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Файл:Ординатура / Офтальмология / Учебные материалы / Vitreoretinal Surgery Second Edition Springer.pdf
X
- •Preface
- •Contents
- •1.1.1 The Vitreous
- •1.1.1.1 Embryology
- •1.1.1.2 The Anatomy
- •1.1.1.3 Anatomical Attachments of the Vitreous to the Surrounding Structures
- •1.1.2 The Retina
- •1.1.2.1 Embryology
- •1.1.2.2 Anatomy
- •Retinal Pigment Epithelium (RPE)
- •Photoreceptor Layer
- •Intermediary Neurones
- •Ganglion Cells
- •Retinal Blood Vessels
- •Other Fundal Structures
- •1.1.3 The Physiology of the Vitreous
- •1.2 Clinical Examination and Investigation
- •1.2.1 Using the Database
- •1.2.2 Examination of the Eye
- •1.2.2.1 Examination Technique
- •Visual Acuity
- •1.2.2.2 The Slit Lamp
- •1.2.2.3 Binocular Indirect Ophthalmoscope
- •1.2.2.4 Using the Indenter
- •1.2.2.5 Ultrasonography
- •Posterior Vitreous Detachment (PVD)
- •Retinal Tear
- •Retinal Detachment
- •Subretinal Haemorrhage
- •Retinoschisis
- •Choroidal Elevation
- •Trauma
- •1.2.2.6 Optical Coherence Tomography
- •Time-Domain OCT
- •Colour Coding
- •Frequency-Domain OCT
- •Full-Field OCT
- •Scan Resolution
- •Images and Measurements
- •Performing the Scan
- •Macular Scan Patterns
- •Central Retinal Thickness
- •Inner Segment and Outer Segment Junction and External Limiting Membrane
- •1.2.3 Subjective Tests
- •1.2.4 The Preoperative Assessment
- •1.3 Summary
- •References
- •2: Introduction to Vitreoretinal Surgery
- •2.1 Introduction
- •2.2 Choice of Anaesthesia
- •2.3 Pars Plana Vitrectomy
- •2.3.1 Sclerotomies
- •2.3.2 Where to Place the Sclerotomies
- •2.3.3 Securing the Infusion Cannula
- •2.3.4 Checking the Infusion
- •2.3.6 The Superior Sclerotomies
- •2.3.6.1 Where to Place
- •2.3.7 Checking the View
- •2.3.8 The Independent Viewing System
- •2.3.9 Removing the Vitreous
- •2.4 Vitrectomy Cutters
- •2.5 Handling the Light Pipe
- •2.6 Use of Sclerotomy Plugs
- •2.7 The Internal Search
- •2.8 Endolaser
- •2.9 Using a Contact Lens
- •2.10 Maintaining a View
- •2.10.1 Microscope
- •2.10.3 Cornea
- •2.10.4 Blood in the Anterior Chamber
- •2.10.5 Condensation on an Intraocular Lens Implant
- •2.10.6 Cataract Formation
- •2.10.7 Pupillary Dilation
- •2.11 Closing
- •2.12 Peroperative Complications
- •2.12.1 Iatrogenic Breaks
- •2.12.1.1 Causes
- •2.12.2 Choroidal Haemorrhage
- •2.12.3 Haemorrhage from Retinal or Other Blood Vessels
- •2.12.4 Lens Touch
- •2.12.5 Hypotony
- •2.13 Postoperative Complications
- •2.13.1 Cataract
- •2.13.2 Endophthalmitis
- •2.13.3 Corneal Changes
- •2.13.4 Choroidal Haemorrhage
- •2.13.5 Raised Intraocular Pressure
- •2.13.6 Retinal Breaks and RRD
- •2.13.7 Hypotony
- •2.13.8 Scleritis
- •2.13.9 Sympathetic Uveitis
- •2.14 Adjustments for 20 Gauge Vitrectomy
- •2.14.1 Construction of Superior Sclerotomies
