INSTRUCTION COURSE SLIT LAMP EXAMINATION MP STATE by c4ai9wy

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									INSTRUCTION COURSE

SLIT LAMP EXAMINATION

MP STATE OPHTHALMIC
CONFERENCE
UJJAIN
2008

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Presented by

Dr. Sanjay Shrivastava
Dr. Nikhilesh Trivedi
Dr. Kavita Kumar




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Slit Lamp Examination

The science of examination with a slit
 lamp is called Biomicroscopy as it
 allows in vivo study of living tissues at
 high magnification.




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SLITLAMP EXAMINATION

 •    Permits detailed examination of various
      structures of and posterior segment of eye
 •    Angle of anterior chamber with gonioscope
 •    Measurement of intra ocular pressure
 •    Endothelial cell counts




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SLITLAMP EXAMINATION

•    Photographic representation of every above
     mentioned part of the eye
•     Modern slit lamp and its auxiliary devices
     provide magnified view of parts of eye from
     cornea to retina
•    Measurement of Corneal thickness is also
     possible


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•     Slit lamp is a misnomer
•     In 1925 MAVAS introduced a term bio-
      microscopy defined as examination of the
      living eye by means of the corneal microscope
      and slit lamp.
•     LITTMAN in1950 introduced the rotatory
      magnification charger based on the principle
      of GALILEAN telescope is the forerunner of
      current ZEISS slit lamp .


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PARTS

A. OBSERVTION SYSTEM
B. ILLUMINATION SYSTEM
C. MECHANICAL SYSTEM




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Slit lamp




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The Instrument




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The
Instrument




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Posterior Segment
Examination with +78 D Lens




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  OBSERVATION SYSTEM


       a. Objective lenses -22
        diopters
       b. Eye piece- 10 diopters


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ILLUMINATION SYSTEM

a. Light source
b. Condenser lens system
c. Slit and other diaphgram
d. Filters
e. Projection lens
f. Reflecting mirror/prism2.

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MECHANICAL SYSTEM

A. Joy stick arrangement
B. Up and down arrangement
C. Patient support arrangement
D. Mechanical coupling


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Slit Lamp Examination -Method

•    Prerequisites – Preferably a dark room
     and slit lamp biomicroscope
•    Position – Patient is seated
     comfortably on an adjustable stool,
     with chin resting against chin rest and
     forehead against head rest bar.


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PREPARATION

A. Preliminary examination of eye ball
B. Illumination of room.
C. Preparation and management of
  patients
D. Adjustment of instruments.
E. Stereopsis

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METHODS OF ILLUMINATION

•    Diffuse illumination
•    Sclerotic scatter
•    Direct focal illumination
•    Indirect illumination
•    Retro-illumination
•    Specular reflection
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  SET UP

  1. Angle between microscope and
      illuminating system – 30 deg to 45
      deg.
  2. Slit width - widest.
  3. Filters - diffusing filter
  4. Magnification - low to medium
  5. Illumination – low to high.

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USE

1. Topography of pathological changes.
2. Entire surface of cornea, iris, lens can
   be viewed.
3. Folds of descemets membrane.
4. Corneal scar.
5. Whole configuration of lens.
6. Surface of adult nucleus.
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SCLEROTIC SCATTER
       Also called indirect lateral illumination-it is
       possible by concentrating the beam upon
       the spot at the side of the object it is
       proposed to examine
       Projecting the light upon sclera near the
       limbus,it is easy to examine the limbal
       portion of cornea,and if the incident ray is
       sufficient to induce total internal
       reflection,the whole of cornea including
       the opposite limbus ,is lit up.
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USE

1. Corneal opacities
2. Keratocele
3. Interstitial deposits
4. Perforating scars


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DIRECT FOCAL ILLUMINATION
BASIS OF ALL METHODS.




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SET UP

 Slit beam is regulated until it
  coincides with exact focus of
  microscope.
 Light - narrow slit at an oblique
  angle 30 deg to 45 deg

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THREE SLIT BEAM
EFFECTS

•    OPTICAL SECTION
•    PARALLELOPIPED CORNEAL
     SECTION
•    CONICAL BEAM EFFECT



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 I. OPTICAL SECTION
• Produced by a very narrow slit beam
   focused obliquely.
• It resemble a knife like histological section
   of tissue focused.
   Corneal section uses
• changes in corneal curvature.

