Index

Mastering the Techniques of IOL Power Calculations Ashok Garg, JT Lin, Robert Latkany, Jerome Bovet

SECTION 1: PRELIMINARY CONSIDERATIONS AND VARIOUS IOL POWER CALCULATION FORMULAS AND BASICS
CHAPTER 1:Schematic Eye
- INTRODUCTION
- REFRACTION BY COMBINATION OF LENSES
- GAUSS'S THEOREM
- SCHEMATIC EYE OF GULLSTRAND
- LISTING'S EYE
- DONDER'S REDUCED EYE
CHAPTER 2:A-scan Biometry
- INTRODUCTION
- AXIAL LENGTH MEASUREMENT
- KERATOMETRIC MEASUREMENTS
- IOL FORMULA
- RELATION OF EQUIPMENT TO SPECIFIC FORMULAE
- TARGETING IOL POSTOPERATIVE REFRACTION
  - Monocular Correction
  - Binocular Correction
- FACTORS AFFECTING ACCURACY OF IOL POWER CALCULATION
- PSEUDOPHAKIC LASIK
CHAPTER 3:Corneal Topography
- INTRODUCTION
- CORNEA
- KERATOMETRY
- KERATOSCOPY
- COMPUTERIZED VIDEOKERATOGRAPHY
- NORMAL CORNEA
- READING A CORNEAL TOPOGRAPHY
- CORNEAL DISEASES
- CONTACT LENS-INDUCED WARPAGE
- RADIAL KERATOTOMY
- LASIK
- REGRESSION AFTER LASIK
  - Myopia
  - Hyperopia
- RE-LASIK
- COMPLICATIONS OF LASIK
  - Central Islands
  - Decentered Ablation
- CATARACT SURGERY
- SUMMARY
CHAPTER 4:Optical Corneal Tomography
CHAPTER 5:Optical Biometry with IOL Master (Partial Coherence Interferometry)
- INTRODUCTION
- IOL MASTER
  - Technique
    - Ideal Axial Length Recording
- INFERENCE
CHAPTER 6:Anterior Chamber Depth in IOL Power Estimation
- INTRODUCTION
CHAPTER 7:How to Calculate the Constant A
- INTRODUCTION
- OPTICS OF THE THIN PLUS LENS1
- THE TWO-LENS SYSTEM
- IOL FORMULA2,3
- CONCLUSION
CHAPTER 8:Axial Length Dependence of IOL Constants
- INTRODUCTION
- MATERIAL AND METHODS
  - Model Calculations
  - Clinical Data
- RESULTS
  - Model Calculations
  - Clinical Results
- DISCUSSION
- CONCLUSION
- ACKNOWLEDGEMENT
CHAPTER 9:IOL Calculations: When, How and Which?
- IOL MASTER PHYSICS
- IOL POWER CALCULATION FORMULAE: IOL MASTER BASICS, APPLICATION AND FALLACIES
  - Background
  - Theoretical Formulae1
- COMPARISON IMMERSION ULTRASOUND BIOMETRY (IUS) VS PARTIAL COHERENCE INTERFEROMETRY (PCI/OCB)
CHAPTER 10:How to Measure a Correct Central Keratometric Reading for IOL Power Calculation After LASIK Surgery?
