Overview of Phaco

Overview of PhacoOverview of Phaco

Dr. Anil Kulkarni, M.S.Dr. Anil Kulkarni, M.S.

MirajMiraj

PhacodynamicsPhacodynamics

Common TermsCommon Terms

USG powerUSG power

IrrigationIrrigation

Aspiration/ FlowAspiration/ Flow

VacuumVacuum

ACOUSTIC VIBRATORACOUSTIC VIBRATOR

Two Types Two Types

Magneto-restrictive-Magneto-restrictive-

Piezoelectric – electrical energy is used to Piezoelectric – electrical energy is used to reorient piezoelectric crystal which in turn reorient piezoelectric crystal which in turn is translated in to linear movement.is translated in to linear movement.

ULTRASONIC POWERULTRASONIC POWER

Vibration of tip – Energy releaseVibration of tip – Energy release

Jackhammer effectJackhammer effect

Cavitation : Cavitation :

when tip retreats fluid cannot follow, when tip retreats fluid cannot follow,

void created produce tiny bubbles void created produce tiny bubbles

Bubbles implode amongst themselves creating shock Bubbles implode amongst themselves creating shock waves.waves.

Heat (By product)Heat (By product)


Phaco Power : Power depends on – Phaco Power : Power depends on – Amplitude (stroke length) of phaco tip Amplitude (stroke length) of phaco tip

Continuous PowerContinuous Power

Pulse PowerPulse Power

Burst PowerBurst Power


LinearLinear – On pressing the foot pedal there is gradual – On pressing the foot pedal there is gradual rise of parameters from “O” to preset values with a rise of parameters from “O” to preset values with a linear relation to foot pedal control.linear relation to foot pedal control.

PanelPanel – On pressing foot pedal, the parameters – On pressing foot pedal, the parameters reach to the preset panel values.reach to the preset panel values.

Constant Mode – Constant Mode – Power is delivered continuously. Power is delivered continuously. It can be linear or panel controlled.It can be linear or panel controlled.

Pulse mode – Pulse mode – Phaco power is delivered at preset intervals.Phaco power is delivered at preset intervals.It can be varied. It can be varied. It gives relative intervals, where there is absence of It gives relative intervals, where there is absence of tip movement. tip movement.

ULTRASONIC POWER


Effective Phaco time – Effective Phaco time –

It is the total phaco time at 100% phaco power.It is the total phaco time at 100% phaco power.

It can be less than total foot pedal time. It can be less than total foot pedal time.

Less EPT indicates less energy delivered to the eye.Less EPT indicates less energy delivered to the eye.

IrrigationIrrigation

Gravity drivenGravity driven

IOP > 10 mm HgIOP > 10 mm Hg

wound leak reduces wound leak reduces pressure spikespressure spikes

Bottle height 30-75 cmBottle height 30-75 cm

double irrigation for double irrigation for high vacuumhigh vacuum

ASPIRATION SYSTEMASPIRATION SYSTEM

Aspiration – Evacuation of fluid through a closed Aspiration – Evacuation of fluid through a closed system.system.

Flow Rate – Quantity of fluid pulled from the eye per Flow Rate – Quantity of fluid pulled from the eye per minute through the instrument tip minute through the instrument tip

Measured in CC/Min. Measured in CC/Min.

PERISTALTIC PUMPPERISTALTIC PUMP

Principle – A pressure differential is created by Principle – A pressure differential is created by compression of the aspiration tubing in a rotating compression of the aspiration tubing in a rotating motion.motion.

• Aspiration tube passes over the knobs.Aspiration tube passes over the knobs.

• When the drum rotates aspiration tube is successively When the drum rotates aspiration tube is successively compressed by the knobs over the drum to produce compressed by the knobs over the drum to produce vacuum in the tubing.vacuum in the tubing.

VENTURI PUMPVENTURI PUMP

This uses compressed gas This uses compressed gas to create inverse pressure.to create inverse pressure.

Vacuum generated is Vacuum generated is related to gas flow which is related to gas flow which is regulated by a valve.regulated by a valve.

The vacuum build up is The vacuum build up is almost instantaneous on almost instantaneous on pressing the foot pedal. pressing the foot pedal.

