Prologue

The always rich and complex reality escapes any attempt to materialize it in simple words. Perhaps that is why man has resorted, with greater or lesser fortune, to symbols as a means to reflect it. To summarize a phenomenon as unfathomable as music he has used, for example, instruments as an emblem. It has been said, thus, that the eighteenth century was that of the violin, the nineteenth that of the piano or the twentieth that of the guitar. In medicine it could be said that the XVIII was the century of anatomy, the XIX that of physiology and the XX that of surgery. Although there will be many who discuss the latter – in favor of pharmacology, immunology or even radiology –, one of the greatest achievements of surgery in that period has undoubtedly been transplants and keratoplasty in ophthalmology.

Although the idea of replacing the cornea, whether through a transplant or a prosthesis, had been formulated much earlier, its successful application precisely happens for the first time just at the beginning of the 20th century. And throughout it, keratoplasty passes from being an almost heroic procedure, to not only a routine practice but also to occupying the first place among transplants in humans.

Beyond its dominant position in corneal surgery, the evolution of keratoplasty itself, led to one of the new subspecialties of greater weight and dynamism, that of refractive surgery. The great development of this in the last decades, technology apart, cannot be understood without considering its roots in keratoplasty.

The key to this "success story" must be sought in the special situation of the cornea: an external element, easily accessible, but of crucial importance for vision. This makes her vulnerable to a great variety of aggressions or pathologies, while a peculiar physiology limits her capacity to recover the transparency after them. It is therefore natural that replacing it with a transplant or prosthesis is the preferred option in the face of irreversible damage. And at the same time, traits such as its lack of vessels, give it a place of privilege in the face of transplants.

Predicting the future is always a risky exercise, in medicine no less than in other disciplines. The 21st century through which we are advancing, is promising in many fields that will undoubtedly change, perhaps radically, our specialty. We can see it in the progress of genetics, regenerative medicine, robotics or nanotechnology. But today and here, in the decade and a half that we have lived, and without leaving the surgical field, the most evident development is also a consequence of the particular constitution of the cornea. More than a tissue in the histological sense of the term, it is a small organ within the visual organ, composed of a series of layers of well-differentiated structure and function. It was only a matter of time before the hegemony of penetrating keratoplasty gave way to a sheet-by-sheet approach, in logical response to the different ways in which pathologies affect the cornea, being often limited to one or some of them. The authors of this work present this fact, which is marking and undoubtedly will continue to mark the keratoplasty in the XXI century. For this purpose, they dedicate a good part of this work to describe and discuss the different techniques of lamellar keratoplasty, without forgetting its origin in the penetrating one, with its most restricted current scope, up to the alternatives of transplants, keratoprostheses and the novel treatments that are glimpsed in a future that starts today.

This book stands out for a series of balances: between innovation and long-cultivated wisdom, between globalized information and the personal experience of experts, between statistics and the demonstration case, between theory and practical advice, between the didactic and controversies. And, as in most of the written works from now on, the text – obligatorily concise – and the illustrations – necessarily fixed and limited in printed material – are only the gateway to a world of additional and dynamic content, only limited y what the current information technology allows. Therefore, this work will be not only a reference for those interested in the field of keratoplasty, but also a true experience for all readers who venture into its pages.