- •2.14.2 Priming
- •2.14.3 Self-Sealing Sclerotomies
- •2.15 Adjustments for 23 and 25 Gauge Vitrectomy
- •2.15.1 Instrumentation
- •2.15.2 Surgical Technique
- •2.15.2.1 Vitrectomy Technique
- •2.15.3 Flexibility
- •2.15.4 Indentation
- •2.15.5 Flow Rates
- •2.15.6 Trochar Internal Protrusion
- •2.15.7 Silicone Oil
- •2.16 Complications
- •2.16.1 Peroperative
- •2.16.1.1 Extrusion of the Trochar on Removal of Instrumentation
- •2.16.1.2 Conjunctival Chemosis
- •2.16.1.3 Hypotony
- •2.16.1.4 Endophthalmitis
- •2.16.2 Postoperative Retinal Break Formation
- •2.17 Advantages and Disadvantages of 23 and 25 G Systems
- •2.18 Combined Cataract Extraction and PPV
- •2.18.1 How to Decide Whether to Perform Combined Surgery
- •2.18.1.1 Accommodation
- •2.19 Biometry
- •2.20 Chandelier Systems and Bimanual Surgery
- •2.20.1 Possible Complications
- •2.21 Dyes
- •2.22 Intravitreal Injections
- •2.22.1 Injection Medications
- •2.23 Slow Release Preparations
- •2.24 Summary
- •References
- •3: Principles of Internal Tamponade
- •3.1 Gases
- •3.1.1 Principles
- •3.1.1.1 Properties
- •3.1.1.2 A Safe Method for Drawing Up Gas
- •3.1.2 Complications
- •3.1.2.1 Vision
- •3.1.2.2 Refraction
- •3.1.2.3 Cataract
- •3.1.2.5 Loss of the Gas Bubble
- •3.1.2.6 Gas in the Wrong Place
- •3.1.3 Important Postoperative Information
- •3.1.3.1 Flying or Travel to High Altitude
- •3.1.3.2 General Anaesthesia
- •3.2 Silicone Oil
- •3.2.1 Properties
- •3.2.3 Complications of Silicone Oil
- •3.2.3.1 Refractive Changes
- •3.2.3.2 Cataract
- •3.2.3.5 Cornea
- •3.2.3.6 Macular Toxicity
- •3.2.3.7 Oil in the Wrong Place
- •3.2.3.8 Emulsion
- •3.2.3.9 IOLs
- •3.2.4 Silicone Oil Removal
- •3.2.4.1 Alternative Methods
- •3.2.4.2 Retinal Redetachment Rates After Oil Removal
- •3.2.5 Heavy Silicone Oils
- •3.2.6 Heavy Liquids
- •3.2.7 ‘Light’ Heavy Liquids
- •3.3 Summary
- •References
- •4: Posterior Vitreous Detachment
- •4.1 Introduction
- •4.1.1 Symptoms
- •4.1.1.1 Floaters
- •4.1.1.2 Flashes
- •Introduction
- •Clinical Characteristics
- •4.1.2 Signs
- •4.1.2.1 Detection of PVD
- •4.1.2.2 Shafer’s Sign
- •4.1.2.3 Vitreous Haemorrhage
- •4.1.2.4 Ophthalmoscopy
- •4.1.3 Retinal Tears
- •4.1.3.1 U Tears
- •4.1.3.2 Atrophic Round Holes
- •4.1.3.3 Other Breaks
- •4.1.3.4 Progression to Retinal Detachment
- •4.1.4 Peripheral Retinal Degenerations
- •4.2 Summary
- •References
- •5: Vitreous Haemorrhage
- •5.1 Introduction
- •5.2 Aetiology
- •5.3 Natural History
- •5.4 Erythroclastic Glaucoma
- •5.5 Investigation
- •5.6 Ultrasound
- •5.7 Management
- •5.8 Surgery
- •5.9 Vitrectomy
- •5.10 Summary
- •References
- •6: Rhegmatogenous Retinal Detachment
- •6.1 Introduction
- •6.1.1 Tears with Posterior Vitreous Detachment
- •6.1.2 Breaks Without Posterior Vitreous Detachment
- •6.1.3 Natural History
- •6.1.3.1 Chronic RRD
