- •Preface
- •Contributors
- •Contents
- •Introduction
- •Literature Review
- •Major Issues
- •Major Studies
- •Negative Studies
- •References
- •1.1.1 Introduction
- •1.1.3 Torsional Ultrasound
- •1.1.4 Our Procedure for Emulsifying the Nucleus
- •References
- •1.2 Transitioning to Bimanual MICS
- •1.2.1 Introduction
- •1.2.2 Technique
- •1.2.3 Summary
- •1.3 0.7 mm Microincision Cataract Surgery
- •1.3.1 Sub 1 mm MICS: Why?
- •1.3.3 Instrumentation
- •1.3.3.2 0.7 mm Irrigating Instruments
- •1.3.4 Surgery
- •1.3.4.1 Incision
- •1.3.4.2 Capsulorhexis
- •1.3.4.3 Hydrodissection
- •1.3.4.4 Prechopping
- •1.3.5 0.7 mm MICS Combined Procedures
- •1.3.5.1 0.7 mm MICS and Glaucoma Surgery
- •1.3.6 Summary
- •References
- •2. MICS Instrumentation
- •2.1 MICS Instrument Choice: The First Step in the Transition
- •2.2 MICS Incision
- •2.3 MICS Capsulorhexis
- •2.4 MICS Prechopping
- •2.5 MICS Irrigation/Aspiration Instruments
- •2.5.1 19 G Instruments
- •2.5.2 21 G Instruments
- •2.6 MICS Auxiliary Instrument
- •2.6.1 Scissors
- •2.6.2 Gas Forced Infusion
- •2.6.3 Surge Prevention
- •2.7 New MICS Instruments
- •2.7.1 Flat Instruments
- •References
- •3.1 Introduction
- •3.2 Power Generation
- •3.3.1 Tuning
- •3.2.2 Phaco Energy
- •3.2.2.1 Low Frequency Energy
- •3.2.2.2 High Frequency Energy
- •3.2.3 Transient Cavitation
- •3.2.4 Sustained Cavitation
- •3.3.1 Alteration of Stroke Length
- •3.3.2 Alteration of Duration
- •3.3.2.1 Burst Mode
- •3.3.2.2 Pulse Mode
- •Micro Pulse (Hyper-Pulse)
- •Pulse Shaping
- •3.3.3 Alteration of Emission
- •3.4 Fluidics
- •3.5 Vacuum Sources
- •3.6 Surge
- •3.7.1 Micro-incisional Phaco
- •3.7.2 Bimanual Micro-Incisional Phaco
- •3.7.3 Micro-Incisional Coaxial Phaco
- •3.7.3.1 Irrigation and Aspiration
- •3.8 Conclusion
- •Reference
- •Further Reading
- •4.1 Introduction
- •4.3 Incision Size
- •4.4 Torsional Ultrasound
- •4.5 Conclusion
- •References
- •5. Technology Available
- •5.1 How to Better Use Fluidics with MICS
- •5.1.1 Physical Considerations
- •5.1.1.2 Chamber Stability
- •5.1.1.3 Holdability
- •5.1.2 Surgical Considerations
- •5.1.2.2 Phaco Technique
- •5.1.2.4 The OS3 and CataRhex SwissTech Platforms
- •Equipment
- •Machine Settings
- •5.2 How to Use Power Modulation in MICS
- •5.2.1 Introduction
- •5.2.3 The Concept of Unoccluded Flow Vacuum
- •5.2.4 The Intricacies of Ultrasound Power Modulation
- •5.2.5 The Variable Incidence of Wound Burn Rates
- •References
- •5.3 MICS with Different Platforms
- •5.3.1 MICS with the Accurus Surgical System
- •5.3.1.1 Introduction and Historic Background
- •5.3.1.3 Surgical Parameters for MICS with Accurus
- •5.3.1.4 Final Considerations
- •5.3.2.1 Introduction
- •5.3.2.7 Technology for MICS on the AMO Signature
- •5.3.2.8 Applying Signature Technology to CMICS and BMICS
- •5.3.3 MICS with Different Platforms: Stellaris Vision Enhancement System
- •5.3.3.2 Evaluating the Stellaris Vision Enhancement System
- •5.3.3.3 The Advantages of BMICS
- •References
- •6.1 Pupil Dilation and Preoperative Preparation
- •6.1.1 Managing the Small Pupil
