND PHYSIOLOGY OF THE HUMAN EYE. Components of the Eye. - PowerPoint PPT PresentationTRANSCRIPT
THE EYES
TERMINAL LEARNING OBJECTIVE
Action:Action: Eye Physiology Review Eye Physiology ReviewConditions:Conditions: While performing as an aircrew While performing as an aircrew
member.member.Standards :Standards : IAW FM 1-301, FM 8-2 and TC 1-204. IAW FM 1-301, FM 8-2 and TC 1-204.
ANATOMY AND PHYSIOLOGY OF THE HUMAN EYE
Cornea
Pupil
OPTICNERVE
Retina
Iris
Lens
Components of the EyeCorneaCornea - Transparent tissue located - Transparent tissue located over the front of the eye.over the front of the eye.IrisIris - Round, pigmented membrane - Round, pigmented membrane surrounding the pupil.surrounding the pupil.PupilPupil - Opening in the center of the - Opening in the center of the iris.iris.NOTENOTE: Pupil size.: Pupil size.
Components of the Eye (cont.)
LensLens - Transparent, biconvex - Transparent, biconvex membrane behind the pupil.membrane behind the pupil.
RetinaRetina - Thin multi-layered - Thin multi-layered membrane which covers most of the membrane which covers most of the
posterior compartment of the eye.posterior compartment of the eye.
Jacob’s Membrane
ConesCones - Allow you to identify color. - Allow you to identify color. Seven million with a 1: 1 ratio.Seven million with a 1: 1 ratio. Sharp visual acuity and color sense. Sharp visual acuity and color sense.
RodsRods - Allow you identify the outlines of - Allow you identify the outlines of shapes. 120 million with a 10,000: 1 shapes. 120 million with a 10,000: 1 ratio. More sensitive to light at night.ratio. More sensitive to light at night.
Detailed View of Rod & Cone Cells
CONES
RODS
Retinal Blind SpotsDayDay - In the area of the optic disk caused by an - In the area of the optic disk caused by an absence of photoreceptor cells (rods and cones). absence of photoreceptor cells (rods and cones). 5-7.5 degree field. 5-7.5 degree field.
Night Night - Central viewing axis (fovea).- Central viewing axis (fovea). Absence of rod cells.Absence of rod cells. Inability of cone cells to functions under low Inability of cone cells to functions under low ambient light conditions.ambient light conditions. 5-10 degree field.5-10 degree field.
BLIND SPOT
Types of Vision
Photopic visionPhotopic vision
Mesopic visionMesopic vision
Scotopic visionScotopic vision
Photopic vision Photopic VisionPhotopic Vision
Day light or bright light Central vision Color sense and sharp images Better visual acuity
LISTEN TO MIKE, WHILE YOU STUDY THE PICTURE.
Photopic vision
Photopic VisionPhotopic Vision
Day light or bright light Central vision Color sense and sharp images Better visual acuity
FOR THOSE OF YOU THAT ATTENDED THE BEACH FEST LAST WEEKEND.
Mesopic Vision
Dawn and dusk lighting & full moonlightDawn and dusk lighting & full moonlightParafoveal regionsParafoveal regions (rods and cones)(rods and cones)Decreased visual acuity and color visionDecreased visual acuity and color vision
Scotopic Vision
Night vision (partial moon & stars)Night vision (partial moon & stars)
Peripheral vision (rods only)Peripheral vision (rods only)
Acuity degraded 20/200 Acuity degraded 20/200 (color blind)(color blind)
Off center viewing to compensate Off center viewing to compensate blind spotblind spot
Limitations of Night Vision
Depth perceptionDepth perception Visual acuityVisual acuity Blind spotBlind spot Night adaptationNight adaptation Color visionColor vision
DEPTH PERCEPTION
VISUAL ACUITY, NIGHT
VISUAL ACUITY, DAY
COLOR VISION Photopic Mesopic Scotopic
NIGHT ADAPTATION
30 to 45 min. for complete adaptation.30 to 45 min. for complete adaptation.
Can take up to 3 to 5 hours if exposed Can take up to 3 to 5 hours if exposed to the glare of snow, water, or sun.to the glare of snow, water, or sun.
DARK ADAPTATION FACTORS
Photosensitivity of the eye.Photosensitivity of the eye.
Bleaching effect of rods and cones.Bleaching effect of rods and cones.
Effect of red light on rods.Effect of red light on rods.
Nutrition.Nutrition.
PROTECT NIGHT VISIONSunglasses (NV-Sunglasses (NV-
15)15)Adjust cockpit Adjust cockpit
lightslightsTurn off Turn off
exterior lightexterior lightClose one eyeClose one eye
Avoid brightly Avoid brightly lit areas.lit areas.
NutritionNutritionSupplemental Supplemental
oxygenoxygen
FLIGHT HAZARDS
Solar glareSolar glareBird strikeBird strikeLaserLaser
SOLAR GLARESOLAR GLARE
BIRD STRIKE
LASERSLASERS - light amplification by a LASERS - light amplification by a
stimulated emission of radiation.stimulated emission of radiation.
Very narrow beam of lightVery narrow beam of light
Widen with distanceWiden with distance
Severe injuries, burns of the eyesSevere injuries, burns of the eyes
Laser injury
SELF-IMPOSED STRESSES
DrugsDrugs
ExhaustionExhaustion
AlcoholAlcohol
TobaccoTobacco
Hypoglycemia (Health)Hypoglycemia (Health)
SCANNING TECHNIQUES
Stop-turn-stop-turn technique.Stop-turn-stop-turn technique.
Ten degree circular overlap.Ten degree circular overlap.
Off-center viewing.Off-center viewing.
STOP-TURN-STOP-TURN
SCANNING
View object by looking 10 degree above, below, or to either side.
OFF-CENTER VIEWING
ASTIGMATISM
Visual Deficiencies
Hyperopia (farsightedness)
Myopia (nearsightedness)
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
DISQUALIFYING MEDICAL/SURGICAL
PROCEDURES
Radial KerototomyRadial Kerototomy
PhotocoagulationPhotocoagulation
Laser iridotomyLaser iridotomy
RADIAL KERATOTOMY
Creates spoke like incisions on the cornea.Creates spoke like incisions on the cornea.Permanent disqualification for aviators.Permanent disqualification for aviators.
PHOTOCOAGULATION
Removal of protein by the Removal of protein by the controlled use of an intense beam controlled use of an intense beam of light.of light.
Treatment of retinal vessels or Treatment of retinal vessels or intraoculat masses.intraoculat masses.
LASER IRIDOTOMY
• Incision of the irisIncision of the iris
• Creation of an artificial pupilCreation of an artificial pupil
SUMMARY