- •6.1.3.2 Risk to the Other Eye
- •6.2 Clinical Features
- •6.2.1 Anterior Segment Signs
- •6.2.2 Signs in the Vitreous
- •6.2.3 Subretinal Fluid Accumulation
- •6.2.4 Retinal Break Patterns in RRD
- •6.2.5 Macula Off or On
- •6.3 Surgery
- •6.3.1 Flat Retinal Breaks
- •6.3.1.1 Retinopexy
- •6.3.1.2 Cryotherapy
- •6.3.1.3 Cryotherapy in the Clinic Setting
- •6.3.1.4 Laser
- •6.3.1.5 Laser in the Clinic Setting
- •6.3.2 Retinal Detachment
- •6.3.2.1 Principles
- •6.3.2.2 Break Closure
- •6.3.2.3 Relief of Traction
- •6.3.2.4 Alteration of Fluid Currents
- •6.3.2.5 Retinopexy
- •6.3.3 Pars Plana Vitrectomy
- •6.3.3.1 Introduction
- •6.3.3.2 Finding the Breaks
- •6.3.3.4 Draining Subretinal Fluid
- •6.3.3.5 When to Use Heavy Liquids
- •6.3.3.6 Removal of Heavy Liquid
- •6.3.3.7 Choice of Tamponade
- •6.3.3.8 Avoiding Retinal Folds
- •6.3.3.9 Inferior Breaks
- •6.3.3.10 Posterior Breaks
- •6.3.3.11 Multiple Breaks
- •6.3.3.12 Medial Opacities
- •6.3.3.13 Complications
- •6.3.3.14 Surgery for Eyes with No Breaks Found
- •6.3.3.15 Use of 360° Laser or Routine 360° Encirclage
- •6.3.3.16 Posturing
- •6.3.4.1 Operative Stages
- •6.3.4.2 Postoperative Care
- •6.3.4.3 Complications
- •6.3.4.4 Peroperative
- •6.3.4.5 Postoperative
- •6.3.5 Drainage Air Cryotherapy and Explant (DACE)
- •6.3.5.1 Subretinal Fluid (SRF) Drainage
- •6.3.5.2 Air Insertion
- •6.3.5.3 Complications
- •6.3.6 Pneumatic Retinopexy
- •6.3.6.1 Surgical Steps
- •6.3.6.2 Complications
- •6.4 Success Rates
- •6.5 Causes of Failure
- •6.6 Surgery for Redetachment
- •6.7 Secondary Macular Holes
- •6.8 Detachment with Choroidal Effusions
- •6.9 Removal of Explant
- •6.9.1 Diplopia
- •6.9.2 Erosion Through Conjunctiva
- •6.9.3 Infection
- •6.9.4 Cosmesis
- •6.9.5 Irritation
- •6.9.6 Surgery for Removal of the Explant
- •6.10 Summary
- •References
- •7.2 Atrophic Hole RRD with Attached Vitreous
- •7.3 Pseudophakic RRD
- •7.4 Aphakic RRD
- •7.5 Retinal Dialysis
- •7.5.1 Clinical Features
- •7.5.2 Surgery for Retinal Dialysis
- •7.5.2.1 Search
- •7.5.2.2 Cryotherapy
- •7.5.2.3 Marking the Break
- •7.5.2.4 Plombage
- •7.5.2.5 Checking the Indent
- •7.5.3 Complications
- •7.5.4 Giant Retinal Dialysis
- •7.5.5 Dialysis and PVR
- •7.5.6 Par Ciliaris Tear
- •7.6 Giant Retinal Tear
- •7.6.1 Clinical Features
- •7.6.2 Stickler’s Syndrome
- •7.6.3 Surgery for Giant Retinal Tear
- •7.6.3.1 Heavy Liquids
- •7.6.3.2 Retinopexy
- •7.6.3.3 Trans-scleral Illumination Technique
- •7.6.3.4 Silicone Oil Insertion
- •7.6.3.5 Choice of Endotamponade
- •7.6.3.6 Success Rates
- •7.6.3.7 Removal of the Silicone Oil
- •7.6.3.8 The Other Eye
- •7.7 Retinal Detachment in High Myopes
- •7.7.1 Clinical Features
- •7.7.2 Surgery
- •7.8.1 Clinical Features
- •7.8.1.1 Infantile Retinoschisis
- •7.8.1.2 Senile Retinoschisis
