Overview of Phaco - PowerPoint PPT Presentation

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Overview of Phaco

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Difficult in cases of filtering surgery e. Maximum ATR TEMPORAL INCISION BETWEEN 8 ... Soft cataract/ posterior subcapsular ... should be small, ... – PowerPoint PPT presentation

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Title: Overview of Phaco


1
Overview of Phaco
  • Dr. Anil Kulkarni, M.S.
  • Miraj

2
Phacodynamics
  • Common Terms
  • USG power
  • Irrigation
  • Aspiration/ Flow
  • Vacuum

3
ACOUSTIC VIBRATOR
  • Two Types
  • Magneto-restrictive-
  • Piezoelectric electrical energy is used to
    reorient piezoelectric crystal which in turn is
    translated in to linear movement.

4
ULTRASONIC POWER
  • Vibration of tip Energy release
  • Jackhammer effect
  • Cavitation
  • when tip retreats fluid cannot follow,
  • void created produce tiny bubbles
  • Bubbles implode amongst themselves creating
    shock waves.
  • Heat (By product)

5
ULTRASONIC POWER
  • Phaco Power Power depends on Amplitude
    (stroke length) of phaco tip
  • Continuous Power
  • Pulse Power
  • Burst Power

6
ULTRASONIC POWER
  • Linear On pressing the foot pedal there is
    gradual rise of parameters from O to preset
    values with a linear relation to foot pedal
    control.
  • Panel On pressing foot pedal, the parameters
    reach to the preset panel values.

7

ULTRASONIC POWER
  • Constant Mode
  • Power is delivered continuously.
  • It can be linear or panel controlled.
  • Pulse mode
  • Phaco power is delivered at preset intervals.
  • It can be varied.
  • It gives relative intervals, where there is
    absence of tip movement.

8
ULTRASONIC POWER
  • Effective Phaco time
  • It is the total phaco time at 100 phaco power.
  • It can be less than total foot pedal time.
  • Less EPT indicates less energy delivered to the
    eye.

9
Irrigation
  • Gravity driven
  • IOP gt 10 mm Hg
  • wound leak reduces pressure spikes
  • Bottle height 30-75 cm
  • double irrigation for high vacuum

10
ASPIRATION SYSTEM
  • Aspiration Evacuation of fluid through a closed
    system.
  • Flow Rate Quantity of fluid pulled from the eye
    per minute through the instrument tip
  • Measured in CC/Min.

11
PERISTALTIC PUMP
  • Principle A pressure differential is created by
    compression of the aspiration tubing in a
    rotating motion.
  • Aspiration tube passes over the knobs.
  • When the drum rotates aspiration tube is
    successively compressed by the knobs over the
    drum to produce vacuum in the tubing.

12
VENTURI PUMP
  • This uses compressed gas to create inverse
    pressure.
  • Vacuum generated is related to gas flow which is
    regulated by a valve.
  • The vacuum build up is almost instantaneous on
    pressing the foot pedal.

13
Surge
  • Sudden increase in outflow uncompensated A/C
    collapse
  • High IOP and negative pressure in aspiration
    tubing

14
Surge Prevention
  • Decrease vacuum
  • decrease flow rate
  • non compliant tubes
  • tighter wound
  • raise bottle height
  • microprocessor
  • venting

15
Venting
  • Safety mechanism to limit the vacuum to
    predetermined maximum level
  • bleeding air or fluid in aspiration line.
  • Balance IOP and negative pressure in aspiration
    line

16
Rise time
17
SUPERIOR INCISION
  • BETWEEN 11 1 OCLOCK
  • Advantages
  • a. Maximum protection against infection
  • b. Easy for beginners
  • Disadvantages
  • a. Difficult to construct work in deep
    seated eyes
  • b. Poor visibility - corneal folds
  • c. Less Red Glow
  • d. Difficult in cases of filtering surgery
  • e. Maximum ATR

18
TEMPORAL INCISION
  • BETWEEN 8 10 O Clock.
  • Advantages
  • a. Easy to make/manipulate in deep seated
    eyes
  • b. Good tissue visibility
  • c. Maximum red glow
  • d. All types of cases
  • e. Less foreign body sensation
  • Disadvantages
  • a. More chances of infection
  • b. Sitting position difficult.

19
CLEAR CORNEAL INCISION
  • SIMPLE FAST
  • Diamond Blades
  • Single plane incision - single blade
  • (No groove/No cautery/ No scleral tunnel)
  • Easy for topical anesthesia
  • DISADVANTAGES
  • a. More chances of Infection
  • b. More endothelial damage
  • c. Increased astigmatism (if gt5 mm)

20
ASTIGMATIC CONSIDERATIONS
  • Incision funnel Bonded by two curved lines.
    Incisions made with in the funnel
  • Curvilinear incision - Maximum ATR
  • Straight line incision - Less ATR
  • Frown /Cheveron incision - Least ATR
  • SITE OF INCISION
  • Superior incision - More ATR
  • Supero-temporal Incision - Moderate ATR
  • Temporal Incision - Least ATR

21
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22
Methods To Enlarge Pupil
  • Sphincter sparing
  • 1. Synechiolysis
  • Old uveitis,
  • Prior surgery,
  • prolonged miotics
  • 2. Membranectomy
  • 3. Visco elastic Cohesive
  • eg. Na,Hyaluronate

