Infections of the Cornea and Conjunctiva

Foreword 1
Foreword 2
Preface
Contents
About the Editors
Contributors
1: Bacterial Conjunctivitis
1.1 Introduction
1.2 Epidemiology
1.3 Risk Factors
1.4 Classification
1.5 Symptoms
1.6 Signs
1.6.1 Papillae
1.6.2 Follicles
1.6.3 Membranes and Pseudomembranes
1.6.4 Granulomas
1.6.5 Cicatricial Changes
1.7 Acute Bacterial Conjunctivitis
1.7.1 Complications
1.8 Hyperacute Bacterial Conjunctivitis
1.9 Complications
1.10 Chronic Bacterial Conjunctivitis
1.10.1 Chlamydial Conjunctivitis
1.10.1.1 Trachoma
1.10.1.2 Inclusion Conjunctivitis
1.10.1.3 Lymphogranuloma Venereum
1.10.2 Deep Fornix Syndrome
1.10.3 Moraxella Conjunctivitis
1.11 Phlyctenular Keratoconjunctivitis
References
2: Viral Conjunctivitis
2.1 Introduction
2.2 The History of Viral Conjunctivitis
2.3 Etiologies of Viral Conjunctivitis
2.4 Adenoviral Conjunctivitis
2.4.1 The Human Adenoviruses
2.4.1.1 Clinical Syndromes Associated with Human Adenovirus
2.5 Herpes Conjunctivitis
2.5.1 The Human Herpesviruses
2.5.2 Herpes Simplex Virus Conjunctivitis
2.5.3 Herpes Simplex Virus Conjunctivitis in Neonates
2.5.4 Varicella Zoster Virus (VZV) Conjunctivitis
2.5.5 Other Herpetic Etiologies of Conjunctivitis
2.6 Picornavirus Conjunctivitis
2.7 Poxvirus Conjunctivitis
2.7.1 Variola (Smallpox) Conjunctivitis
2.7.2 Vaccinia Conjunctivitis
2.7.3 Other Poxvirus-Related Conjunctivitis
2.8 Other Important Causes of Viral Conjunctivitis
2.8.1 Arbovirus Conjunctivitis
2.8.2 Measles, Mumps, and Rubella Conjunctivitis
2.8.3 Conjunctivitis Associated with Human Immunodeficiency Virus
2.8.4 Other Causes of Conjunctivitis
2.9 Diagnostic Evaluation of Viral Conjunctivitis
2.9.1 Traditional Methods of Diagnosis
2.9.2 Molecular Diagnosis of Viral Infections
2.9.3 Whole Genome Sequencing
2.10 Management of Viral Conjunctivitis
2.11 Conclusions and Future Directions
References
3: Chlamydia Conjunctivitis
3.1 Introduction
3.2 Pathophysiology
3.3 Trachoma
3.3.1 Epidemiology
3.3.2 Pathogenesis
3.3.3 Management
3.3.4 Surgery
3.3.5 Antibiotics
3.3.6 Facial Cleanliness and Environmental Improvements
3.4 Inclusion Conjunctivitis
3.4.1 Neonatal Inclusion Conjunctivitis
3.4.2 Adult Inclusion Conjunctivitis
3.5 Lymphogranuloma Venereum
3.6 Chlamydia Psittaci
3.7 Summary
References
4: Ophthalmia Neonatorum
4.1 Introduction
4.2 Incidence
4.3 Etiology
4.4 Clinical Symptoms
4.5 Pathophysiology
4.6 Diagnosis and Investigation
4.7 Prophylaxis
4.8 Management
4.9 Complications
4.10 Prognosis
References
5: Clinical Work-Up of Corneal Ulcers
5.1 Introduction
5.2 Aims of Clinical Evaluation
5.3 History
5.4 Clinical Examination
5.5 Documentation and Diagrammatic Representation
5.6 Interpretation of Clinical Evaluation Findings
5.6.1 Assessment of Severity of Infectious Keratitis
5.6.2 Identification of Probable Etiological Agent (Generating a Differential Diagnosis)
5.6.2.1 Distinctive Features of Specific Bacteria
5.6.2.2 Distinctive Features of Fungi, Acanthamoeba, Microsporidia
5.6.3 Identify Predisposing or the Risk Factors
5.7 How Clinical Features Are Pointers for Specific Microbiology Workup?
5.8 Why Clinical Examination Alone Is Not Reliable?
5.9 Why Microbiological Evaluation of Microbial Keratitis Is Important?
5.10 Role of Confocal Microscopy for Evaluation of Microbial Keratitis
5.11 Conclusions
References