- •7.8.1.4 Retinal Detachment in Retinoschisis
- •7.8.2 Surgery
- •7.9 Juvenile Retinal Detachment
- •7.10 Atopic Dermatitis
- •7.11 Refractive Surgery
- •7.12 Congenital Cataract
- •7.13 Others
- •7.14 Summary
- •References
- •8: Proliferative Vitreoretinopathy
- •8.1 Introduction
- •8.2 Pathogenesis
- •8.3 Clinical Features
- •8.3.1 Introduction
- •8.3.2 Grading
- •8.3.3 Risk of PVR
- •8.4 Surgery
- •8.4.1 Mild PVR
- •8.4.2 Moderate PVR
- •8.4.3 Severe PVR
- •8.4.3.1 The Relieving Retinectomy
- •8.4.4 Radial Retinotomy
- •8.4.5 Silicone Oil Injection
- •8.4.6 Applying Laser
- •8.4.7 ROSO Plus
- •8.4.8 Very Severe PVR
- •8.4.9 Choice of Endotamponade
- •8.4.9.1 Silicone Oil or Perfluoropropane Gas
- •8.4.9.2 Heavy Oils
- •8.4.10 Removal of Subretinal Bands
- •8.4.11 Adjunctive Therapies
- •8.4.12 Success Rates
- •8.4.13 Postoperative Complications
- •8.5 Summary
- •References
- •9: Macular Hole
- •9.1 Introduction
- •9.2 Idiopathic Macular Hole
- •9.2.1 Clinical Features
- •9.2.1.1 Introduction
- •9.2.1.2 Watzke–Allen Test
- •9.2.1.3 Grading
- •9.2.1.4 Natural History
- •9.2.1.5 Optical Coherence Tomography
- •9.2.2 Secondary Macular Holes
- •9.2.3 Lamellar and Partial Thickness Holes
- •9.2.4 Surgery
- •9.2.4.1 Introduction
- •9.2.4.2 Surgery
- •9.2.4.3 Peeling the Posterior Hyaloid Membrane
- •9.2.4.4 ILM Peel and Other Adjunctive Therapies
- •9.2.4.5 Choice of Tamponade
- •9.2.4.6 Postoperative Posturing of the Patient
- •9.2.4.9 Visual Field Loss
- •9.2.5 Success Rates
- •9.2.6 Reoperation
- •9.3 Microplasmin
- •9.4 Summary
- •References
- •10.1 Clinical Features
- •10.1.1 Other Conditions
- •10.1.2 Secondary Macular Pucker
- •10.2 Surgery
- •10.3 Success Rates
- •10.5 Membrane Recurrence
- •10.6 Summary
- •References
- •11: Choroidal Neovascular Membrane
- •11.1 Age-Related Macular Degeneration
- •11.1.1 Clinical Features
- •11.1.2 Vitreous Haemorrhage and CNV
- •11.1.3 Pneumatic Displacement of Subretinal Haemorrhage
- •11.1.4 Surgery for Failed Anti-VEGF Therapy
- •11.1.4.1 Introduction
- •11.1.4.2 360° Macular Translocation
- •11.1.6 Success Rates
- •11.2 Choroidal Neovascular Membrane Not from ARMD
- •11.2.1 Introduction
- •11.2.2 Surgery
- •11.3 Summary
- •References
- •12: Diabetic Retinopathy
- •12.1 Introduction
- •12.2 Diabetic Retinopathy
- •12.2.1 Introduction
- •12.2.1.1 Diabetic Retinopathy Grading
- •12.2.2 Diabetic Vitreous Haemorrhage
- •12.2.3 Progression to Vitreous Haemorrhage and Tractional Retinal Detachment
- •12.2.3.1 Clinical Features
- •12.2.3.2 Surgery
- •12.2.4 Diabetic Retinal Detachment
- •12.2.4.1 Clinical Features
- •12.2.4.2 Surgery
- •12.2.4.3 Tractional Retinal Detachment
- •12.2.4.4 Peroperative Panretinal Photocoagulation
- •12.2.4.6 Bimanual Surgery
- •12.2.4.7 Dealing with Bleeding Vessels
- •12.2.4.8 Iatrogenic Breaks
- •12.2.4.9 Silicone Oil