- INTRODUCTION
- ERRORS IN IOL POWER CALCULATION
- METHODS TO MEASURE KERATOMETRIC DIOPTERS
- METHODS TO IMPROVE THE PREDICTION OF INTRAOCULAR POWER
- CONCLUSION
CHAPTER 11:An Update on IOL Power Calculation Formulas
- INTRODUCTION
- IOL POWER FORMULAS
  - Theoretical Formulas
  - Regression Formulas
- THE ESTIMATED IOL POSITION (ELP)
- ACCURACY OF IOL POWER CALCULATION
- THE NEW GENERATION FORMULAS
- IOL POWER IN APHAKIC EYE
- IOL POWER IN PHAKIA AND PIGGYBACK-IOL
- PIGGYBACK IOL POWER
- ACCOMMODATING IOL (AIOL)
- CONCLUSION
CHAPTER 12:The New IOL Formulas based on Gaussian Optics
- INTRODUCTION
- TWO OPTICS FORMULAS (APHAKIC EYE)
- THE IOL POWER IN APHAKIA
- CONVERSION FUNCTION (CF)
  - Clinical Application
- THE REVISED Z2 FORMULAS
  - Three-optics IOL System
- PIGGYBACK IOL-POWER
- COMPARISON OF 2 AND 3-OPTICS
- UNIFIED EFFECTIVE FORMULA
  - Error Analysis
- SPECTACLE POWER AND HOLLADAY FORMULA
  - Case (1)
  - Case (2)
- CONCLUSION
- APPENDIX
  - 3-optics IOL
CHAPTER 13:Classical vs Modern Formulas for Estimated Lens Position (ELP)
- INTRODUCTION
- APHAKIC VERSUS PHAKIC IOL
- THE ESTIMATED LENS POSITION (ELP)
- NONLINEAR GAUSSIAN-FORMULA
  - The Classical Formula
  - The Lin Formula
- TRIPLE OPTIMIZATION
- NONLINER OPTIMIZATION
- CONCLUSION
CHAPTER 14:IOL Power Calculations
- INTRODUCTION
- BIOMETRY
- FORMULAS
- CLINICAL VARIABLES
- CONCLUSION
CHAPTER 15:The Theoretical Summary of IOL Formulas
- INTRODUCTION
- IOL POWER IN APHAKIA (2-OPTICS)
- CONVERSION FUNCTION (CF)
  - Conversion to Spectacle Power
  - IOL-Power (P) vs Spectacle Power (Ds)
- THREE-OPTICS IOL SYSTEM
- ACCOMMODATIVE IOL
  - Two-optics Formulas (Lin, 2005)
  - Three-optics Formulas (Lin. 2006)
- DESIGN OF ASPHERICAL IOLs
- IOL FOR PEDIATRIC EYES
- CONCLUSION
CHAPTER 16:Error Analysis of IOL Power Calculations
- INTRODUCTION
- SUMMARY AND NOTATIONS
- NOTATIONS
- CORNEAL-POWER ERRORS
- IOL POSITION ERROR
- AXIAL LENGTH ERROR
- MIS-LABELING ERROR
- CONCLUSION
CHAPTER 17:The Basics of Accommodating IOLs
- INTRODUCTION
- CATEGORIES OF AIOL
- THE BASIC PRINCIPLES
  - Single-optics IOL (referred to Fig. 17.2)
  - Dual-optics IOL (Referred to Fig. 17.4)
- DISCUSSION OF SINGLE-OPTICS IOL
- THREE-OPTICS SYSTEM (IN PHAKIA)
- OPTIMAL IOL DESIGN
- CONCLUSION
- APPENDIX (SINGLE-OPTICS IOL)
CHAPTER 18:IOL Calculation in Long and Short Eyes
- INTRODUCTION
- LONG AND SHORT EYES
  - Short Eyes
  - Long Eyes
- IOL POWER FORMULAS
- AXIAL LENGTH DEPENDENCE OF PREDICTION ERROR
- CONCLUSION
- ACKNOWLEDGEMENT
CHAPTER 19:Customization of IOL Formulas
- INTRODUCTION
- CONCLUSION
- ACKNOWLEDGEMENT
SECTION 2: IOL POWER CALCULATIONS IN CATARACT SURGERY
CHAPTER 20:Intraocular Lens Power Selection for Children
- CORE MESSAGE
- IOL POWER SELECTION METHOD
- SUMMARY
- TAKE HOME PEARLS
CHAPTER 21:Age Dependent IOL Power Calculations for Pediatric Patients
- INTRODUCTION
- REFRACTION POWER OF APHAKIC EYES
  - Age 3 and up
  - Age 0 to 3
- PSEUDOPHAKIC EYE (AGE 0 TO 3)
- THE LIN'S DOUBLE-RATE (M AND N)
  - Definitions
- CUSTOMIZED IOL POWER
  - The Adjusted IOL-power
  - Adjusted Factors
- CONCLUSION
