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THE EYES

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.

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THE EYES

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  1. THE EYES

  2. 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.

  3. Cornea Iris Retina Pupil OPTIC NERVE Lens ANATOMY AND PHYSIOLOGY OF THE HUMAN EYE

  4. Components of the Eye • Cornea - Transparent tissue located over the front of the eye. • Iris - Round, pigmented membrane surrounding the pupil. • Pupil - Opening in the center of the iris. • NOTE: Pupil size.

  5. Components of the Eye (cont.) • Lens - Transparent, biconvex membrane behind the pupil. • Retina - Thin multi-layered membrane which covers most of the posterior compartment of the eye.

  6. Jacob’s Membrane • Cones - Allow you to identify color. Seven million with a 1: 1 ratio. Sharp visual acuity and color sense. • Rods - Allow you identify the outlines of shapes. 120 million with a 10,000: 1 ratio. More sensitive to light at night.

  7. Detailed View of Rod & Cone Cells

  8. CONES

  9. RODS

  10. Retinal Blind Spots • Day - In the area of the optic disk caused by an absence of photoreceptor cells (rods and cones). 5-7.5 degree field. • Night - Central viewing axis (fovea). Absence of rod cells. Inability of cone cells to functions under low ambient light conditions. 5-10 degree field.

  11. BLIND SPOT

  12. Types of Vision • Photopic vision • Mesopic vision • Scotopic vision

  13. Photopic vision Photopic Vision • Day light or bright light • Central vision • Color sense and sharp images • Better visual acuity LISTEN TO MIKE, WHILE YOU STUDY THE PICTURE.

  14. Photopic Vision Photopic 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.

  15. Mesopic Vision • Dawn and dusk lighting & full moonlight • Parafoveal regions (rods and cones) • Decreased visual acuity and color vision

  16. Scotopic Vision • Night vision (partial moon & stars) • Peripheral vision (rods only) • Acuity degraded 20/200 (color blind) • Off center viewing to compensate blind spot

  17. Limitations of Night Vision • Depth perception • Visual acuity • Blind spot • Night adaptation • Color vision

  18. DEPTH PERCEPTION

  19. VISUAL ACUITY, NIGHT

  20. VISUAL ACUITY, DAY

  21. COLORVISION Photopic Mesopic Scotopic

  22. NIGHT ADAPTATION • 30 to 45 min. for complete adaptation. • Can take up to 3 to 5 hours if exposed to the glare of snow, water, or sun.

  23. Photosensitivity of the eye. Bleaching effect of rods and cones. Effect of red light on rods. Nutrition. DARK ADAPTATION FACTORS

  24. Sunglasses (NV-15) Adjust cockpit lights Turn off exterior light Close one eye Avoid brightly lit areas. Nutrition Supplemental oxygen PROTECT NIGHT VISION

  25. FLIGHT HAZARDS • Solar glare • Bird strike • Laser

  26. SOLAR GLARE

  27. BIRD STRIKE

  28. LASERS • LASERS - light amplification by a stimulated emission of radiation. • Very narrow beam of light • Widen with distance • Severe injuries, burns of the eyes

  29. Laser injury

  30. SELF-IMPOSED STRESSES • Drugs • Exhaustion • Alcohol • Tobacco • Hypoglycemia (Health)

  31. SCANNING TECHNIQUES • Stop-turn-stop-turn technique. • Ten degree circular overlap. • Off-center viewing.

  32. SCANNING STOP-TURN-STOP-TURN

  33. OFF-CENTER VIEWING View object by looking 10 degree above, below, or to either side.

  34. ASTIGMATISM

  35. Visual Deficiencies Myopia (nearsightedness) Hyperopia (farsightedness)

  36. CUES TO DEPTH PERCEPTION • Binocular cues • Monocular cues

  37. BINOCULAR CUES • Valuable only when object is close. • Each eye has a slightly different view.

  38. MONOCULAR CUES • Object seen as one picture. • Are derived from experience

  39. DISQUALIFYING MEDICAL/SURGICAL PROCEDURES • Radial Kerototomy • Photocoagulation • Laser iridotomy

  40. RADIAL KERATOTOMY • Creates spoke like incisions on the cornea. • Permanent disqualification for aviators.

  41. PHOTOCOAGULATION • Removal of protein by the controlled use of an intense beam of light. • Treatment of retinal vessels or intraoculat masses.

  42. LASER IRIDOTOMY • Incision of the iris • Creation of an artificial pupil

  43. SUMMARY

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