- •12.2.4.10 Combined TRD and RRD
- •12.2.5 Postoperative Complications
- •12.2.5.1 Vitreous Haemorrhage
- •12.2.5.2 Rhegmatogenous Retinal Detachment
- •12.2.5.3 Iris Neovascularisation
- •12.2.5.4 Phthisis Bulbi
- •12.2.5.5 Maculopathy
- •12.2.5.6 Survival After Surgery
- •12.2.6 Success Rates
- •12.2.7 Diabetic Maculopathy
- •References
- •13: Other Vascular Disorders
- •13.1 Introduction
- •13.2 Retinal Vein Occlusion
- •13.2.1 Chorioretinal Anastomosis
- •13.2.2 Arteriovenous Decompression
- •13.2.3 Radial Optic Neurotomy
- •13.2.4 Intravitreal Steroid and Anti-VEGF Agents
- •13.2.5 Tissue Plasminogen Activator
- •13.3 Sickle-Cell Disease
- •13.3.1 Introduction
- •13.3.2 Types of Sickle-Cell Disease
- •13.3.3 Systemic Investigation
- •13.3.4 Inheritance and Race
- •13.3.5 Systemic Manifestations
- •13.3.6 Ophthalmic Presentation
- •13.3.7 Laser Therapy
- •13.3.8 Surgery
- •13.3.9 Visual Outcome
- •13.3.10 Screening
- •13.3.11 Survival
- •13.4 Retinal Vasculitis
- •13.5 Central Retinal Artery Occlusion
- •13.6 Summary
- •References
- •14: Trauma
- •14.1 Introduction
- •14.3 Contusion Injuries
- •14.3.1 Clinical Presentation
- •14.3.2 Types of Retinal Break
- •14.3.2.1 Dialysis
- •14.3.2.2 Pars Ciliaris Tears
- •14.3.2.3 Ragged Tear in Commotio Retinae
- •14.3.2.4 Giant Retinal Tears
- •14.3.3 Surgery
- •14.3.4 Visual Outcome
- •14.4 Rupture
- •14.4.1 Clinical Presentation
- •14.4.2 Surgery
- •14.4.3 Visual Outcome
- •14.5 Penetrating Injury
- •14.5.1 Clinical Presentation
- •14.5.1.1 Endophthalmitis
- •14.5.1.2 Retinal Detachment
- •14.5.2 Surgery
- •14.5.3 Visual Outcome
- •14.6 Trauma Scores
- •14.7 Intraocular Foreign Bodies
- •14.7.1 Clinical Presentation
- •14.7.1.1 Diagnostic Imaging
- •14.7.2 IOFB Materials
- •14.7.3 Surgery
- •14.7.4 The Primary Procedure
- •14.7.5 PPV: The Anterior Segment
- •14.7.5.1 The Lens
- •14.7.6 PPV: The Posterior Segment
- •14.7.7 The Magnet
- •14.7.8 Visual Outcome
- •14.7.9 Siderosis
- •14.8 Perforating Injury
- •14.9 Sympathetic Ophthalmia
- •14.10 Proliferative Vitreoretinopathy
- •14.11 Phthisis Bulbi
- •14.12 When Not to Operate
- •14.12.1 At Presentation
- •14.12.2 Postoperatively
- •14.13 Summary
- •References
- •15.1 Introduction
- •15.2 Dropped Nucleus
- •15.2.1 Clinical Features
- •15.2.2 Surgery
- •15.2.2.1 Primary Management
- •15.2.2.2 Vitrectomy Surgery
- •15.2.2.4 Success Rates
- •15.3 Intraocular Lens Dislocations
- •15.3.1 Clinical Presentation
- •15.3.2 Surgery
- •15.3.2.1 Removal of the IOL
- •15.4 Surgical Options for the Aphakic Eye
- •15.4.1 McCannell Sutured IOL
- •15.4.2 Iris-Clip IOL
- •15.4.3 Haptic Capture Method
- •15.4.4 Anterior Chamber IOL
- •15.4.5 Sutured Posterior Chamber IOLs
- •15.4.6 The Aphakic and Aniridic Eye
- •15.5 Postoperative Endophthalmitis
- •15.5.1 Clinical Features
