Cataract surgery
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Cataract surgery

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This presentation is orginaly uploaded to http://kpkmedicalcolleges.tk by Dr.Suleman

This presentation is orginaly uploaded to http://kpkmedicalcolleges.tk by Dr.Suleman

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Cataract surgery Cataract surgery Presentation Transcript

  • Intra capsular cataract extraction (ICCE) ICCE  ICCE evolved into a very successful operation  Preferred surgical technique before the refinement of modern ECCE surgery  However there remained 5% rate of potentially blinding complications including:     Infection Hemorrhage RD CME
  • Intra capsular cataract extraction (ICCE)  ECCE has replaced ICCE, almost entirely in most parts of the world: 1. Better operating microscopes 2. More sophisticated surgical aspiration systems 3. More sophisticated IOL implants
  • Techniques (ICCE)  Smith’s method  Arruga’s method  Erysiphakes  Cryo surgery  Chemical dissolution of zonular fibers
  • Smith’s technique  Smith used external pressure with muscle hook to mechanically break the inferior zonules  Expelled the lens through the limbal incision  The lens would “Tumble”, I.e. the inferior pole would exit the eye before the superior pole
  • Arruga’s method  Toothless forceps (Arruga’s) used to grasp the lens capsule and then gently pulled from the eye using side-to-side motion that broke the zonules
  • Arruga’s Forceps
  • Erysiphakes technique  Suction cuplike devices were used to remove the lens with traction
  • Cryo surgery  Cryprobe: Hollow metal-tipped probe, cooled by liquid nitrogen, that is touched to the lens surface  As the temperature of the probe tip falls below freezing, an ice ball forms and the lens adheres to it  This instrument forms an ice ball, fusing the lens capsule, cortex, and nucleus  Lessening the risk of capsular rupture as the cataract is removed
  • Chemical dissolution of zonular fibers  The enzyme is irrigated into posterior chamber to dissolve the zonular fibers in order to facilitate ICCE surgery  Enzyme alpha-chymotrypsin enhances the safety of ICCE by increasing the ease of lens removal
  • Extra capsular cataract extraction (ECCE)  Shift from ICCE to modern ECCE  To decrease the rate of potentially blinding:  Complications  To facilitate the placement of PC IOLs  By leaving the PC intact, the surgeon could decrease the risk of:  Vitreous loss and  Complications like RD, CME, and Bullous Keratopathy
  • Extra capsular cataract extraction (ECCE)  Key to the development of modern ECCE technique were the growing use of:  Operating microscopes for increased magnification &  Improved methods of cortical removal
  • Extra capsular cataract extraction (ECCE)  Charles Kelman in 1967 developed phacoemulsification  This new type of ECCE:  Ultrasonically emulsified the lens nucleus,  Allowing the operation to be performed through a small incision  This method has continued to grow in popularity as:  Techniques &  Instrumentation
  • Indications of ICCE  Operating microscopes not available  Unstable / luxated cataracts  Week zonular support
  • Advantages of ICCE • Entire lens removed with no capsule left behind to: • Opacify or • Require additional surgery • Less sophisticated instrumentation required • Non automated extraction devices: Cryoprobes Capsular forceps Erysiphakes Allow this procedure To be performed Under most conditions
  • Disadvantages of ICCE • Large ICCE incision 12 – 14 mm (160° - 180°)   Delayed healing Iris incarceration  Delayed visual rehabilitation  Vitreous incarceration • Postoperative wound leaks with inadvertent filteration • Endothelial cell loss > following ICCE than ECCE • Corneal / endothelial cell trauma from lifting / folding of the cornea (lens delivery / cryprobe) • Cystoid macular edema (transient 50%, persistent 2% - 4%)
  • Disadvantages of ICCE (cont’d)  Vitreous complications: In young patients PC is firmly adherent to anterior hyaloid; attempted ICCE will usually result in vitreous loss  Intact vitreous face may opacify and ↓ vision  Adherence to corneal endothelium (corneal edema)  Adherence to iris (pupillary block glaucoma)  Broken vitreous face may incarcerate in the wound with vitreous traction causing:  RD  CME  Vitreous in AC causing open angle glaucoma
  • Disadvantages of ICCE (cont’d)  IOL implantation problematic since posterior capsular support missing  IOL choices include:  ACL /Sutured PC IOL (Iris fixation IOLs no longer available)  These significant disadvantages and risks led to loss of popularity of ICCE
  • Patient preparation  Pharmacologic pupillary dilation with topical mydriatic and cycloplegic agents to facilitate lens removal (iris retractors intraoperatively)  Anaesthesia
  • Patient preparation  (cont’d) Orbital massage / osmotic agents (manitol, glycerine, isosorbide) before surgery 1. Intermittent digital pressure on closed eye lids or 2. Occulopressive device (honann baloon, mercury bag, sponge ball, strap) 3. Massage helps to:  Distribute the anaesthetic agent within orbit  ↓ Orbital volume  ↓ Pressure on the globe  ↓ IOP
  • Patient preparation (cont’d) Orbital massage (cont’d) 4. Minimizes vitreous prolapse during cataract extraction and facilitates an angle supported IOL 5. Osmotic agents are used less frequently:  Volume load in patients with heart and kidney failure  Nausea (Occasional)  Urinary urgency during surgery
  • Patient preparation (cont’d)  Procedure  Postoperative course VA should be consistent with: 1. Refractive state of the eye 2. Clarity of the cornea 3. Clarity of the media 4. Visual potential of the retina and optic nerve
  • Patient preparation (cont’d)  ECCE  ECCE involves removal of the nucleus and cortex through an opening in the anterior capsule (anterior capsulotomy), leaving the posterior capsule in place.