- •6.1.2 Techniques that Depend on the Manipulation of the Pupil
- •6.1.3 Iris Surgery
- •6.1.4 Preoperative Preparation and Infection Prophylaxis
- •6.1.5 Evaluating Risk
- •6.1.6 Assessing Your Approach
- •6.1.7 Preventing Infection, Step by Step
- •6.1.8 Sample Protocol Outline
- •6.1.9 A Careful, Critical Eye
- •References
- •6.2 Incisions
- •References
- •6.3 Thermodynamics
- •6.3.1 Introduction
- •6.3.2 Corneal Thermal Damage
- •6.3.3 Heat Generation
- •6.3.4 Factors that Contribute to Thermal Incision Damage
- •6.3.4.1 Energy Emission: Amount and Pattern of How the Energy Is Delivered
- •6.3.4.3 Viscoelastic Devices and Possible Occlusion of the Aspiration Line
- •6.3.4.4 Irrigation Flow
- •6.3.4.5 Position of the Tip Inside the Incision
- •6.3.4.6 Tip Design
- •6.3.4.7 Surgical Technique
- •6.3.5 Conclusion
- •6.4 Using Ophthalmic Viscosurgical Devices with Smaller Incisions
- •6.4.1 Introduction
- •6.4.1.1 The Nature of OVDs: Rheology
- •6.4.1.3 Soft Shell and Ultimate Soft Shell Technique (SST & USST)
- •6.4.2 Routine, Special and complicated Cases
- •6.4.2.1 Phakic and Anterior Chamber IOLs
- •6.4.2.3 Fuchs’ Endothelial Dystrophy
- •6.4.2.5 Capsular Staining for White & Black Cataracts
- •6.4.2.6 Flomax® Intraoperative Floppy Iris Syndrome USST
- •6.4.3 Discussion
- •References
- •6.5 Capsulorhexis
- •References
- •References
- •6.7 Biaxial Microincision Cataract Surgery: Techniques and Sample Surgical Parameters
- •6.8.1 Surgical Technique
- •6.8.2 Advantages
- •6.8.3 Disadvantages
- •6.8.4 Final Thoughts
- •References
- •6.9 BiMICS vs. CoMICS: Our Actual Technique (Bimanual Micro Cataract Surgery vs. Coaxial Micro Cataract Surgery)
- •6.9.1 Introduction
- •6.9.2 Historical Background
- •6.9.3 BiMICS. BiManual MicroIncision Cataract Surgery
- •6.9.3.1 Introduction
- •6.9.3.2 Instrumentation
- •6.9.3.5 Phacotips
- •6.9.3.6 Capsulorhexis
- •6.9.3.7 Phaco Knives
- •6.9.3.8 The Phaco Machines
- •6.9.3.9 Phaco Pumps
- •6.9.3.10 Ultrasound Power Delivery
- •6.9.3.11 IOL Implantation
- •6.9.3.12 Astigmatism
- •6.9.4.1 Capsulorhexis
- •6.9.4.2 Phacotips
- •6.9.4.3 The Phaco Machines
- •6.9.4.4 Phaco Pumps
- •6.9.4.5 Ultrasound Power Delivery
- •6.9.4.6 Irrigation-Aspiration
- •6.9.4.7 Incision-Assisted IOL Implantation
- •6.9.5 Conclusion
- •References
- •6.10 Endophthalmitis Prevention
- •6.10.1 Antibiotic Prophylaxis
- •6.10.2 Wound Construction
- •6.10.3 Summary
- •References
- •7.1 High Myopia
- •7.2 Posterior Polar Cataract
- •7.3 Posterior Subluxed Cataracts
- •7.4 Mature Cataract with Zonular Dialysis
- •7.5 Punctured Posterior Capsule
- •7.6 Posterior Capsule Rupture
- •7.7 Pseudoexfoliation
- •7.8 Rock-Hard Nuclei
- •7.9 Switching Hands
- •7.10 Microcornea or Microphthalmos
- •7.11 Large Iridodialysis and Zonular Defects
- •7.12 Intraoperative Floppy Iris Syndrome (IFIS)
- •7.14 Iris Bombé
- •7.15 Very Shallow Anterior Chambers
- •7.16 Refractive Lens Exchange
- •7.18 Intraocular Cautery
- •7.19 Biaxial Microincision Instruments
- •References
- •7.1 MICS in Special Cases: Incomplete Capsulorhexis
- •7.1.1 Introduction
