- •Contents
- •General Introduction
- •Objectives
- •Introduction
- •1 The Science of Refractive Surgery
- •Corneal Optics
- •Refractive Error: Optical Principles and Wavefront Analysis
- •Measurement of Wavefront Aberrations and Graphical Representations
- •Lower-Order Aberrations
- •Higher-Order Aberrations
- •Corneal Biomechanics
- •Corneal Imaging for Keratorefractive Surgery
- •Corneal Topography
- •Corneal Tomography
- •Indications for Corneal Imaging in Refractive Surgery
- •The Role of Corneal Topography in Refractive Surgery
- •Corneal Effects of Keratorefractive Surgery
- •Incisional Techniques
- •Tissue Addition or Subtraction Techniques
- •Alloplastic Material Addition Techniques
- •Collagen Shrinkage Techniques
- •Laser Biophysics
- •Laser–Tissue Interactions
- •Fundamentals of Excimer Laser Photoablation
- •Types of Photoablating Lasers
- •Corneal Wound Healing
- •2 Patient Evaluation
- •Patient History
- •Patient Expectations
- •Social History
- •Medical History
- •Pertinent Ocular History
- •Patient Age, Presbyopia, and Monovision
- •Examination
- •Uncorrected Visual Acuity and Manifest and Cycloplegic Refraction
- •Pupillary Examination
- •Ocular Motility, Confrontation Fields, and Ocular Anatomy
- •Intraocular Pressure
- •Slit-Lamp Examination
- •Dilated Fundus Examination
- •Ancillary Tests
- •Corneal Topography
- •Pachymetry
- •Wavefront Analysis
- •Calculation of Residual Stromal Bed Thickness After LASIK
- •Discussion of Findings and Informed Consent
- •3 Incisional Corneal Surgery
- •Incisional Correction of Myopia
- •Radial Keratotomy in the United States
- •Incisional Correction of Astigmatism
- •Coupling
- •Arcuate Keratotomy and Limbal Relaxing Incisions
- •Instrumentation
- •Surgical Techniques
- •Outcomes
- •Complications
- •Ocular Surgery After Arcuate Keratotomy and Limbal Relaxing Incisions
- •4 Onlays and Inlays
- •Keratophakia
- •Homoplastic Corneal Inlays
- •Alloplastic Corneal Inlays
- •Epikeratoplasty
- •Intrastromal Corneal Ring Segments
- •Background
- •Instrumentation
- •Technique
- •Outcomes
- •Intacs and Keratoconus
- •One or Two Intacs Segments?
- •Complications
- •Ectasia After LASIK
- •Uses for Intrastromal Corneal Ring Segments After LASIK
- •Orthokeratology
- •5 Photoablation: Techniques and Outcomes
- •Excimer Laser
- •Background
- •Surface Ablation
- •LASIK
- •Wavefront-Optimized and Wavefront-Guided Ablations
- •Patient Selection for Photoablation
- •Special Considerations for Surface Ablation
- •Special Considerations for LASIK
- •Surgical Technique for Photoablation
- •Calibration of the Excimer Laser
- •Preoperative Planning and Laser Programming
- •Preoperative Preparation of the Patient
- •Preparation of the Bowman Layer or Stromal Bed for Excimer Ablation
- •Application of Laser Treatment
- •Immediate Postablation Measures
- •Postoperative Care
- •Refractive Outcomes
- •Outcomes for Myopia
- •Outcomes for Hyperopia
- •Wavefront-Guided and Wavefront-Optimized Treatment Outcomes for Myopia and Hyperopia
- •Re-treatment (Enhancements)
- •6 Photoablation: Complications and Adverse Effects
- •General Complications Related to Laser Ablation
- •Overcorrection
- •Undercorrection
- •Optical Aberrations
- •Central Islands
- •Decentered Ablations
- •Corticosteroid-Induced Complications
- •Central Toxic Keratopathy
- •Infectious Keratitis
- •Complications Unique to Surface Ablation
- •Persistent Epithelial Defects
- •Sterile Infiltrates
- •Corneal Haze
- •Complications Unique to LASIK
- •Microkeratome Complications
- •Epithelial Sloughing or Defects
- •Flap Striae
- •Traumatic Flap Dislocation
- •LASIK-Interface Complications
- •Visual Disturbances Related to Femtosecond Laser LASIK Flaps
- •Ectasia
- •Rare Complications
- •7 Collagen Shrinkage and Crosslinking Procedures
- •Collagen Shrinkage
- •History
- •Laser Thermokeratoplasty
- •Conductive Keratoplasty
- •Collagen Crosslinking
- •8 Intraocular Refractive Surgery
- •Phakic Intraocular Lenses
- •Background
- •Advantages
- •Disadvantages
- •Patient Selection
- •Surgical Technique
- •Outcomes
- •Complications
- •Refractive Lens Exchange
- •Patient Selection
- •Surgical Planning and Technique
- •IOL Power Calculations in Refractive Lens Exchange
- •Complications
- •Advantages
- •Disadvantages
- •Monofocal Intraocular Lenses
- •Toric Intraocular Lenses
- •Patient Selection
- •Planning and Surgical Technique
- •Outcomes
- •Complications Specific to Toric IOLs
- •Light-Adjustable Intraocular Lenses
- •Accommodating Intraocular Lenses
- •Multifocal Intraocular Lenses
- •Patient Selection
- •Surgical Technique
- •Outcomes
- •Adverse Effects, Complications, and Patient Dissatisfaction with Multifocal IOLs
- •Bioptics
- •Introduction
- •Theories of Accommodation
- •Nonaccommodative Treatment of Presbyopia