  • Patient preparation (cont’d) ECCE (cont’d) Methods 1. Nucleus expression (manual) 2. Phacoemulsification (Ultrasonic fragmentation)
  • Patient preparation (cont’d) ECCE (cont’d) Methods  Preferred method of routine cataract surgery  Selection of technique for nucleus removal depends upon:  Instrumentation available  Surgeon’s level of experience with each technique
  • Advantages of ECCE surgery (cont’d)  Smaller incision  Less traumatic to corneal endothelium  Eliminates complications (short and long term) associated with vitreous adherent to:  Incision wound  Iris  Cornea
  • Advantages of ECCE surgery (cont’d)  Intact posterior capsule allows better anatomical position for IOL fixation  Intact posterior capsule ↓ incidence of:  CME  RD  Corneal edema
  • Advantages of ECCE surgery (cont’d)  Intact posterior capsule ↓ ability of bacteria, introduced into eye, to gain access to vitreous cavity and cause endophthalmitis     2ndry IOL implantation Filtration surgery Corneal Transplantation Wound rapair Technically easier and safer when intact PC is present
  • Contraindications (ECCE)  Zonular weakness  ECCE requires zonular integrity for selective removal of nucleus and cortical material  Therefore when zonular support appears insufficient to allow safe removal of the cataract through ECCE surgery, ICCE or Pars Plana Lensectomy should be considered
  • Instrumentation (ECCE)  A wide range of instruments is available for each step of ECCE:  Opening the anterior capsule  Dissecting and removing the nucleus  Removing the lens cortex  Polishing PC
  • Cystotome  Used for anterior capsulotomy (opening in the anterior of the lens)  Fashioned from 25 gauge needles by bending at its hub and beveled tip  Prefabricated cystotomes also commercially available  The needle tip is used to puncture and tear the anterior capsule
  • Irrigation and aspiration system coaxial, double-lumen blunt cannulas  One lumen irrigates BSS into the AC  Second lumen aspirates lens material out of the AC  Irrigation is gravity fed from a solution bottle  Fluid flow is regulated with adjustment of bottle height  The flow may be constant, or the surgeon can employ a foot control connected to a pinch valve
  • Irrigation and aspiration system coaxial, double-lumen blunt cannulas (cont’d) Aspiration:  Syringe connected to the cannula  Elaborate pump system controlled by a foot switch
  • Lens nucleus Removed by a variety of techniques, each with its own set of instruments:  Lens expressor  Lens loop  Spoon, Vectis
  • Procedure ECCE  Pupillary dilation  Critical to the success of ECCE esp. phacoemulsification  Cycloplegic / mydriatic drops  NSAID (topical/oral) these agents help to maintain dialation during surgery
  • Procedure ECCE (cont’d)  Incision  Incision: Mid limbal, chord length 8 – 12 mm, which is smaller than for ICCE  The initial incision consists of a limbal groove  Some surgeons prefer more posterior incision with anterior dissection creating a flap of tunnel  A stab incision is made into AC  AC depth stabilized by viscoelastic agents, air bubble, or continuous fluid irrigation  Cystotome is inserted for anterior capsulotomy
  • Procedure ECCE  Capsulotomy  Christmas tree  Can-opener  Capsulorrhexis (cont’d)
  • Procedure ECCE (cont’d) Capsulotomy (cont’d) Christmas tree  With cystotome anterior capsule punctured inferiorly and  The flap of the capsule drawn toward the wound and cut with scissors
  • Procedure ECCE (cont’d) Capsulotomy (cont’d) Can-Opener  Cystotome used to make a series of connected punctures or small tears in circle
  • Procedure ECCE (cont’d)  Capsulorrhexis  Continuous tear anterior capsulotomy popular in phacoemulsification, can be performed with either:  Csytotome or  Capsulorrhexis forceps  First a small tear is created,  The edge this tear is then grasped with cytotome tip/forceps, and  A smooth tear is created, removing a circular portion of anterior capsule
  • Procedure ECCE (cont’d)  Capsulorrhexis (cont’d)  This technique provides:  Structural integrity for the lens capsule  Maintain implant stability  Centeration