6: Bacterial Keratitis
6.1 Introduction
6.2 Etiology
6.3 Risk Factors
6.4 Role of Ocular and Gut Dysbiosis in Bacterial Keratitis
6.5 Bacterial Keratitis in Children
6.6 Pathology
6.7 Clinical Assessment
6.7.1 Signs and Symptoms
6.7.2 History
6.7.3 Physical Examination
6.7.4 Laboratory Assessment
6.7.5 Laboratory Workup
6.7.5.1 Firmicutes (Gram-Positive Cocci and Rods)
6.7.5.2 Actinobacteria (Gram-Positive Rods)
6.7.5.3 Proteobacteria (Gram-Negative Cocci, Rods)
Bacteroidetes
6.8 Use of Metagenomics to Detect Bacterial Keratitis
6.8.1 Antimicrobial Therapy
6.9 Steroids and Bacterial Keratitis
6.10 Conclusions
6.10.1 Artificial Intelligence and Neural Networks
6.10.2 Next Generation Sequencing
References
7: Atypical Mycobacterial Keratitis
7.1 Introduction
7.2 Clinical Features
7.3 Diagnosis
7.4 Management and Outcomes
7.5 Conclusion
References
8: Nocardia Keratitis
8.1 Introduction
8.2 Epidemiology
8.3 Microbiology
8.4 Risk Factors
8.5 Clinical Presentation
8.6 Differential Diagnosis
8.7 Investigations
8.7.1 Microscopy
8.7.2 Culture
8.7.3 Confocal Microscopy
8.7.4 Molecular Diagnostic-Based Methods
8.8 Management
8.9 Complications
8.10 Outcome
8.11 Conclusion
References
9: Acanthamoeba Keratitis
9.1 Introduction
9.2 Physiology and Life Cycle
9.3 Pathophysiology
9.4 Epidemiology, Risk Factors, and Prevention
9.4.1 Clinical Symptoms
9.5 Diagnostics
9.6 Differential Diagnosis
9.7 Treatment
9.7.1 Conservative Treatment
9.7.1.1 Diamidine and Biguanide
9.7.1.2 Antibiotics
9.7.1.3 Povidone-Iodine and Miltefosine
9.7.1.4 Steroids
9.7.1.5 Antifungals
9.8 Surgical Treatment
9.9 Conclusion
References
10: Microsporidial Keratitis
10.1 Introduction
10.2 Organism
10.3 Risk Factors
10.4 Clinical Features
10.4.1 Keratoconjunctivitis
10.4.2 Stromal Keratitis
10.5 Differential Diagnosis
10.5.1 Keratoconjunctivitis
10.5.2 Stromal Keratitis
10.5.2.1 HSV Stromal Keratitis
10.5.3 Acanthamoeba Keratitis
10.6 Diagnosis
10.6.1 Smears and Stains
10.6.2 Histopathology and Tissue Stains
10.6.3 Transmission Electron Microscopy (TEM)
10.6.4 Confocal Microscopy
10.6.5 Antigen-Based Assays
10.6.6 Cell Culture
10.6.7 PCR-Based Molecular Methods
10.7 Treatment
References
11: Fungal Keratitis
11.1 Introduction
11.2 Epidemiology
11.3 Risk Factors
11.4 Clinical Features
11.5 Classical Clinical Features
11.5.1 Fungal Infection After Cataract Surgery
11.5.2 Fungal Infection After Laser Refractive Surgery
11.5.3 Fungal Infection After Lamellar Surgery
11.6 Diagnosis
11.6.1 Noninvasive Techniques
11.6.1.1 Confocal Microscopy
11.6.2 Invasive Techniques
11.6.2.1 Conventional Microbiological Investigations
11.6.2.2 Sample Collection
11.6.2.3 Direct Microscopic Examination
11.6.2.4 Culture
11.6.2.5 Molecular Methods
11.6.2.6 Histopathology
11.7 Medical Management
11.7.1 Role of Antifungals
11.7.2 Role of In Vitro Susceptibility in the Management of Fungal Keratitis
11.7.3 Role of Novel Drug Delivery Models
11.8 Surgical Management
11.8.1 Superficial Keratectomy
11.8.2 Intrastromal Antifungal Injections
11.8.3 Intracameral Injections
11.8.4 Tissue Adhesives
11.8.5 Therapeutic Penetrating Keratoplasty
11.8.6 Lamellar Keratoplasty
11.8.7 Conjunctival Flaps
11.8.8 Collagen Cross-Linking
11.9 Conclusions
References
12: Pythium Keratitis
12.1 Introduction
12.2 The Organism
12.3 Clinical Features
12.4 Diagnosis
12.5 Treatment
