Revolutions within the contact lens industry are relatively rare. However, the development of silicone hydrogel lenses for extended or continuous wear represents a potentially dramatic improvement in the lenses which we are able to prescribe to our patients. To illustrate the impact of these new lenses, some have claimed that the introduction of these new lenses represents the most significant advance in contact lens technology since the first polyHEMA lenses were introduced in the early 1970s.

The introduction of a new book which is specifically targeted at this new class of contact lenses is therefore extremely welcome. This book is a results of a major education day held in conjunction with the annual conference of the British Contact Lens Association. Each of the eight speakers has contributed a chapter (with co-authors) in this book which covers a wide range of information about these lenses: material science, their clinical application, corneal physiology and the practical implementation of this modality into contact lens practice.

The first chapter is written by Brian Tighe and is a quite excellent review of the development of the new materials. The area is technically complex, yet the information is conveyed in an easily digestible manner, covering the proposed clinical benefits of silicone hydrogel materials, patent history and surface properties. I found the descriptions of the surface treatments for the two currently-available lenses especially helpful, with references to terms such as a ‘0.05 x 0.05mm miniature chessboard’ and ‘glassy silicate islands’ making this section enjoyable to read.

In Chapter 2, Graeme Wilson provides a review of the ocular surface epithelium and its relevance to contact lens wear. Chapter 3, by Mark Willcox and colleagues, reflects on ocular surface processes which are responsible for its anti-microbial action and inflammatory response, and how these processes can change with sleep and with overnight contact lens wear. I particularly enjoyed the review of the defensive role of the tear film via the lacrimal gland proteins such as lysozyme and lactoferrin.

Chapter 4 by Michel Guillon and Cécile Maissa addresses one of the remaining clinical concerns with silicone hydrogel lenses: tear exchange. An important ocular defence mechanism is blinking and tearing, and much of the effectiveness of this system is lost when contact lenses are worn on a continual basis. The authors note that rigidity with silicone hydrogels is much greater than with conventional lens materials and that this causes a relatively high ‘squeeze pressure’ in the mid-periphery and which can also mean that the fit of the lens is more closely related to the lens parameters than conventional soft lenses. A review of both fluid exchange and particle exchange data causes the authors to recommend the clinical examination of post lens debris soon after eye opening when silicone hydrogels are worn.

In Chapter 5, Deborah Sweeney and colleagues present data on the clinical performance of the new lenses and conclude that hypoxic effects (such as microcysts and redness) are eliminated.

In my view, Chapter 6 is the centrepiece of this work. Here, Brien Holden and his co-authors discuss the adverse events and infections which might be seen with silicone hydrogel lenses. This chapter is required reading for clinicians fitting and managing patients with these lenses; indeed, with the numbers of these lenses on the increase, I would suggest that all contact lens clinicians are likely to see patients in this modality and an understanding of the correct clinical management of any ocular reactions is imperative. The chapter reviews the range of conditions which can be seen, from the serious to the incidental, their incidence and presentation, signs and symptoms and clinical management.

Desmond Fonn and colleagues discuss the factors which affect the success of these new lenses in Chapter 7, reflecting on the reasons patients have discontinued with previous lens types; they present data which suggests that comfort may be superior with silicone hydrogels than with conventional lenses. In the final chapter, Noel Brennan and Chantal Coles reflect on the use of silicone hydrogels in everyday practice. They present their views on practice systems which can be employed with these lenses such as out of hours contact numbers, aftercare schedules, consent forms and information forms. This chapter should act as a helpful reference for practitioners keen to update their contact lens systems and procedures.

Overall this book presents up-to-date information on these exciting and important contact lenses. In a sense, the chapters could all stand on their own, and there is considerable overlap in parts, due to the manner in which this book arose from an educational event. However, it seems to me that this book is essential for all contact lens practitioners from both the ‘carrot’ and the ‘stick’ viewpoints. From the ‘carrot’ side, there is so much information available here in one book, that practitioners can learn so much about these products so quickly. The information is well presented and nicely illustrated. The ‘stick’ is that practitioners can no longer ignore the development of these lenses and the increased clinical management which is likely to be required. Even those not choosing to offer this modality to their patients will inevitably have patients wearing the lenses coming to their practices. It is imperative that as a professional group we are able to understand and manage the clinical conditions which may present, for the benefit of both the lens wearers and our professions.