• change in corneal thickness.

• depth of corneal pathologies; foreign body
   localization.
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OPTICAL SECTION
                                          Corneal optic section showing;
                                          Tear layer-anterior most bright
                                          zone
                                          Epithelial layer-dark line
                                          immediately behind it.
                                          Bowmen’s membrane-a bright
                                          line.
                                          Stroma-wider granular and
                                          greyer zone.
                                          Descemets membrane and
                                          endothelial layers-posterior
                                          most bright zone.


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II. PARELLOPIPED CORNEA
                              2-3 mm. wide focused slit
                              beam.
                             Because beam traverse
                              cornea obliquely, shape of
                              resulting rectangular block
                              is paralellopiped prism. the
                              ext. and internal surface of
                              which slightly curved owing
                              to anatomic shape of
                              cornea
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USES



1. Pathologies of epithelium and Stroma.
2. Corneal scar or infiltrates. Appear
     brighter.
3. Water clefts have low density so
appear black.

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III. CONICAL BEAM


                                                 Small circular
                                                 beam Used to
                                                 detect the
                                                 aqueous flare




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INDIRECT ILLUMINATION


                                                 Slit beam is
                                                 focused at a
                                                 point just
                                                 behind a area
                                                 to be
                                                 examined.



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SET UP
    Angle between slit beam and
    microscope is 30 deg to 45 deg
   - Beam width - moderate
   - Illumination - low medium or high



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   USES

• Corneal infiltration
• Corneal microcysts
• Corneal vacuoles
• Epithelial cells



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RETROILLUMINATION
                                               Examination of
                                               normal or
                                               pathological
                                               structures in
                                               light reflected
                                               from tissue
                                               situated more
                                               posteriorly

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RETROILLUMINATION




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Direct retro illumination


     Observer in direct pathway of light

     Light is reflected from structures
     so pathology seen against
     illuminated background


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Indirect retro illumination

Observer is right angle to observed
 structures not in line so pathology
 seen against dark non illuminated
 background



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Pathologies can be

1. Obstructive – seen as dark against light
  background eg pigment or blood filled
  vessels
2. Respersive –these scatter light but not
  obstruct completely seen as bright
  against dark background eg epithelial
  edema, precipitates.


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Pathologies can be
3. Refractile – they distort the view of
  junction of illuminated and dark area
  because there refractive index is
  different from surroundings eg
  Vacuoles.




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SPECULAR REFLECTION

•    It is one of the most difficult methods.
     Not possible to use on all kind of slit
     lamps
•    Reflection of light occurs when beam
     of light is incident on an optical surface
     called zone of discontinuity, such
     zones may be found in cornea and
     lens
•    When observer is placed in pathway of
     reflected light a dazzling reflex seen
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 SET UP

• Illuminating and viewing arms each forms and
  angle of about 30 deg to the central
  perpendicular
• Slit beam height of 2 mm and focused onto
  the central corneal endothelium
• Golden sheen with darker lines outline the
  hexagonal endothelial cells
• Magnification of atleast 40X is needs to see
  endothelial pattern

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    USES

•   Surface pathologies scatter the light
    irregularly. therefore create dark area in
    reflex.
•   Using an eye piece reticule endothelial
    cells can be measured and counted
    and also used to study the tear film
    details .
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Oscillating illumination of
Koppe
•    Slit beam is given an oscillatory
     movement by which it is often
     possible to see minute objects and
     filaments especially in the
     aqueous which would otherwise
     escapes detection

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SPECIALISED USES

1. Gonioscopy
2. Fundus examination with focal
     illumination
3. Pachymatery
4. Applanation tonometry
5. Ophthalmodynamometry


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SPECIALISED USES

6. Slit lamp photography
7. As a delivery system for argon ,
  diode and Nd YAG laser
8. Laser interferometry
9. Potential acuity meter test



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                          END OF PART ONE
                                  THANKS
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