CHAPTER 22:History & Method of Intraocular Lens Power Calculation for Cataract Extraction Surgery after Corneal Refractive Surgery
- INTRODUCTION
  - Myopic Treatments
  - Hyperopic Treatments
- THE CLINICAL HISTORY METHOD
- CONCLUSION
CHAPTER 23:Intraocular Lens Power Calculations in Phaco and Microphaco
- INTRODUCTION
- A SCAN BIOMETRY
- IOL MASTER
  - Technique
    - Ideal Axial Length Recording
- FORMULAS FOR CALCULATING IOL POWER
- ACCURACY OF IOL POWER CALCULATION
- CONCLUSION
CHAPTER 24:Intraocular Lens Power Calculations for High Myopia
- INTRODUCTION
- INTRAOCULAR LENS POWER CALCULATION FORMULAS
- PREOPERATIVE BIOMETRY
- SATISFACTORY POSTOPERATIVE REFRACTIVE STATUS
- REFRACTIVE INDEX OF CORNEA AND A-CONSTANT
- CONCLUSION
CHAPTER 25:Accuracy of Intraocular Lens Power Calculation in Bimanual Microphacoemulsification
- INTRODUCTION
- KERATOMETRY
- AXIAL LENGTH MEASUREMENTS
- IOL CONSTANT OPTIMIZATION
- SURGICAL TECHNIQUE
- PATIENTS AND METHODS
- SURGICAL TECHNIQUE
- RESULTS
- DISCUSSION
CHAPTER 26:Clinical Outcomes of Cataract Surgery after Previous Refractive Surgery
- INTRODUCTION
- DELAY OF CATARACT SURGERY AFTER PREVIOUS REFRACTIVE CORNEAL SURGERY
- TYPE OF CATARACT AFTER REFRACTIVE SURGERY
- PATIENT'S AGE AT TIME OF CATARACT SURGERY
- LITERATURE: PREVALENCE OF CATARACT IN MYOPIA AND MANIFESTATION OF CATARACT IN MYOPIA
- A CASE REPORT
- SUMMARY
SECTION 3: IOL POWER CALCULATIONS IN REFRACTIVE SURGERY (CORNEAL AND LENTICULAR REFRACTIVE SURGERY)
CHAPTER 27:IOL Power Calculations: A Topographic Method
- INTRODUCTION
- POST CORNEAL SURGERY SHAPE
- FORMULAS FOR IOL CALCULATION
- TOPOGRAPHIC METHOD
- EXAMPLES FOR TOPOGRAPHIC METHOD
  - After RK Radial Keratometry
  - After LASIK
- CONCLUSION
CHAPTER 28:IOL Power Calculation in Post-hyperopic Presby-LASIK Cataract: Preliminary Results
- INTRODUCTION
- CONCLUSION
CHAPTER 29:Comparison of Methods for IOL Power Calculation after Incisional & Photoablative Refractive Surgery
- CORNEAL POWER AFTER KERATOREFRACTIVE SURGERY
- THE EFFECTIVE LENS POSITION: ANOTHER SOURCE OF ERROR
- INTRAOCULAR LENS POWER CALCULATION AFTER REFRACTIVE CORNEAL SURGERY
- THE CAMELLIN-CALOSSI FORMULA
  - Surgery
    - Incisional Refractive Surgery
    - Laser Ablative Refractive Surgery
  - Clinical Data
CHAPTER 30:IOL Power Calculations after Corneal Refractive Surgery
- INTRODUCTION
- STRATEGIES TO BE USED WHEN PRIOR DATA IS AVAILABLE
- STRATEGIES TO BE USED WHEN PRIOR DATA IS NOT AVAILABLE
CHAPTER 31:The Latkany Regression Formula for Intraocular Lens Calculations after Myopic Refractive Surgery
- INTRODUCTION
- INTRAOCULAR LENS POWER CALCULATION
- PROSPECTIVE ANALYSIS OF LATKANY REGRESSION FORMULA
CHAPTER 32:The Latkany Regression Formula for Intraocular Lens Calculations after Hyperopic Refractive Surgery
- INTRODUCTION
- EXAMPLE
CHAPTER 33:Which IOL Formula to Use after Refractive Surgery
- INTRODUCTION
- HISTORY DERIVED METHOD
- ESTIMATE TRUE CORNEAL POWER WITHOUT HISTORY CL METHOD
  - Trial Hard Contact Lens Method
- ESTIMATE TRUE CORNEAL POWER WITHOUT HISTORY KOCH/MALONEY TOPO CENTRAL K (CENTRAL KERATOSCOPE READING)13,14