12.6 Prognosis
References
13: Herpes Simplex Virus (HSV) Keratitis
13.1 Background
13.2 Manifestations of HSV Keratitis
13.2.1 Epithelial Keratitis
13.2.2 Stromal Keratitis
13.2.3 Endothelial Keratitis
13.2.4 Keratouveitis
13.3 Diagnosis
13.4 Special Circumstances
13.4.1 Pediatric Disease
13.4.2 Bilateral Disease
13.4.3 Recurrent Disease
13.4.4 Prophylaxis
13.5 Management of Sequelae
13.5.1 Neurotrophic Keratopathy
13.5.2 Corneal Opacification
13.6 Future Directions
References
14: Herpes Zoster Ophthalmicus (HZO) Keratitis
14.1 Epidemiology
14.2 Herpes Zoster Virus
14.2.1 Ocular Involvement with Varicella
14.2.2 Herpes Zoster Ophthalmicus
14.2.3 HZO Dermatitis
14.2.4 HZO Conjunctivitis
14.2.5 HZO Keratitis
14.2.6 Epithelial Keratitis
14.2.7 Stromal Keratitis (Interstitial Keratitis)
14.2.8 Endotheliitis
14.2.9 Keratouveitis
14.2.10 Trabeculitis
14.2.11 Neurotrophic Keratitis
14.2.12 Lipid Keratopathy
14.2.13 Postherpetic Neuralgia
14.3 Diagnosis
14.4 Treatment of HZO
14.4.1 Epithelial Keratitis
14.4.2 Stromal Keratitis and Keratouveitis
14.4.3 Neurotrophic Ulcers
14.4.4 Postherpetic Neuralgia
14.5 Surgery
14.6 Herpes Zoster Vaccinations
14.7 Summary
References
15: Role of Microbiology in the Diagnosis of Corneal and Conjunctival Infections
15.1 Introduction
15.2 Role of Microbiology in the Diagnosis of Conjunctival and Corneal Infections
15.3 Clinical Sample Collection
15.4 Sample Processing and Direct Smear Examination
15.5 Culture of Bacteria, Fungi, and Parasites (Acanthamoeba)
15.6 Identification of Bacteria and Fungi
15.7 Culture of Viruses
15.8 Antibiotic Susceptibility Testing
15.9 Molecular Methods
15.9.1 Polymerase Chain Reaction
15.10 Conclusion
References
16: Role of Histopathology in the Diagnosis of Corneal and Conjunctival Infections
16.1 Introduction
16.2 Handling of Corneal Specimens
16.3 General Histologic Changes in Corneal Infections
16.4 Histopathology of Corneal Infections
16.4.1 Bacterial Keratitis
16.4.2 Fungal Keratitis
16.4.3 Viral Keratitis
16.4.3.1 Necrotizing Stromal Keratitis (NSK)
Histopathology of NSK
16.4.3.2 Immune Stromal Keratitis (ISK)
Histopathology of ISK
16.4.4 Acanthamoeba Keratitis
16.4.5 Nocardia Keratitis
16.4.6 Atypical Mycobacterial Keratitis
16.4.7 Microsporidial Keratitis
16.4.8 Pythium Keratitis
16.4.9 Miscellaneous Infections and Infection-Like Conditions
16.4.9.1 Treponema pallidum
16.4.9.2 Mycobacterium tuberculosis
16.4.9.3 Mycobacterium leprae
16.4.9.4 Onchocerciasis
16.4.9.5 Shield Ulcer
16.4.9.6 Tunnel Infection
16.4.9.7 Infectious Crystalline Keratopathy
16.4.9.8 Mixed Infections
16.5 Molecular Diagnosis
16.6 Tips for Diagnosis of Corneal Infections
16.7 Conjunctival Infections
16.8 Conclusion
References
17: Role of In Vivo Confocal Microscopy in the Diagnosis of Microbial Keratitis
17.1 Introduction
17.2 In Vivo Confocal Microscopy
17.3 Image Acquisition Modes
17.3.1 Slit Scanning IVCM
17.3.2 Laser Scanning IVCM
17.3.2.1 Section Mode
17.3.2.2 Volume Mode
17.3.2.3 Sequence Mode
17.4 Clinical Examination Technique
17.4.1 Slit Scanning IVCM
17.4.2 Laser Scanning IVCM
17.5 The Healthy Cornea
17.6 Nonspecific Signs of Infection
17.6.1 Leukocytes
17.6.2 Langerhans Cells
17.7 Acanthamoeba Keratitis
17.8 Fungal Keratitis
17.9 Microsporidia Keratitis
17.10 Nocardia Keratitis
17.11 CMV Endotheliitis
17.12 Conclusions
References