Anatomy & Physio of the Eye

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  1. 3 chambers of the eye
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  2. The refractive power of the average cornea is = to about __ diopters while that of the crystalline lens is __ diopters. The combo of these 2 results in a total refractive power of a full __ diopters
    • 43.00;
    • 17.00;
    • 60.00
  3. the sequence of structures through which light passes through the eye
    • 1. cornea
    • 2. aqueous humor
    • 3. pupil
    • 4. crystalline lens
    • 5. vitreous humor
    • 6. retina
  4. non-transparent structures of the eyeImage Upload
  5. provides nutrients to the retina and other parts of the eye
  6. provides protection and helps maintain the eye's shape
    sclera (whites)
  7. regulates the amount of light entering the eye by changing the size of the pupil
  8. optic nerve
    carries impulses from the retina to the brain
  9. layers of the cornea
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  10. corneal layer that is highly regnerative
  11. Overall, the cornea is about __ thick at its center with the stroma comprising __ % of the total thickness
    0.5 mm; 90
  12. spot on the retina that contains no rods or cones and creates a natural physiological blind spot
    optic disc (at the head of the optic nerve)
  13. The optic nerve takes a route that includes a crossover area known as the __ and ends at the __
    optic chiasma; occipital lobe

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  14. The greatest density of __ are found in the fovea
  15. responsible for perceiving the greatest amount of visual detail
    fovea centralis
  16. Radiating from the fovea, the population of __ gradually decreases while the population of __ increases.
    cones; rods
  17. Cones function in __
    • day vision
    • detail
    • color
  18. Rods function in __
    • night vision
    • peripheral vision
    • black and white
  19. some diseases of the retina
    • macular degeneration
    • retinis pigmentosa
    • diabetic retinopathy
  20. index of refraction of transparent structures
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  21. the transparent, colorless mass of soft, gelatinous material filling the eyeball behind the lens
    vitreous humor
  22. the clear watery fluid that fills the anterior and posterior chambers within the front part of the eye. It is produced continuously by the ciliary body
    aqueous humor
  23. fibrous tunic
    • outer layer
    • protective coat of the eye
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  24. vascular tunic
    • middle layer
    • also known as the vueal tract
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  25. neural tunic
    • inner layer
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  26. The crystalline lens is a transparent lens located __
    behind the iris & the pupil
  27. The crystalline lens is flexible & has about __ diopters of power
  28. functions to change the focal distance of the eye so that it can focus on objects at various distances
    Crystalline Lens

    - allows a sharp image of the object of interest to be formed on the retina
  29. During __, the eye adjusts for viewing objects at various distances. This is accomplished by the __ changing shape through the action of the __
    • accommodation;
    • crystalline lens;
    • ciliary muscle
  30. occurs during accomodation
    • 1. The ciliary muscle relaxes allowing for thickening of the crystalline lens.
    • 2. The eyes converge.
    • 3. The pupil constrict.
  31. __ is continuously produced by the ciliary processes and this rate of production must be balanced by __
    • Aqueous humor (or fluid);
    • an equal rate of aqueous humor drainage
  32. For a distance PD less than 62 mm, you should subtract __ for near.
    2 mm
  33. For a distance PD between 62 and 66, you should subtract __ for near.
    3 mm
  34. For a distance PD more than 66 mm, you should subtract __ for near.
    4 mm
  35. As a general "rule-of-thumb," eyes with wider distance PD's will __ for reading than those with narrower distance PD's.
    converge more
  36. When the 6 eye muscles are working properly the 2 eyes can work together, enabling the brain to __
    fuse the 2 images it receives into one
  37. If one or more of the 6 eye muscles is weaker or stronger than normal, __
    the eyes may not be able to move in perfect unison. The resulting imbalance can make fusion difficult or even impossible, resulting in diplopia (double vision).
  38. Very often an element in the prescription called __ will be prescribed to help alleviate diplopia (double vision).
  39. The 2 general conditions resulting from an imbalance of the extraocular muscles are __ and __
    Phorias; Tropias
  40. a tendency of the right eye to turn outward
    right exophoria
  41. a definite turning inward of the left eye
    left esotropia
  42. a tendency of the right eye to turn upward
    right hyperphoria
  43. a definite turning downward of the left eye
    left hypotropia
  44. muscular imbalance of the eye
  45. a functional eye that for some reason becomes a non-seeing eye
  46. causes of amblyopia
    • strabismus
    • anisometropia
    • antimetropia
  47. The diopter power between the right and left eyes is greater than 2.00 diopters causing the image sizes to vary by more than 5% (aniseikonia). In this condition, both the eyes are plus or minus.
  48. Cause images with such a size difference that they cannot be fused together in the brain. When the brain perceives diplopia or unequal images, the brain eventually ignore the signal from one eyes and that eye becomes amblyopic.
  49. common corrections for strabismus and amblyopia
    correcting the refractive error, patching the good eye, vision therapy, surgery and prescribed prism
  50. a fluctuation of the eye or eyes and is truly a muscular condition. caused by a nerve or multiple nerve malfunctions and is often accompanied by extreme photophobia (sensitivity to light)
  51. Light comes to focus directly on the retina when accommodation is relaxed. No corrective lenses are needed for distance viewing.
  52. when an eye has an error and parallel light does not focus on the retina. 2 types: refractive where the cornea is too strong or too weak and axial where the eye is too big or too small
  53. Light comes to focus in front of the retina, requiring corrective lenses.
  54. Light comes to focus behind the retina, often requiring corrective lenses
  55. strongest refracting lens of the eye and is the most common cause of a refractive error
    the cornea
  56. When the central curve of the cornea is the same all around, a __ lens will correct the refractive error.
  57. When the center of the cornea has more than one curvature, __ exists and a __ lens will be needed to correct the condition.
    astigmatism; toric or compound
  58. If the astigmatism is __, meaning that the principal meridians are 90 degrees away from each other, spectacles with __ lenses will correct the problem.
    regular; cylinder or toric
  59. If the corneal astigmatism is __, then spectacles will probably not correct the patient's problem.
  60. In regular astigmatism, light __
    comes to 2 points of focus
  61. In __ astigmatism, one of the points of focus always fall on the retina.
  62. One point comes to focus on the retina and one point comes to focus in front of the retina.
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    simple myopic astigmatism
  63. One point comes to focus on the retina and one point comes to focus behind the retina.
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    simple hyperopic astigmatism
  64. Both points of light come to focus in front of the retina
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    compound myopic astigmatism
  65. Both points of light come to focus behind the retina
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    compound hyperopic astigmatism
  66. One point of light comes to focus in front of the retina, while the other comes to focus behind the retina
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    mixed astigmatism
Card Set:
Anatomy & Physio of the Eye
2017-08-16 20:20:27

ABO part 1
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