- •7.1.2 Avoiding Complications While Constructing Your Microcapsulorhexis
- •7.1.3 Avoiding Complications During Biaxial Phaco with an Incomplete Capsulorhexis
- •7.1.4 Avoiding Complications During IOL Insertion with an Incomplete Capsulorhexis
- •7.1.5 Conclusions
- •References
- •7.2 MICS in Special Cases (on CD): Vitreous Loss
- •7.2.1 Introduction
- •7.2.2 Posterior Capsule Tears and Vitreous Prolapse
- •7.2.3 Vitreous and the Epinucleus or Cortex
- •7.2.4 Different Techniques Other than Pars Plana Vitrectomy for Nuclear Loss in Vitreous
- •7.2.5 Pars Plana Vitrectomy
- •7.2.6 Zonulolysis
- •References
- •7.3 How to Deal with Very Hard and Intumescent Cataracts
- •7.3.1 Introduction
- •7.3.2 Types of Cataracts
- •7.3.3 Management of Hard Cataracts Through Biaxial Technique
- •7.3.4 Incision
- •7.3.5 Capsulorrhexis
- •7.3.6 Hydrodissection
- •7.3.8 Conclusion
- •References
- •8. IOL Types and Implantation Techniques
- •8.1 MICS Intraocular Lenses
- •8.1.1 Introduction
- •8.1.2 Lenses
- •8.1.2.2 ThinOptX MICS IOLs (ThinOptX, Abingdon, VA)
- •8.1.2.3 Akreos MI60 AO Micro Incision IOL (Bausch & Lomb, Rochester, NY)
- •8.1.2.4 IOLtech MICS lens (IOLtech, La Rochelle, France; and Carl Zeiss Meditec, Stuttgard, Germany)
- •8.1.3 Optical Quality of MICS IOLs
- •8.1.4 Conclusion
- •References
- •8.2 Implantation Techniques
- •8.2.2 Prerequisites to a Sub-2 Injection
- •8.2.3 IOLs Used for Injection Through Microincision
- •8.2.3.1 Material
- •8.2.3.2 Design
- •8.2.3.3 Optic Design
- •8.2.3.4 Haptic Design
- •8.2.3.5 Posterior Barrier (360°)
- •8.2.4 Injectors Meant for Microincision
- •8.2.4.1 Objectives of Injectors Meant for Microincision
- •8.2.4.2 Characteristics of Sub-2 Injectors
- •8.2.4.3 The Cartridges
- •Loading Chambers
- •Injection Tunnels and Cartridge Tips
- •8.2.4.4 The Plunger Tips (or plunger)
- •8.2.4.5 Pushing Systems
- •8.2.4.6 Injector Bodies
- •8.2.4.7 Principal Sub-2 Injectors
- •8.2.5 Visco Elastic Substances and Injection Through Microincision
- •8.2.6 Techniques of Sub-2 Injection
- •8.2.6.2 Incision Construction
- •8.2.6.3 Pressurization of the Anterior Chamber
- •8.2.6.4 Loading the Cartridge
- •8.2.6.5 Loading the Injector
- •8.2.6.6 Insertion of the Plunger Tip
- •8.2.6.7 Injection in the Anterior Chamber
- •8.2.6.8 Positioning the IOL in the Capsular Bag
- •8.2.6.9 Removing the VES
- •8.2.6.10 Thin Roller Injector
- •8.2.6.11 Conclusion
- •Reference
- •8.3 Special Lenses
- •8.3.1 Toric Posterior Chamber Intraocular Lenses in Cataract Surgery and Refractive Lens Exchange
- •8.3.1.1 Introduction
- •8.3.1.3 T-IOL Calculation
- •8.3.1.4 Current T-IOL Models
- •8.3.1.5 Preoperative Marking
- •8.3.1.6 Clinical Indications
- •8.3.1.7 Custom-Made Lenses
- •8.3.1.8 Conclusion for Practice
- •References
- •8.3.2 Special Lenses: MF
- •8.3.2.1 Discussion
- •8.3.2.2 Conclusion
- •8.3.2.3 Outlook
- •References
- •8.3.3 Special Lenses: Aspheric
- •References
- •8.3.4 Intraocular Lenses to Restore and Preserve Vision Following Cataract Surgery
- •8.3.4.1 Introduction
- •8.3.4.2 Why Filter Blue Light?
