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KERATITIS Edited by Muthiah Srinivasan Keratitis Edited by Muthiah Srinivasan Published by InTech Janeza Trdine 9, 51000 Rijeka, Croatia Copyright © 2012 InTech All chapters are Open Access distributed under the Creative Commons Attribution 3.0 license, which allows users to download, copy and build upon published articles even for commercial purposes, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications. After this work has been published by InTech, authors have the right to republish it, in whole or part, in any publication of which they are the author, and to make other personal use of the work. Any republication, referencing or personal use of the work must explicitly identify the original source. As for readers, this license allows users to download, copy and build upon published chapters even for commercial purposes, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications. Notice Statements and opinions expressed in the chapters are these of the individual contributors and not necessarily those of the editors or publisher. No responsibility is accepted for the accuracy of information contained in the published chapters. The publisher assumes no responsibility for any damage or injury to persons or property arising out of the use of any materials, instructions, methods or ideas contained in the book. Publishing Process Manager Jana Sertic Technical Editor Teodora Smiljanic Cover Designer InTech Design Team First published April, 2012 Printed in Croatia A free online edition of this book is available at www.intechopen.com Additional hard copies can be obtained from orders@intechopen.com Keratitis, Edited by Muthiah Srinivasan p. cm. ISBN 978-953-51-0568-8 Contents Preface VII Chapter 1 An Overview of Fungal Keratitis and Case Report on Trichophyton Keratitis 1 Ivana Mravičić, Iva Dekaris, Nikica Gabrić, Ivana Romac, Vlade Glavota and Emilija Mlinarić- Missoni Chapter 2 Bacterial Keratitis – Causes, Symptoms and Treatment Hadassah Janumala, Praveen Kumar Sehgal and Asit Baran Mandal Chapter 3 Keratitis Caused by Onchocerciasis: Wolbachia Bacteria Play a Key Role 31 G. Kluxen and A. Hoerauf Chapter 4 Corneal Collagen Cross-Linking Using Riboflavin and Ultraviolet-A Irradiation in Keratitis Treatment 45 Vassilios Kozobolis, Maria Gkika and Georgios Labiris 15 Preface Readers may have access to several textbooks and peer reviewed journals about Keratitis, both in print and on-line versions. Recently due to advanced information technology made available even in developing nations; online publications have been viewed by several health professionals and public as a reliable source of information about health. This kind of publications works cheaper and could be shared by many users. Traditionally the title Keratitis covers non-infective and infective forms but the later one had been described elaborately in most of the languages. The contributing authors of this book have shifted their focus towards recent advances about Keratitis with their vast experience and expertise. Over the past few decades we have witnessed major expansion in the field of Keratitis and these chapters in this book will certainly improve the skill and knowledge of the readers involving patient management, clinical and basic research. Keeping up with the broad advance in technology and treatment strategy is challenging but is essential if we are to utilize this knowledge effectively for patient care. As you open this book I hope you as a reader will appreciate the efforts of dedicated authors, reviewer and publisher to further enhancing the health science for better outcome. Dr. Muthiah Srinivasan Chief Medical Officer, Aravind Eye Hospital and Postgraduate Institute of Ophthalmology, India 1 An Overview of Fungal Keratitis and Case Report on Trichophyton Keratitis Ivana Romac1, 1University Ivana Mravičić1, Iva Dekaris1, Nikica Gabrić1, Vlade Glavota1 and Emilija Mlinarić- Missoni2 Depertment of Ophthalmology, Eye hospital „Svjetlost“, Zagreb, 2Croatian National Institute of Public Health, Zagreb, Croatia 1. Introduction 1.1 Keratitis Keratitis represents corneal inflammation from various causes and clinical manifestations. (Table 1.) It might affect populations of all ages, both males and females with variable incidence. The cornea has a few different defensive mechanisms because it is constantly exposed to external pathogens and enviromental influences: • • • • reflexive eye closing flushing effect of tearing epithelium diffusion barrier very quick regeneration ability Due to impaired defensive mechanisms caused by injuries or little epithelial defects , different types of pathogens or environmental influences might induce corneal inflammation (keratitis). The form of corneal inflammation called superficial keratitis involves just the corneal surface (epithelium). If the inflammation involves corneal stroma it is called stromal or interstitial keratitis. Keratitis might be mild, moderate or severe and may involve other parts of the eye. It might be acute or chronic, infectious or noninfectious. All conditions that lead to epithelial break are possible risk factors to induce keratitis. Microorganisms cannot invade an intact, healthy cornea and infection rarely occurs in the normal eye because the human cornea is naturally resistant to infection. Keratitis Noninfectious Superficial punctate keratitis Exposure keratitis Neuroparalytic keratitis Table 1. Types of keratitis Infectious Bacterial keratitis Viral keratitis Fungal keratitis Protozoal keratitis 2 Keratitis 1.1.1 Noninfectious keratitis Noninfectious keratitis represents corneal inflammation with no known infectious cause. There is a wide spectrum of eye disorders that might be the very reason for this frequent corneal manifestation causing defects of corneal epithelium. This includes: • • • • • • tear film disturbances eyelid anomalies and inflammations physical or chemical trauma allergies problems with contact lens wearing facial neuropathy Persisting epithelial defects are typically accompanied by this form of keratitis. Pain, tearing, redness, photophobia and decreased visual acuity are the most common clinical symptoms. Alongside symptomatic therapy, treatment also depends on the specific cause and it is aimed at promoting corneal healing. 1.1.2 Infectious keratitis Infectious keratitis (microbial keratitis) as the most frequent cause of keratitis is a sight threatening process characterized by defects of corneal epithelium with inflammation of underlying corneal stroma. Bacteria, viruses, fungi and parasitic organisms are all possible causes of this medical emergency condition. The most common predisposing risk factors to develop infectious keratitis include overnight or extended contact lens wear, inadequate disinfection of contact lenses (contamination of the contact lens storage case or contact lens solution), trauma, previous ocular and eyelid surgery, especially corneal surgery (refractive surgery and keratoplasty), chronic ocular surface disease (tear film defficiencies , corneal exposure due to abnormalities of eyelid anatomy and function, systemic diseases (diabetes mellitus, immunocompromised status), extended use of topical corticosteroids. In about 10%of patients with infectious keratitis none of these risk factors was recognized. Clinical presentation varies and depends on the type of causative agent. Patients usually present with redness, tearing, rapid onset of pain and blurred vision. Varied physical findings can be revealed using slit lamp biomicroscopy and external examination will reveal : eyelid edema, conjunctival hyperemia , corneal ulceration, corneal infiltrates, stromal inflammation of the cornea, anterior chamber reaction with or without hypopion, Descemet folds, endothelial inflammatory plaques, posterior synechiae. Infectious keratitis as a serious and possible eye threatening medical emergency requires prompt and adequate treatment. Treatment options include local and systemic antibacterial, antifungal and antiviral medications that depend on the underlying cause and severity of disease. 1.2 Fungal keratitis Fungal keratitis or keratomycosis refers to an infective process of the cornea caused by any fungal species capable of invading the ocular surface. It is a result of fungal colonization or epithelial infiltration and/or invasion of the corneal stroma. It is most typically a slow, relentless disease that must be differentiated from other types of corneal conditions with similar presentation; especially its bacterial counterpart.