- FUDGE THE TARGET IOL POWER WITHOUT HISTORY MACKOOL SECONDARY IOL
- USING A MODIFIED HOFFER Q FORMULA FOR IOL POWER CALCULATIONS AFTER LASIK15,16
- THE CONSENSUS-K TECHNIQUE FROM JB. RANDLEMAN17,18
- SUMMARY
CHAPTER 34:Intraocular Lens Power Calculation after Advanced Surface Ablations (ASA)
- INTRODUCTION
- PROPOSED METHODS
- CONCLUSION
CHAPTER 35:The Mathematics of LASIK
- INTRODUCTION
- REFRACTION POWER
- REFRACTIVE ERROR (D)
- LASIK ABLATION RATE
- BIFOCAL (PRESBY-LASIK)
- ASPHERICITY COMPARISON
- MIXED ASTIGMATISM
- LASIK ABLATION NOMOGRAM
- SURFACE ABERRATION
- CONCLUSION
CHAPTER 36:Preoperative Evaluation of the Anterior Chamber for Phakic IOLs with the AC OCT
- INTRODUCTION
  - Optical Coherence Tomography Technology for the Anterior Chamber
  - Interest of the AC OCT and the Study of Accommodation when Implanting Phakic IOLs
- SUMMARY
CHAPTER 37:Biometry for Refractive Lens Surgery
- INTRODUCTION
- AXIAL LENGTH MEASUREMENTS
- SURGICAL OUTCOMES ASSESSMENT
- KERATOMETRY AFTER KERATOREFRACTIVE SURGERY
CHAPTER 38:IOL Power Calculations in Phakic IOLs
- INTRODUCTION
- PRL POWER CALCULATION
- CLINICAL RULES
CHAPTER 39:Raytracing Analysis of Accommodating IOL
- INTRODUCTION
- THE METHODS OF ACCOMMODATION
- REFERENCES
- APPENDIX 1
  - Ray-tracing analysis of pseudophakic eyes
- APPENDIX 2
  - Ray-tracing analysis of pseudophakic eyes with piggyback IOL or double-optic IOL
CHAPTER 40:Analysis of Dual-optics Accommodating IOL
- INTRODUCTION
- THE ACCOMMODATING RATE (M)
- PERFORMANCE AND CONFIGURATIONS
  - Definition
    - Example #1 (Fig. 40.3A)
    - Example # 2 (Figs 40.3B and C)
  - Maximal Accommodation
- SOURCE ABERRATION
- CONCLUSION
- APPENDIX: DERIVATION OF LIN'S M-FORMULA
  - Case (1): Front Optics Mobile
  - Case (2): Back Optics Mobile
CHAPTER 41:Aspherical IOL Analysis
- INTRODUCTION
- ASPHERICA PROFILE
- PREDICTION OF CORNEAL ASPHERICITY
  - Example # 1
  - Example # 2
- CENTRAL ABLATION DEPTH
- POSITIVE CYLINDER FOR MIXED ASTIGMATISM
- EFFECTIVE ZONE SIZE
- SURFACE ABERRATION
- APPLICATIONS
- COMPARISON OF CENTRAL ABLATION DEPTHS
- COMPARISON OF THEORY AND MEASUREMENTS
- CONCLUSION
SECTION 4: MISCELLANEOUS (RECENT ADVANCES AND IOL POWER CALCULATIONS IN DIFFICULT SITUATIONS)
CHAPTER 42:Determining Corneal Power for Intraocular Lens Calculation in Patients with Corneal Scarring and Irregular Astigmatism
- INTRODUCTION
- TWO CASES OF IOL CALCULATIONS IN EYES WITH CENTRAL CORNEAL SCARS
- CONCLUSION
CHAPTER 43:IOL Calculation in Hyperopes
- INTRODUCTION
- MATERIAL AND METHODS
- RESULTS
- DISCUSSION
- CONCLUSION
CHAPTER 44:Consistent IOL Calculation in Normal and Odd Eyes with the Raytracing Program OKULIX
- ABSTRACT
- PRINCIPLE
- CORNEAL RADII
- IOL POSITION
- CLINICAL RESULTS IN “NORMAL” EYES
- CLINICAL RESULTS AFTER CORNEAL SURGERY
- DISCUSSION
CHAPTER 45:A-scan in Difficult Situations
- INTRODUCTION
- KERATOMETRY IN CORNEAL SCARRING/LACERATIONS
- POSTREFRACTIVE SURGERY IOL CALCULATION
- HARD CONTACT LENS METHOD
- REFRACTIVE HISTORY METHOD
- ADJUSTING INTRAOCULAR LENS POWER FOR SULCUS FIXATION
- INTRAOCULAR LENS POWER CALCULATIONS IN PATIENTS WITH EXTREME MYOPIA