23
Methods To Enlarge Pupil
  • B) Involving the sphincter
  • Pupil Stretching
  • By two instruments
  • By Prongs

24
Methods To Enlarge Pupil
  • Mini sphincterotomies
  • Grieshaber Iris hooks
  • Pupil ring expanders
  • Iridotomy

25
  • Gradual Enlargement of the Pupil is preferred
    over rapid, sudden tugging.
  • Stretching always performed under visco elastic
  • Intra cameral Lidocaine may be necessary
  • Aim for adequate pupil (Not very large)

26
Undesirable effects
  • Large sphincter tears
  • Atonic pupil, photophobia
  • Deformed pupil / Aesthetic change
  • Iris haematoma
  • Iris damage
  • Mechanical,
  • -- Thermal
  • Cost involvement
  • Post operative inflammation

27
Capsulorhexis
  • Posterior Zonular Fibres are inserted 1 to 1.5
    mm. and Anterior Zonular Fibres about 2 mm. From
    Equator.
  • Central 6 mm. is Zonule free area of the anterior
    Capsule.
  • Krag by computer simulation showed that C.C.C.
    diameter needs only to be 1/2 to 2/3 diameter of
    IOL Optic diameter.

28
  • Anterior chamber maintained

  • Visco elastic
  • Air
  • A/C maintainer.
  • Bent needle of 26 No.
  • Or Forceps can be used.
  • Shearing
  • Ripping
  • While tearing, always catch the cutting edge.

29
CCC Advantages
  • In the Bag Phaco emulsification is possible.
  • Centering of IOL is possible.
  • In case of PCR, IOL can be implanted over the
    capsular rim.
  • Chances of posterior synechiae are reduced.

30
Complications
  • Shrinkage of anterior capsular opening.
  • Capsular bag hyperdistension.
  • Epithelial cell hyperproliferation on the
    posterior capsule.

31
Hydrodissection
  • Through side port
  • No escape of fluid hence post capsular rupture
  • (Always use main incision)
  • Large Volume Fluid Trapped
  • to avoid ½ ml. at a time, at 2-3 places,
    after lifting the anterior capsule

32
Nucleus Management
  • Soft cataract/ posterior subcapsular cataract
  • SPRING Technique
  • Hard Cataract Cracking operations.
  • 1. Divide Conquer
  • 2. Stop Chop
  • 3. Quick Chop.

33
SPRING TECHNIQUE
  • Sequential Pulsed Removal of Inner Nuclear
    Girdle.
  • Central Sculpting - Broad Deep
  • Relaxing Nucleotomies 7.30, 4.30, Center.
  • Aspiration of the collapsed wings.
  • Spring with crack hybrid technique.

34
SPRING
35
DIVIDE CONQUER
  • 4 Basic steps
  • 1. Sculpting to a very thin posterior nuclear
    Plate.
  • 2. Fracturing nuclear rim and posterior plate.
  • 3. Fracturing again to break wedge shaped
    Section.
  • 4. Rotating the nucleus, further fracturing
    followed by emulsification.

36
TRENCH, DIVIDE CONQUER
  • Trench should be small, central vertical to
    leave enough firm nucleus for applying force of
    two instruments.
  • More nuclear density - fuller
    length of trenching.
  • Crack starts at the posterior pole
  • and then extends to 6 12 oclock.
  • Hemisections are then further divided.

37
CRATER, DIVIDE CONQUER
  • Deep Central Sculpting to produce large crater
    leaving dense peripheral rim, for fracturing.
  • Harder the nucleus
  • smaller the wedge shaped sections.
  • All sections are left in the bag
  • To keep it distended
  • To keep ultrasonic turbulence in bag.

38
Nagahara Chop
  • Advantage Least phaco time.
  • Disadvantage
  • Pieces rejoin and prevent their removal
  • Threat to the integrity of anterior capsule by
    chopper

39
Stop chop
  • Kochs modification
  • Trench sculpted nucleus is halved,
  • then stop and start chop.

40
PHACO QUICK CHOP (PFIFER)
  • Main difference is placement of chopper.
  • It is placed on top of the buried phaco tip near
    centre of lens- away from anterior capsular rim.

41
PHACO QUICK CHOP (PFIFER)
  • near vertical chopping.
  • Chopper pushed down, phaco tip moves up and then
    both are laterally separated.
  • Prepare all fragments before emulsifying to
    enable endo capsular phaco.
  • 2mm exposure of phaco tip.

42
Coaxial MICS
  • Use of micro tip
  • Nano sleeves
  • Incision 2 2.2 mm
  • No change in surgeons technique
  • IOLs available for insertion
  • High vacuum and phaco aspiration possible

43
P.C. Rent (INTRA-OP FACTORS)
  • Peripheral escape of rhexis
  • forceful hydrodissection
  • high vacuum and high power settings
  • one handed technique-chasing the fragments
  • sculpting too deep / too peripheral

44
POSTERIOR CAPSULAR RENT
signs
  • Sudden deepening of the AC.
  • New found difficulty in emulsifying the nucleus
  • mydriasis / pupil distortion
  • Visible vitreous in AC!!..
  • STOP!! EVALUATEPLAN..!!

45
RENT CONTROL ACTS..!!! The 10 commandments..
  • FREEZE movements,reduce bottle height
  • inject visco from side port
  • stop irrigation
  • press reflux
  • withdraw phaco tip from AC
  • Assess damage-site , extent of rent.

46
Rent control acts..!! Contd..
  • 6. Mechanized bimanual vitrectomy
  • 7. Removal of residual nuclear fragments
  • 8. Dry cortex aspiration
  • 9. Re-assess capsular support
  • and insert IOL PC / AC
  • 10.Secure wound closure
  • Post op care-antibiotics, steroids, NSAIDs
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