- •15.5.2 Surgery
- •15.5.2.1 Vitreous Tap
- •15.5.2.2 Vitreous Biopsy
- •15.5.3 Infective Organisms
- •15.5.4 Antibiotics
- •15.5.5 The Role of Vitrectomy
- •15.5.6 Success Rates
- •15.6 Chronic Postoperative Endophthalmitis
- •15.7 Needlestick Injury
- •15.7.1 Clinical Features
- •15.7.2 Surgery
- •15.8 Intraocular Haemorrhage
- •15.9 Retinal Detachment
- •15.10 Chronic Uveitis
- •15.11 Postoperative Cystoid Macular Oedema
- •15.12 Postoperative Vitreomacular Traction
- •15.13 Postoperative Choroidal Effusion
- •15.13.1 External Drainage
- •15.14 Summary
- •References
- •16: Uveitis and Allied Disorders
- •16.1 Introduction
- •16.2 Non-infectious Uveitis of the Posterior Segment
- •16.2.2 Retinal Detachment
- •16.2.3 Cystoid Macular Oedema
- •16.2.4 Hypotony
- •16.2.5 The Vitreous Biopsy
- •16.2.6 Sampling at the Beginning of a PPV
- •16.2.6.1 Special Situations
- •16.3 Acute Retinal Necrosis
- •16.3.1 Clinical Features
- •16.3.2 Surgery
- •16.3.2.1 For Diagnosis
- •16.3.2.2 For Treatment
- •16.3.3 Visual Outcome
- •16.4 Cytomegalovirus Retinitis
- •16.4.1 Clinical Features
- •16.4.2 Surgery
- •16.4.2.1 For Diagnosis
- •16.4.2.2 For Treatment
- •16.4.3 Visual Outcome
- •16.5 Fungal Endophthalmitis
- •16.5.1 Clinical Features
- •16.5.2 Surgery
- •16.5.2.1 For Diagnosis
- •16.5.2.2 For Treatment
- •16.5.3 Visual Outcome
- •16.6 Other Infections
- •16.6.1 Clinical Features
- •16.6.2 Surgery
- •16.6.2.1 For Diagnosis
- •16.6.2.2 Chorioretinal Biopsy
- •16.6.2.3 For Treatment
- •16.6.3 Visual Outcome and Survival
- •16.7 Paraneoplastic Retinopathy
- •16.8 Summary
- •References
- •17: Miscellaneous Conditions
- •17.1 Vitrectomy for Vitreous Opacities
- •17.2 Vitreous Anomalies
- •17.2.1 Persistent Hyperplastic Primary Vitreous
- •17.2.2 Asteroid Hyalosis
- •17.2.3 Amyloidosis
- •17.3 Retinal Haemangioma and Telangiectasia
- •17.4 Optic Disc Anomalies
- •17.4.1 Optic Disc Pits and Optic Disc Coloboma
- •17.4.2 Morning Glory Syndrome
- •17.5 Retinochoroidal Coloboma
- •17.6 Marfan’s Syndrome
- •17.7 Retinopathy of Prematurity
- •17.8 Uveal Effusion Syndrome
- •17.8.1 Clinical Features
- •17.8.2 Surgery
- •17.9 Terson’s Syndrome
- •17.10 Disseminated Intravascular Coagulation
- •17.11 Retinal Prosthesis
- •17.12 Summary
- •References
- •Glossary of Abbreviations
- •Others in Database
- •Appendices
- •Useful Formulae and Rules
- •Cryotherapy
- •Fluids (i.e. Both Gases and Liquids)
- •Gases
- •Liquids
- •Ultrasound
- •Diffusion and Viscosity
- •Visual Acuity
- •Diffusion
- •Fick’s Law
- •Stokes-Einstein
- •Darcy’s Law
- •Starling’s Law
- •Index
194 |
8 Proliferative Vitreoretinopathy |
|
|
Fig. 8.15 A closed ‘funnel’ RRD from PVR on ultrasound, CP12 and CA12
Table 8.1 Grading PVR
Proliferative vitreoretinopathy
Grading
AVitreous haze, pigment clumps, pigment clusters on inferior retina