SurgeSurge

Sudden increase in Sudden increase in outflow outflow uncompensated = uncompensated = A/C collapseA/C collapse

High IOP and High IOP and negative pressure in negative pressure in aspiration tubingaspiration tubing

Surge PreventionSurge Prevention Decrease vacuumDecrease vacuum

decrease flow ratedecrease flow rate

non compliant tubesnon compliant tubes

tighter woundtighter wound

raise bottle heightraise bottle height

microprocessormicroprocessor

ventingventing

VentingVenting

Safety mechanism to limit Safety mechanism to limit the vacuum to the vacuum to predetermined maximum predetermined maximum levellevel

bleeding air or fluid in bleeding air or fluid in aspiration line.aspiration line.

Balance IOP and negative Balance IOP and negative pressure in aspiration linepressure in aspiration line

Rise timeRise time

SUPERIOR INCISIONSUPERIOR INCISION

BETWEEN 11 & 1 O’CLOCKBETWEEN 11 & 1 O’CLOCK

Advantages :Advantages :

a. Maximum protection against infectiona. Maximum protection against infection

b. Easy for beginnersb. Easy for beginners

Disadvantages :Disadvantages :

a. Difficult to construct & work in deep seated eyesa. Difficult to construct & work in deep seated eyes

b. Poor visibility - corneal foldsb. Poor visibility - corneal folds

c. Less Red Glowc. Less Red Glow

d. Difficult in cases of filtering surgeryd. Difficult in cases of filtering surgery

e. Maximum ATRe. Maximum ATR

TEMPORAL INCISIONTEMPORAL INCISION

BETWEEN 8 & 10 O’ Clock.BETWEEN 8 & 10 O’ Clock.

Advantages :Advantages :

a. Easy to make/manipulate in deep seated eyesa. Easy to make/manipulate in deep seated eyes

b. Good tissue visibility b. Good tissue visibility

c. Maximum red glowc. Maximum red glow

d. All types of casesd. All types of cases

e. Less foreign body sensatione. Less foreign body sensation

Disadvantages :Disadvantages :

a. More chances of infectiona. More chances of infection

b. Sitting position difficult. b. Sitting position difficult.

CLEAR CORNEAL INCISIONCLEAR CORNEAL INCISION

SIMPLE & FASTSIMPLE & FASTDiamond BladesDiamond BladesSingle plane incision - single blade Single plane incision - single blade

(No groove/No cautery/ No scleral (No groove/No cautery/ No scleral tunnel)tunnel)Easy for topical anesthesia Easy for topical anesthesia

DISADVANTAGES :DISADVANTAGES : a. More chances of Infectiona. More chances of Infection b. More endothelial damageb. More endothelial damage c. Increased astigmatism (if >5 mm)c. Increased astigmatism (if >5 mm)

ASTIGMATIC CONSIDERATIONSASTIGMATIC CONSIDERATIONS

Incision funnel : Bonded by two curved lines. Incision funnel : Bonded by two curved lines. Incisions made with in the funnel :Incisions made with in the funnel :

Curvilinear incision - Maximum ATRCurvilinear incision - Maximum ATR

Straight line incision - Less ATRStraight line incision - Less ATR

Frown /Cheveron incision - Least ATRFrown /Cheveron incision - Least ATR

SITE OF INCISIONSITE OF INCISION

Superior incision - More ATRSuperior incision - More ATR

Supero-temporal Incision - Moderate ATRSupero-temporal Incision - Moderate ATR

Temporal Incision - Least ATRTemporal Incision - Least ATR

Methods To Enlarge PupilMethods To Enlarge Pupil

A)A) Sphincter sparingSphincter sparing1. Synechiolysis – 1. Synechiolysis –

Old uveitis, Old uveitis,

Prior surgery, Prior surgery,

prolonged mioticsprolonged miotics

2. Membranectomy2. Membranectomy

3. Visco elastic – Cohesive 3. Visco elastic – Cohesive

eg. Na,Hyaluronateeg. Na,Hyaluronate


B) Involving the sphincterB) Involving the sphincter

1.1. Pupil StretchingPupil Stretching

: By two instruments : By two instruments

: By Prongs: By Prongs


2.2. Mini sphincterotomiesMini sphincterotomies

3.3. Grieshaber Iris hooksGrieshaber Iris hooks

4.4. Pupil ring expandersPupil ring expanders

5.5. IridotomyIridotomy

Gradual Enlargement of the Pupil is Gradual Enlargement of the Pupil is preferred over rapid, sudden tugging.preferred over rapid, sudden tugging.