  • Nuclear expression  Manual 1. Whole (Lens loop, spoon, vectis, irrigation) 2. Fragmentation with forceps/nuclear splitter)  Ultrasonic fragmentation
  • Lens cortex aspiration 1. Syringe connected to cannula 2. Pump system controlled by foot switch
  • Posterior capsular polishing  Abrasive tipped irrigation cannula / low vacuum clean using low aspiration remove epithelial and cortical particles from the capsular surface
  • IOL implantation      AC filled with viscoelastic / BBS / air Viscoelastic most reliable AC maintainer It also protects corneal endothelial IOL inserted in the ciliary sulcus / capsular bag Sulcus fixation:  Requires greater IOL diameter (>12.5 mm)  Large diameter optic (6 mm)  More forgiving in case of postoperative decentration  Bag fixation:  IOL diameter <12.5 mm  Optic diameter 5.00 mm
  • Wound suturing  10/0 Nylon  Proper suture tension ↓ postoperative Astigmatism  Loose sutures – Against-the-rule Astigmatism  Tight sutures – With-the rule Astigmatism
  • Postoperative course ECCE  As with ICCE, VA on the first postoperative day should be consistent with:  Refractive state of the eye  Clarity of the cornea  Clarity of the media  Visual potential of the retina and optic nerve
  • Postoperative course ECCE  Lid: Mild eye lid edema and erythema may occur  Conjunctiva: May be injected and boggy  Cornea: Should be clear and free of striate / edema  AC: Should be of normal depth and mild cellular reaction typical
  • Postoperative course ECCE (cont’d)  Posterior capsule: Should be clear and intact  Implant: Should be well positioned and stable  Red reflex: Should be strong and clear  IOP: Elevations may be associated with retained viscoelastic
  • Postoperative course ECCE Antibiotics and Corticosteroids:  Topical antibiotic and corticosteroids are used for first few weeks Vision:  Steady improvement in vision and comfort, as inflammation subsides
  • Postoperative course ECCE (Cont’d) Refraction:  Refraction stable by 6th – 8th weeks,  Glasses may then be prescribed Astigmatism:  If significant astigmatism along the axis of incision, selective sutures removed by 6th week, according to keratometry corneal topography
  • Phacoemulsification  Phacoemulsification is an ECCE technique that differs from “standard ECCE with nuclear expression” by the: 1. Size of incision required 2. Method of nucleus removal  This technique uses ultrasonically driven needle (phaco tip) to fragment the nucleus and aspirate the lens substance through a needle port
  • Phacoemulsification (cont’d) Advantages   Lower incidence of wound related complications  Faster healing  Rapid visual rehabilitation  AC depth controlled during surgery and providing safeguards against positive vitreous pressure and choroidal haemorrhage (closed system)
  • Phacoemulsification (cont’d)  Instrumentation  Ultrasound  Irrigation system  Aspiration system
  • Phacoemulsification (cont’d)  Ultrasound  The phacoemulsification hand piece contains a piezoelectic crystal that vibrates at frequency of 24000 – 56000 Hz  The vibration is transmitted to the head which is attached to the phaco tip
  • Phacoemulsification (cont’d)  Aspiration  The aspiration system of phacoemulsification machine varies according to the pump design: 1. Peristaltic Pump 2. Diaphragm Pump 3. Venture Pump
  • Phacoemulsification (cont’d)  Aspiration (cont’d)  Peristaltic Pump  Consists of set of rollers that move along a flexible tubing, forcing fluid through the tubing and creating a relative vacuum at the aspiration port of phacoemulsification needle
  • Phacoemulsification (cont’d)  Aspiration (cont’d)  Diaphragm Pump  Flexible diaphragm overlying a fluid chamber with one-way valves at the inlet and outlet
  • Phacoemulsification (cont’d) Aspiration (cont’d)   Venturi Pump  Creates a vacuum based on the venturi principle:- That a flow of gas across a port creates a vacuum proportional to the rate of the gas
  • Phacoemulsification  Irrigation  Fluid dynamics of phacoemulsification requires constant irrigation through the irrigation sleeve around the ultrasound tip  Constant irrigation:  Maintains AC depth  Cools the phacoemulsification probe  Prevents heat buildup and adjacent tissue damage