- •Summary
- •8.3.4.3 Importance of Blue Light to Cataract and Refractive Lens Exchange Patients
- •Summary
- •8.3.4.4 Quality of Vision with Blue Light Filtering IOLs
- •Summary
- •8.3.4.5 Clinical Experience
- •Summary
- •8.3.4.6 Unresolved Issues and Future Considerations
- •References
- •8.3.5 Microincision Intraocular Lenses: Others
- •8.3.5.1 ThinOptX®
- •8.3.5.2 Smart IOL
- •8.3.5.4 AcriTec
- •8.3.5.5 Akreos
- •8.3.5.7 Rayner
- •8.3.5.8 Injectable Polymers
- •8.3.5.9 Final Comments
- •References
- •9. Outcomes
- •9.1 Safety: MICS versus Coaxial Phaco
- •9.1.1 Introduction
- •9.1.2 Visual Outcomes
- •9.1.3 Incision Damage
- •9.1.4 Corneal Incision Burn
- •9.1.5 Corneal Changes
- •9.1.6 Infection
- •9.1.7 Summary
- •References
- •9.2 Control of Corneal Astigmatism and Aberrations
- •9.2.1 Introduction: Impacts of MICS Incision on the Outcomes of Cataract Surgery
- •9.2.2 Objective Evaluation of Corneal Incision
- •9.2.3 Control of Corneal Aberration and Astigmatism with MICS
- •9.2.4 Role of Corneal Aberrometry in Evaluating MICS Incision
- •9.2.5 Role of OCT in Evaluating MICS Incision
- •9.2.6 Our Experience in Corneal Aberrations and Astigmatism After MICS
- •9.2.7 Conclusion
- •References
- •9.3 Corneal Endothelium and Other Safety Issues
- •9.4 Incision Quality in MICS
- •9.4.1 Introduction: History of Incision Size Reduction
- •9.4.2 The Trends Towards Microincision Cataract Surgery (BMICS)
- •9.4.3 Advantages of Minimizing the Incision Size
- •9.4.4 Model for the Analysis of Corneal Incision Quality [21]
- •9.4.5 Our Protocol for Evaluation of Incision Quality in BMICS [21]
- •9.4.6 Results
- •9.4.6.1 Visual, Refractive and Biomicroscopic Outcomes
- •9.4.6.2 Incision Imaging (OCT) Outcomes
- •9.4.8 Conclusion
- •References
- •INDEX
Evolution of Ultrasound Pumps and |
3 |
Fluidics and Ultrasound Power: From |
Standard Coaxial Towards the Minimal
Incision Possible in Cataract Surgery
William J. Fishkind
Core Messages
ßIncreased capability of the phaco machine permits a considerable individualization of the phaco parameters.
ßThrough consideration of machine settings, the quality of cataract surgery and its outcomes can be appreciably improved.
3.1 Introduction
Although phacoemulsification machines have undergone continuous improvement, ever-increasing in both, their complexity and safety, one principle remains unchanged: All phaco machines consist of a computer to generate ultrasonic energy, and a transducer to turn these electronic signals into mechanical, acoustical, and cavitational energy. The energy thus produced, is transferred through a hollow needle and will overcome the inertia of the lens to emulsify it. The second of the refined elements of the machine are the “fluidic control systems.” These consist of a vacuum generating pump and computer algorithms to control it, phaco needles of varying diameters and configurations, and infusion sources.
Frequency is defined as the speed of the needle movement. The manufacturer of the machine determines it. Presently, most machines operate at a frequency between 27,000 cycles per second (Hz) to 50,000 cycles per second. This frequency range is efficient for nuclear emulsification. Lower frequencies become less efficient and higher frequencies create excess heat.
Stroke length is defined as the length of the needle movement. This length is generally 2–6 mils (thousandths of an inch). Most machines operate in the 2–4 mil range. One mil is 25 mm. Therefore, most phaco needles travel a distance of 50–100 mm. Longer stroke lengths and higher frequencies are prone to generate extra heat. The longer the stroke length, the greater is the physical impact on the nucleus, and so, the generation of cavitation energy is greater. When the frequency is higher, the impacts per unit time is more and the physical impact is greater.
3.2 Power Generation
Power is created by an interaction between frequency and stroke length.
W. J. Fishkind
Director Fishkind, Bakewell, Maltzman
Eye Care and Surgery Center
Tucson, Arizona, USA
3.3.1 Tuning
The central processing unit (CPU) of modern phaco machines recognizes the phaco needle when it passes into different intraocular media. It does this by turning the driver piezo crystals, momentarily, into receiving crystals. The system is most efficient when it is operating
J. L. Alió, I. H. Fine (eds.), Minimizing Incisions and Maximizing Outcomes in Cataract Surgery, |
37 |
DOI: 10.1007/978-3-642-02862-5_3, © Springer-Verlag Berlin Heidelberg 2010 |
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