Stretching always performed under visco Stretching always performed under visco elasticelastic

Intra cameral Lidocaine may be necessaryIntra cameral Lidocaine may be necessary

Aim for adequate pupil (Not very large)Aim for adequate pupil (Not very large)

Undesirable effectsUndesirable effects

Large sphincter tearsLarge sphincter tears

Atonic pupil, Atonic pupil, photophobiaphotophobia

Deformed pupil / Deformed pupil / Aesthetic changeAesthetic change

Iris haematomaIris haematoma

Iris damage Iris damage

– – Mechanical,Mechanical,

-- Thermal-- Thermal

Cost involvementCost involvement

Post operative Post operative inflammation inflammation

Posterior Zonular Fibres are inserted 1 to 1.5 Posterior Zonular Fibres are inserted 1 to 1.5 mm. and Anterior Zonular Fibres about 2 mm. mm. and Anterior Zonular Fibres about 2 mm. From Equator.From Equator.

Central 6 mm. is Zonule free area of the Central 6 mm. is Zonule free area of the anterior Capsule.anterior Capsule.

Krag Krag by computer simulation showed that by computer simulation showed that C.C.C. diameter needs only to be 1/2 to 2/3 C.C.C. diameter needs only to be 1/2 to 2/3 diameter of IOL Optic diameter.diameter of IOL Optic diameter.

Capsulorhexis Capsulorhexis

Anterior chamber maintained Anterior chamber maintained

: Visco elastic : Visco elastic : Air : Air : A/C maintainer.: A/C maintainer.

Bent needle of 26 No. Bent needle of 26 No. Or Forceps can be used.Or Forceps can be used.

ShearingShearingRippingRipping

While tearing, always catch the While tearing, always catch the cutting edge.cutting edge.

CCC AdvantagesCCC Advantages

In the Bag Phaco emulsification is possible.In the Bag Phaco emulsification is possible.

Centering of IOL is possible.Centering of IOL is possible.

In case of PCR, IOL can be implanted over the In case of PCR, IOL can be implanted over the capsular rim.capsular rim.

Chances of posterior synechiae are reduced.Chances of posterior synechiae are reduced.

Shrinkage of anterior capsular opening.Shrinkage of anterior capsular opening.

Capsular bag hyperdistension.Capsular bag hyperdistension.

Epithelial cell hyperproliferation on the Epithelial cell hyperproliferation on the posterior capsule.posterior capsule.

Complications

HydrodissectionHydrodissection

Through side port : Through side port : No escape of fluid & hence No escape of fluid & hence post capsular rupture post capsular rupture ((Always use main incision)Always use main incision)

Large Volume Fluid TrappedLarge Volume Fluid Trapped [ to avoid – ½ ml. at a time, [ to avoid – ½ ml. at a time,

at 2-3 places, at 2-3 places, after lifting after lifting the the anterior capsule]anterior capsule]

Soft cataract/ posterior subcapsular cataractSoft cataract/ posterior subcapsular cataract

SPRING TechniqueSPRING Technique

Hard Cataract : Hard Cataract : Cracking operations. Cracking operations.

1. Divide & Conquer1. Divide & Conquer

2. Stop & Chop2. Stop & Chop

3. Quick Chop.3. Quick Chop.

Nucleus ManagementNucleus Management

SPRING TECHNIQUESPRING TECHNIQUE

SSequential equential PPulsed ulsed RRemoval of emoval of IInner nner NNuclear uclear GGirdle.irdle.

Central Sculpting - Broad & DeepCentral Sculpting - Broad & Deep

Relaxing Nucleotomies 7.30, 4.30, Center.Relaxing Nucleotomies 7.30, 4.30, Center.

Aspiration of the collapsed wings.Aspiration of the collapsed wings.

Spring with crack hybrid technique.Spring with crack hybrid technique.

SPRINGSPRING

DIVIDE & CONQUER DIVIDE & CONQUER

4 Basic steps :4 Basic steps :

1. Sculpting to a very thin posterior nuclear Plate.1. Sculpting to a very thin posterior nuclear Plate.

2. Fracturing nuclear rim and posterior plate.2. Fracturing nuclear rim and posterior plate.

3. Fracturing again to break wedge shaped Section.3. Fracturing again to break wedge shaped Section.

4. Rotating the nucleus, further fracturing followed by 4. Rotating the nucleus, further fracturing followed by emulsification.emulsification.

TRENCH, DIVIDE & CONQUERTRENCH, DIVIDE & CONQUER

Trench should be small, central & Trench should be small, central & vertical to leave enough firm nucleus for vertical to leave enough firm nucleus for applying force of two instruments.applying force of two instruments.

More nuclear density - More nuclear density - fuller length of trenching.fuller length of trenching.