- •Monovision
- •Conductive Keratoplasty
- •Multifocal IOL Implants
- •Custom or Multifocal Ablations
- •Corneal Intrastromal Femtosecond Laser Treatment
- •Corneal Inlays
- •Accommodative Treatment of Presbyopia
- •Scleral Surgery
- •Femtosecond Lens Relaxation
- •Accommodating IOLs
- •Other IOL Innovations on the Horizon
- •10 Refractive Surgery in Ocular and Systemic Disease
- •Introduction
- •Ocular Conditions
- •Ocular Surface Disease
- •Herpesvirus Infection
- •Keratoconus
- •Post–Penetrating Keratoplasty
- •Ocular Hypertension and Glaucoma
- •Retinal Disease
- •Amblyopia and Strabismus in Adults and Children
- •Systemic Conditions
- •Human Immunodeficiency Virus Infection
- •Diabetes Mellitus
- •Connective Tissue and Autoimmune Diseases
- •11 Considerations After Refractive Surgery
- •IOL Calculations After Refractive Surgery
- •Eyes With No Preoperative Information
- •The ASCRS Online Post-Refractive IOL Power Calculator
- •Retinal Detachment Repair After LASIK
- •Corneal Transplantation After Refractive Surgery
- •Contact Lens Use After Refractive Surgery
- •Indications
- •General Principles
- •Contact Lenses After Radial Keratotomy
- •Contact Lenses After Surface Ablation
- •Contact Lenses After LASIK
- •Glaucoma After Refractive Surgery
- •12 International Perspectives in Refractive Surgery
- •Introduction
- •Global Estimates of Refractive Surgery
- •International Trends in Refractive Surgery
- •Basic Texts
- •Related Academy Materials
- •Requesting Continuing Medical Education Credit
American Society of Cataract and Refractive Surgery.)
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Shammas HJ. Intraocular lens power calculation in patients with prior refractive surgery. Focal Points: Clinical Modules for Ophthalmologists. San Francisco: American Academy of Ophthalmology; 2013, module 6.
Wang L, Hill WE, Koch DD. Evaluation of intraocular lens power prediction methods using the American Society of Cataract and Refractive Surgeons PostKeratorefractive Intraocular Lens Power Calculator. J Cataract Refract Surg. 2010;36(9):1466–1473.
Retinal Detachment Repair After LASIK
Even if the eyes of patients with high myopia become emmetropic as a result of refractive surgery, these patients need to be informed that their eyes remain at increased risk of retinal detachment. For this reason, the vitreoretinal surgeon should ask about prior refractive surgery. Eyes undergoing retinal detachment repair after LASIK are prone to flap problems, including flap dehiscence, microstriae, and macrostriae. The surgeon may find it helpful to mark the edge of the flap prior to surgery to aid in flap replacement in case the flap is dislodged. The risk of flap problems increases dramatically if the epithelium is debrided during the retinal detachment repair. If flap dehiscence occurs, the flap should be carefully repositioned and the interface irrigated. A bandage soft contact lens may be placed at the end of the procedure.
Postoperatively, the patient should be observed closely for signs of flap problems such as epithelial ingrowth and diffuse lamellar keratitis, especially if an epithelial defect was present on the flap. After retinal detachment repair, the intraocular pressure (IOP) needs to be monitored, especially when an intraocular gas bubble is used, keeping in mind that IOP measurements may read falsely low after refractive surgery because of corneal thinning. Additionally, elevated IOP can cause a diffuse lamellar keratitis–like picture or even a fluid cleft between the flap and the stroma, resulting in a misleading, extremely low IOP measurement. These problems are discussed in greater detail later in the chapter in the section Glaucoma After Refractive Surgery.
Qin B, Huang L, Zeng J, Hu J. Retinal detachment after laser in situ keratomileusis in myopic eyes. Am J Ophthalmol. 2007;144(6):921–923. Epub 2007 Oct 4. Wirbelauer C, Pham DT. Imaging interface fluid after laser in situ keratomileusis with corneal optical coherence tomography. J Cataract Refract Surg.
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Corneal Transplantation After Refractive Surgery
Corneal transplantation is occasionally required after refractive surgery. Reasons for needing a corneal graft after refractive surgery include significant corneal scarring, irregular astigmatism, corneal ectasia, and corneal edema. Issues unrelated to refractive surgery, such as trauma or corneal edema after cataract surgery, can also necessitate corneal transplant surgery. Each type of refractive surgical procedure is unique in the reasons a graft may be required and in ways to avoid problems with the corneal transplant. Corneal transplantation is discussed in greater detail in BCSC Section 8,
External Disease and Cornea.
