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Corneal Physiology and Disposable Contact Lenses.
  1. J A SCOTT

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    Corneal Physiology and Disposable Contact Lenses.By Hikaru Hamano, Herbert E Kaufman. Pp 199; £65. Oxford: Butterworth-Heinemann, 1997. ISBN 0-7506-9927-2.

    In the preface of this book, the aim of promoting the safe use of contact lenses is stated. The text complements this by reasoned use of the scientific literature, and addresses the philosophical nature of the way to advise the modern lens wearer in the balance between ease of use, safety to the cornea, and reliability of the lens in the less than perfect hands of the wearer, and it attempts to define a paradigm for lens wear for the future with current available lens materials.

    Divided into two sections, the shorter Section I concentrates on the essential and relevant anatomy and physiology of the cornea and precorneal tear film. There is also a good introductory chapter on corneal topography. Each chapter is concise, clearly set out, and well illustrated and there is reference to and presentation of experimental evidence for the information provided. It provides an excellent introduction to the second section.

    Section II concentrates on the development of the concept of disposable contact lens. The opening chapter is long, but very readable as it traces the evolution of the contact lens, from original glass to modern materials, and manufacturing methods with some perspective on the commercial decisions behind the lens designs. There is a summary appendix defining the milestones for the reader who may not wish to wade through the whole chapter.

    The other chapters address the modern demands of contact lens design, patient preference, safety, and complications. In an evidence based approach, there is a systematic discussion of the effects of lens wear on the cornea, presenting the clinical and subclinical changes in perspective. The contributors are careful to define concepts of “extended wear” and “disposability”, as well as differences of behaviour in the adapted and non-adapted eye, areas where confusion exists in the public mind as well as some practitioners. Again these chapters are well illustrated with a clear review and presentation of the evidence from basic scientists as well as clinical studies. The chapters on complications are aimed at the pathogenesis rather than a clinical treatment algorithm, which may well become rapidly outdated. There is a sanguine chapter on keratitis and its risk factors related the mode of lens wear which the clinician will be well advised to read.

    The reader will find the text pertinent to UK and European practice: although written by authors working in USA, Japan, and Australia, acknowledgment that the patient base may vary in other continents is made.

    Overall, I found the book to be well presented with a very readable style, well structured, concise, and well supported with scientific evidence and illustrations. There is an extensive bibliography with references drawn from current literature. It does not attempt to be a manual for fitting lenses in normal or medical conditions, nor for treating the complications. It does provide a well argued and rational background for safe use of contact lenses using modern materials from the point of view of the limitations of corneal physiology, while acknowledging patient acceptability. I am sure the reader will find the contents of this book valuable in the management of contact lens wearers, even if they do not regularly fit lenses themselves.