- INTRAOCULAR LENS POWER CALCULATION FOR LENS EXCHANGE
- METHODS OF ESTIMATING CORNEAL REFRACTIVE POWER AFTER HYPEROPIC LASER IN SITU KERATOMILEUSIS
- CHANGES IN KERATOMETRIC CORNEAL POWER AND REFRACTIVE ERROR AFTER LASER THERMAL KERATOPLASTY
- REFRACTIVE CHANGES IN PEDIATRIC PSEUDOPHAKIA
- INTRAOCULAR LENS POWER CALCULATION AFTER MACULAR HOLE SURGERY
- AXIAL LENGTH MEASUREMENT AND ASTEROID HYALOSIS
- BILATERAL MICROCORNEA AND UNILATERAL MACROPHTHALMIA RESULTING IN INCORRECT INTRAOCULAR LENS SELECTION
CHAPTER 46:Management of Refractive Surprises after Cataract Surgery
- INTRODUCTION
- INTRAOCULAR LENS EXCHANGE
- SECONDARY PIGGYBACK INTRAOCULAR LENS IMPLANTATION
- CORNEAL REFRACTIVE SURGERY
- CASE REPORTS
  - Case 1
  - Case 2
CHAPTER 47:Intraocular Lens Power Calculation in the High Myopic Eye
- INTRODUCTION
- THE FORMULAS OF IOL POWER CALCULATION
- AXIAL LENGTH MEASUREMENT
  - A-scan and B-scan Ultrasonography
  - IOL-Master
- IOL POWER CALCULATION OF EYES AFTER CORNEAL REFRACTIVE SURGERY
CHAPTER 48:Calculation of Intraocular Lens Power in Cataract with Silicone Oil Eyes
- INTRODUCTION
CHAPTER 49:Intraoperative IOL Power Calculation
- INTRODUCTION
- OPTICAL AND PHYSICAL BASIS
- NO AL- NO KM'S
- INTRAOPERATIVE FACTORS
- REFRACTIVE METHODS
- FUNDOSCOPY
- SPECIAL CASES
- CONCLUSION
CHAPTER 50:ZEMAX Raytracing Method for Accommodative IOL
- INTRODUCTION
- THE ACCOMMODATING RATE (M)
  - Mobile Back-optics Case
  - Mobile Front-optics Case
- ZEMAX RAYTRACING METHOD
- RESULTS
- CONCLUSION
- APPENDIX: DERIVATION OF LIN'S M-FORMULA
  - Case (1): Back Optics Mobile
  - Case (2): Front Optics Mobile
CHAPTER 51:Problems of IOL Power Calculation in Pediatric Cataract Surgery
- INTRODUCTION
- NORMAL EYE DEVELOPMENT
- REFRACTIVE CHANGES OF THE EYE AFTER LENS REMOVAL AND IOL IMPLANTATION
- POSTOPERATIVE REFRACTIVE GOAL IN CHILDREN
- PRACTICAL GUIDELINES IN IOL CALCULATION IN CHILDREN
- CONCLUSION
CHAPTER 52:Intraocular Lens Calculation after Prior Refractive Surgery
- INTRODUCTION
- BIPHAKIC EYES (PHAKIC EYE WITH A PHAKIC INTRAOCULAR LENS)
- CORNEAL REFRACTIVE EYES
- HISTORY OF SOLUTIONS
  - Methods To Estimate True Postoperative Corneal Power
    - Those Needing Clinical History
    - Those Not Needing Clinical History
  - Methods to Adjust/Calculate the Target Intraocular Lens Power
    - Those Needing Clinical History
    - Those Not Needing Clinical History
- IMPORTANT THINGS TO KEEP IN MIND
- WHAT FORMULA TO USE?
- HOW TO HANDLE PROBLEMS AND ERRORS?
- CONCLUSION
CHAPTER 53:Cataract Surgery: Calculating the IOL Power in Case of Anisometropia
- INTRODUCTION
- A COMPREHENSIVE APPROACH TO ANISEIKONIA
- DISCUSSION
CHAPTER 54:Review of IOL Power Calculation: A Theoretical Analysis of Proposed Formulas
- INTRODUCTION
- DEFINITIONS BASED ON THE BINKHORST FORMULA
- DISCUSSION
- CONCLUSION
CHAPTER 55:IOL Power Calculation for Cornea Triple and Penetrating Keratoplasty with IOL Exchange
- INTRODUCTION
- MULTI STEP PROCEDURE
CHAPTER 56:IOL Power Calculations in Eyes with Irregular Corneas
- INTRODUCTION
- CORNEAL POWER CALCULATION
- KERATOMETRY PROBLEMS
- FUTURE

INDEX

TOC
Index

Chapter Notes