Corneal Refractive Surgery

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Corneal Refractive Surgery
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Lasik Defined

• Lamellar refractive surgery that combine the use
  of a microkeratome to make a hinged corneal flap,
  and the exemer laser to reshape the exposed
  stromal bed.
• as the year of 2000,lasik is the most common
  ocular surgical procedure done in the US

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Your laser vision experience

• Anatomy
• Refractive errors
• Type of refractive surgery.

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The Eye The body camera
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Conea

• The clear tiusse at the front of the eye.
• The cornea is responsible for up to 2\3 of the
  focusing of the eye.

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Conea

• The adult cornea is only about 1/2 millimeter
  thick and is comprised of 5 layers  epithelium,
  Bowman's membrane, stroma, Descemet's membrane
  and the endothelium. 

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Lens

• The clear ceystalline lens which is responsible
  for the remaining focusing power of the eye.
• The lens dose the fine focusing for the eye

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Retina

• The tissue at the back of the eye often referred
  to a the film of the eye.

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Refractive Errors

• Myopia (Nearsightedness)
• Hyperopia (Farsightedness)
• Astigmatism
• Presbyopia

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Myopia (Nearsightedness)

• Nearsightedness is a vision condition in which
  near objects are seen clearly, but distant
  objects do not come into proper focus.

• Nearsightedness occurs if your eyeball is too
  long or the cornea has too much curvature, so the
  light entering your eye is focused in front of
  the retina rather than directly on the retina.

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Hyperopia (Farsightedness)

• Farsightedness is a vision condition in which
  distant objects are usually seen clearly, but
  close ones do not come into proper focus.

• Farsightedness occurs if your eyeball is too
  short or the cornea has too little curvature, so
  light entering your eye is focused behind the
  retina rather than directly on the retina.

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Astigmatism

• Astigmatism is a vision condition that occurs
  when the front surface of your eye, the cornea,
  is slightly irregular in shape.

• This irregular shape prevents light from focusing
  properly on the back of your eye, the retina .As
  a result, your vision may be blurred at all
  distances.

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Presbyopia

• Presbyopia is a vision condition in which the
  crystalline lens of your eye loses its
  flexibility, which makes it difficult for you to
  focus on close objects. 

• Presbyopia usually becomes noticeable in the
  early to mid-40s. Presbyopia tends to be
  progressive, but it is not a disease, it is
  simply a natural part of the aging process. Some
  signs of presbyopia 

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Type of refractive surgery

• LASIK
• LASEK
• EPI_LASIK
• PRK

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Pre - operative Examination

• Ocular health
• Visual acuity
• Refraction
• Corneal thickness
• Corneal topography

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- Ocular health
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Visual Acuity

• Snellen Visual Acuity Chart

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Refraction
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Corneal thickness
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Corneal topography Placido Ring
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Corneal topography Scheimpflug 
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Zernikes
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Visual Aberrations
Halos
Coma
Optimized Vision
Spherical aberration
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Range of Possible Correction

• Myopia up to 12 D
• Hyperopia up to 6 D
• Astigmatism up to 6 D

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Calculation
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LASIK
Video
LASEKPRK
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Eye Trakcer
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Thermal Effect
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Rotation_Balance
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Fluence_Level
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Mohammad Tahseen

• Thank you