Dr Gilg deals with various topics regarding accommodation and its mechanisms. He discusses the relationship between presbyopia and the different ametropias (hyperopia, myopia), as well as the possible optical compensations with correcting glasses, with the so-called progressive lenses or orthokeratological contact lenses.

Firstly, he defines accommodation, the eye's extraordinary ability to increase its power of convergence. Convergence, simply stated, is the ocular ability to focus light falling from a given distance to a single plane on the retina, by modifying the curvature of the lens. Thus, objects at a finite distance are clearly focused on retina and therefore clearly seen. Crystalline lens covers more on his anterior face during accommodation. During the contraction of ciliary muscle, suspensory ligament relaxes and modifies crystalline lens shape. Accommodation responds to nervous regulation.

Secondly, presbyopia is put back in its scientific context. It appears to occur as a result of several connected ocular phenomena rather than a single causal mechanism. These include an increase in crystalline lens sphericity, anterior translation of the lens, the surrounding action of the iris and cerebral plasticity. Crystalline lens becomes rounder during accommodation; its equatorial diameter decreases and keeps growing in its anterior part (with the reduction of the distance between lens and ciliary muscle). Presbyopia is the loss in amplitude of accommodation. It will physiologically grow weaker as the subject ages, primarily because the lens capsule progressively loses elasticity throughout life. The punctum proximum (the nearest point, the eye can see clearly with maximum accommodation) moves backwards and is located beyond the usual distance of near vision (13 inches). This forces the viewer to move the viewed object farther away in order to place it in clear focus. Presbyopia affects everyone, but first symptoms typically appear around the age 42 to 45 years old for emmetropes (earlier for hyperopes), depending on the habits of each individual.8

Finally, Dr Gilg moves on to cover the highly controversial surgical possibilities for correcting presbyopia. These surgical options use techniques based upon the concepts of monovision and multifocality. They include multifocal presby-LASIK, monovision LASIK, pre-lens implants, multifocal implants, intrastromal corneal ring segments (ICRS), ciliary body sclerotomies, scleral expansion bands and conductive keratoplasty.

In the book, the physician shares his experience, along with his development of a ciliozonular tension ring system, aimed at ensuring the tension of zonular fibers, among other things.

There are many techniques having the goal of restoring accommodation. However, only the test of time, as well as the scientific certification of one or more of these techniques, will allow suggesting them to the patients with maximum safety. Whatever the technique used, it seems that it will be complemented with the classic solution of spectacles, whether fitted with ordinary single focus or progressive multifocal lenses.

This book, aimed at well-informed readers, is above all a didactic and thorough treatment of the subject of presbyopia. Indeed, despite its complex theme, it still raises numerous questions from our patients and our friends. I voluntarily decided to present this arduous topic, in the same way, I would inform either a patient during a consultation, or our young medical students in the operating theater. Furthermore, this work is equally intended for the friends and family of our patients willing to update their knowledge of presbyopia. It is true that today, our refractive patients and these students look alike. In spite of often having insufficient pre-requisite or, even more regrettable, inaccurate or commonplace ideas, they have a great need for accurate information.

Our current role as ophthalmologists, at the risk of becoming technical advisors, is thus also to inform. Indeed, information is at the heart of the doctor-patient relationship, and this is for the best. Those days when ophthalmologists chose the most appropriate treatment, usually without possible or even wanted dialogue, are definitely past.

It is not uncommon in our ophthalmological clinical practice to examine a patient, who arrives apparently perfectly aware of what diagnostic gears to use, and the resulting potential diagnoses. The patient often knows the spontaneous or treated prognosis, has a good knowledge of the various possible treatments, and sometimes even treatments still in experimental stage! This is our daily routine.

It is not uncommon in our ophthalmological clinical practice to examine a patient, who arrives apparently perfectly aware of what diagnostic gears to use, and the resulting potential diagnoses. The patient often knows the spontaneous or treated prognosis, has a good knowledge of the various possible treatments, and sometimes even treatments still in experimental stage! This is our daily routine.

As a matter of fact, in order to relieve, compensate and treat our patients' refractive problems, it is part of our duty to know all the therapeutic means at our disposal.

The level of detail provided by current methods enables us to give clear, fair information and to carry out actions. This is done in accordance with the most recently updated scientific information, as they are defined by the code of medical ethics. It is a matter of determining the best treatment strategy for the patients according to their wishes. They are then able to make the most of their corrected eyesight, and will effortlessly take advantage of a full range of vision, distance, intermediate or near, at different levels of brightness. It is about strategy because, as we will see, the modification of a visual factor can lead to the evolution of other visual variables.10

This technical and technological environment, in aid of the patients, finds itself in ophthalmologic offices or centers and, as a result, the practitioner's investment, in terms of continuing education and financial effort, is significant. Our patients, expecting high-performance, quick and optimized surgery, must be ready to afford high fares and accept low repayments.

The notified reader will gain, page after page, the necessary elements to comprehend the accommodative phenomena stemming from the diverse troubles of vision. He or she should by then, be better armed to understand what functional influences the eruption of presbyopia has over the world's grandma-boomer population.

Given the colossal figures it represents, presbyopia is undeniably a world ailment. Posing a real public health problem, in terms of prevalence and incidence, it also has major economic repercussions and considerable commercial stakes on the planet scale. In France, 27 million are presbyope, 19 million of whom are aged between 45 and 70, as officially listed in the year 2007. Presbyopia has got at 90 million of European individuals, almost as many North Americans, and more than 2 billion human beings on earth! What amazing figures: the reader should find enough motivation to carry on the book, insofar as he or she gets in medical and scientific literature beforehand, to familiarize with the related vocabulary.

We have made up our mind to get the reader to enter the reasoning sphere of modern ophthalmology and its medical jargon, its deductive approach and its critical analysis of present time therapeutics. Regarding the semantic difficulties, just as the scientific or medical gaps, the non-specialist reader might meet with, I have worked out a numbered cross-references from the text. In “Notes” chapter, you will find each uncleared notion mentioned in the book, as long as the digression does not take us too far away from our subject, and the explanation seems indispensable for the debate.

It is difficult to enter a closed world such as ophthalmology without first absorbing its language. It may well be the reason why our colleagues, who practice in different domains, consider us as specialists of our own.

What a shame, it would be for the reader to leave the track before the end of the introductory course! Besides, the search prospects are unexpected and, in near future, the development will bring a visual rejuvenation cure to who wants to get his youthful vision back.

I do hope the book will answer all the readers' questions, or at the very least, that it will provide them with elements likely to rouse their curiosity. As for those who think ocular-lift is no longer a wild dream, visionary researchers are at the right place.