Foreword

There is no doubt that serendipity plays an important role in many scientific developments. One very clear example is the evolution of Ophthalmic Coherence Tomography (OCT) in Ophthalmology.

In the early 1970s, Michel Duguay at the AT & T Bell Laboratories published “Light photographed in flight”, where he proposed that echoes of light could be used to examine biological tissue. In the mid-1970s, Erich Ippen, of Massachusetts Institute of Technology (MIT), further developed femtosecond optics. Both discoveries built the foundation of the concept called optical reflectivity, with the idea that light interference could be used to obtain a non-invasive “biopsy” of translucid tissues. In the late 1980s, corneal refractive surgery was at its summit. It required an accurate measurement of corneal thickness. James Fujimoto of MIT collaborated with Ophthalmologists Joel Schuman, David Huang and Carmen Puliafito to refine this measurement, using low-coherence interferometry with only partial success. Nevertheless, in a poorly focused image of the cornea, Huang noticed what appeared to be an optical section of the retina in the background. Instead of dismissing this poorly defined image as useless, Huang continued experimenting until he was able to obtain an optical transverse image of the retina. Thus, retinal and choroidal OCT was born. Today OCT constitutes the most important ancillary test and standard of care in Ophthalmic practice, not only in vitreoretinal pathology, but also in glaucoma and problems of the anterior segment.

More recently, swept-source OCT, which can produce 500,000 scans per second and OCT angiography, employing motion contrast imaging, allow us to image retinal capillaries and the smallest neo-vessels in the retinal tissues. Also, enhanced penetration has allowed to provide detailed visualization of the choroid. New technologies are in constant development, such as visible light OCT (visOCT) and adaptive optics (AO-OCT) will allow further details and deeper penetration.

In this particular section of the book, after a review of general principles and advances of OCT and OCTa use in vitreoretinal disorders, all the contributors and coauthors engage in describing to us the normal and pathological parameters of macular and choroidal perfusion patterns, followed by a description and findings in several vitreoretinal and choroidal pathological disorders.

There is no doubt that all the new and described findings in this book will widen our knowledge and be of benefit to our ailing patients.