BInner retinal wrinkling, retinal stiffness, rolled break edges, vitreous stiffness
CP1–12 |
Full-thickness retinal folds or subretinal strands |
|
|
posterior to the equator (described as 1–12 clock |
|
|
hours of involvement) |
|
CA1–12 |
Full-thickness retinal folds or subretinal strands |
|
|
anterior to the equator (described as 1–12 clock |
|
|
hours of involvement), anterior displacement, |
|
|
condensed vitreous strands |
|
Descriptive terms |
|
|
Type |
Usual location |
Features |
Focal |
Posterior |
Star folds in the retina |
Diffuse |
Posterior |
Confluent retinal folding |
Subretinal |
Posterior |
Fibrous strands, linear and purse |
|
|
string around the optic disc |
|
|
Fibrous sheets |
Circumferential |
Anterior |
Contraction of the retina inwards |
|
|
at the posterior edge of the |
|
|
vitreous base |
Anterior |
Anterior |
Anterior traction on the retina at |
displacement |
|
the vitreous base |
|
|
Ciliary body detachment and |
|
|
epiciliary membrane |
|
|
Iris retraction |
Occasionally, the proliferation is predominantly subretinal (Lewis et al. 1989) producing fibrous strands which elevate the retina like the guy ropes of a tent or even ‘purse string’ the retina around the optic disc.
8.3.3Risk of PVR
PVR is particularly likely to occur if the patient has any of the following:
•RRD for a prolonged period (Tseng et al. 2004).
•Choroidal detachment (Cowley et al. 1989).
•Previous surgery or cryotherapy which may aid the dispersion of the RPE cells (Glaser et al. 1993) and their stimulation by growth hormones.
•Pre-existing PVR.
•Aphakia.
•Vitreous haemorrhage on PVR formation is uncertain, but there is an opinion in vitreous surgery that this may increase the risk of PVR (Duquesne et al. 1996).
•Vascular abnormalities such as retinal telangiectasia or angiomas.
•Uveitis.
•Trauma.
Fig. 8.16 A subretinal band of fibrosis can ‘purse string’ the retina around the optic disc
8.3 Clinical Features |
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Fig. 8.17 PVR in the periphery is causing a fold in the retina in the macula
(see Fig. 8.18)
Fig. 8.20 Subretinal fibrosis in a chronic retinal detachment
Fig. 8.18 See previous figure
Fig. 8.21 This patient has a purse string subretinal band which is anchored in the periphery and is dragging retina downwards over the surface of the disc. Another instance of retina pulled over the disc surface is in ‘dragged disc’, for example, retinopathy of prematurity. The surgeon must be aware that retina overlies the disc and care must be taken when draining residual vitreous cavity fluid off the optic nerve head during PPV in these patients because the retina can be aspirated into the flute needle tip
Fig. 8.19 Severe subretinal fibrosis postoperatively
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