Crack starts at the posterior pole Crack starts at the posterior pole

and then extends to 6 & 12 o’clock. and then extends to 6 & 12 o’clock.

Hemisections are then further divided.Hemisections are then further divided.

CRATER, DIVIDE & CONQUERCRATER, DIVIDE & CONQUER

Deep Central Sculpting to produce Deep Central Sculpting to produce large crater leaving dense large crater leaving dense peripheral rim, for fracturing.peripheral rim, for fracturing.

Harder the nucleus – Harder the nucleus –

smaller the wedge shaped sections.smaller the wedge shaped sections.

All sections are left in the bag:All sections are left in the bag:

To keep it distended ;To keep it distended ;

To keep ultrasonic turbulence in To keep ultrasonic turbulence in bag.bag.

Nagahara ChopNagahara Chop

Advantage : Least phaco time.Advantage : Least phaco time.

Disadvantage: Disadvantage:

Pieces rejoin and prevent their removalPieces rejoin and prevent their removal

Threat to the integrity of anterior capsule by chopperThreat to the integrity of anterior capsule by chopper

Stop & chopStop & chop

Koch’s modification :Koch’s modification :

Trench sculpted & nucleus Trench sculpted & nucleus is halved,is halved,

then stop and start chop.then stop and start chop.

PHACO QUICK CHOP (PFIFER)PHACO QUICK CHOP (PFIFER)

Main difference is placement of chopper.Main difference is placement of chopper.

It is placed on top of the buried phaco tip near centre of lens- away It is placed on top of the buried phaco tip near centre of lens- away from anterior capsular rim.from anterior capsular rim.

PHACO QUICK CHOP (PFIFER)PHACO QUICK CHOP (PFIFER)

near vertical chopping.near vertical chopping.

Chopper pushed down, phaco tip moves Chopper pushed down, phaco tip moves up and then both are laterally separated. up and then both are laterally separated.

Prepare all fragments before emulsifying Prepare all fragments before emulsifying to enable endo capsular phaco.to enable endo capsular phaco.

2mm exposure of phaco tip.2mm exposure of phaco tip.

Coaxial MICSCoaxial MICS

Use of micro tipUse of micro tip

Nano sleevesNano sleeves

Incision 2 – 2.2 mmIncision 2 – 2.2 mm

No change in surgeon’s techniqueNo change in surgeon’s technique

IOLs available for insertionIOLs available for insertion

High vacuum and phaco aspiration possibleHigh vacuum and phaco aspiration possible

P.C. Rent (INTRA-OP FACTORS)P.C. Rent (INTRA-OP FACTORS)

Peripheral escape of rhexisPeripheral escape of rhexis

forceful hydrodissectionforceful hydrodissection

high vacuum and high power settingshigh vacuum and high power settings

one handed technique-chasing the fragmentsone handed technique-chasing the fragments

sculpting too deep / too peripheralsculpting too deep / too peripheral

POSTERIOR CAPSULAR RENTPOSTERIOR CAPSULAR RENT

signssigns

Sudden deepening of the AC.Sudden deepening of the AC.

New found difficulty in emulsifying the nucleus…New found difficulty in emulsifying the nucleus…

mydriasis / pupil distortionmydriasis / pupil distortion

Visible vitreous in AC!!.. Visible vitreous in AC!!..

STOP!! EVALUATE…PLAN..!!STOP!! EVALUATE…PLAN..!!

RENT CONTROL ACTS..!!!RENT CONTROL ACTS..!!! The 10 commandments..The 10 commandments..

1.1. FREEZE movements,reduce bottle heightFREEZE movements,reduce bottle height

2.2. inject visco from side portinject visco from side port

3.3. stop irrigationstop irrigation

4.4. press refluxpress reflux

5.5. withdraw phaco tip from ACwithdraw phaco tip from AC Assess damage-site , extent of rent.Assess damage-site , extent of rent.

Rent control acts..!! Contd..Rent control acts..!! Contd..

6. Mechanized bimanual vitrectomy6. Mechanized bimanual vitrectomy

7. Removal of residual nuclear fragments7. Removal of residual nuclear fragments

8. Dry cortex aspiration8. Dry cortex aspiration

9. Re-assess capsular support9. Re-assess capsular support and insert IOL …PC / AC and insert IOL …PC / AC

10.Secure wound closure10.Secure wound closure

Post op care-antibiotics, steroids, NSAIDs Post op care-antibiotics, steroids, NSAIDs

Documents

Overview of Phaco