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Due to the fact that this book will reach ophthalmologists from different countries with different training, cultures and backgrounds, the procedures and practices described in this book should be implemented in a manner consistent with the professional standards set for the circumstances that apply in each specific situation. Every effort has been made to confirm the accuracy of the information presented and to correctly relate generally accepted practices. The authors, editors, and publisher cannot accept responsibility for errors or exclusions or for the outcome of the application of the material presented herein. There is no expressed or implied warranty for this book or information imparted by it.

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This volume of “Optical Coherence Tomography in Macular Diseases and Glaucoma-ADVANCED KNOWLEDGE” intends to be the continuation of the previous “BASIC KNOWLEDGE” volume. The authors have tried to illustrate some of the most fascinating applications of modern OCT to varied clinical scenarios as well as its impact on clinical trials and practice as an objective procedure to evaluate the presence of disease and its progression.

The twelfth-century French philosopher Bernard of Chartres used to say that we are like dwarves perched on the shoulders of giants. Medicine like other sciences is a relay race where our contribution is to develop and take further the ideas and investigations of previous investigators and clinicians. To them we dedicate our special recognition and gratitude, as well as to the dedicated staff at JAYPEE HIGHLIGHTS, who have tirelessly worked and made possible the production of this Volume.

Patients with macular disease present great challenges to ophthalmologists. The traditional clinical means of retina examination with slit-lamp biomicroscopy, fundus photography, and fluorescein or ICG angiography—although imperative—are mostly invasive or inadequate for producing optical cross sectional images of the retina and choroid. Angiography is time consuming at follow-up and has limited value unless there is vascular leakage. Slit-lamp examination cannot differentiate intraretinal edema (even with high magnification) or provide precise information about the thickness of the nerve fiber or other retinal layers. Although visual acuity is useful for recording the function of the central retina, it is subjective and lacks an anatomical correlation when visual fluctuations are minute.

To accompany advances in therapeutic capability of managing retinal diseases (with anti-VEGFs and numerous intravitreally injected medications), we need refined non-invasive instrumentation to provide objective information for proper management and follow-up of retinal and choroidal diseases and glaucoma. In the late1980s, optical coherence tomography (OCT) was developed, enabled by scientific progress in optical imaging, computer processing, and clinical awareness of its use in many fields of medicine and ophthalmology. Ophthalmology is in debt to many pioneers in this field— Fijimoto, Huang , Puliafito, Drexler, deBoer, and Schuman, to name a few. Since then, publications have increased on the improvement of the instrumentation and its clinical application for retinal diseases, glaucoma, and the anterior segment. These investigations led from the development of time-domain OCT to sprectral-domain OCT (SD-OCT) and ultrahigh resolution OCT (UHR-OCT), with axial image resolution of 2-3 microns. With SD-OCT, our ability to image microstructures has reached an unprecedented histologic level, permitting visualization of retinal photoreceptor inner and outer segments. Abnormalities in inner and outer photoreceptor segments seen with OCT can now be correlated with changes in visual acuity. OCT is complementary to other established means of examination and provides an optical biopsy of the tissue by performing volumetric and thickness measurement of the nerve fiber layer and other retinal structures. Rapid data acquisition led to 3-D OCT for better delineation of the vitroretinal juncture, internal layers of the retina, and the retinal vascular network and retinochoroidal interface. Further improvements in instrumentation include the use of adaptive optics and automated eye tracking to correct optical aberrations and eliminate the effect of saccadic eye movement for obtaining better retinal images. OCT can be also used to evaluate physiological functions of the retina with perimetry, hyperspectoral imaging of tissue oxygenation, and retinal blood flow velocity as in doppler OCT.5

The field of ophthalmic OCT has evolved beyond our initial expectations and will likely surprise us more in the future. Recent investigations include the use of 1050 nm wavelength, which permits better beam penetration through the retinal pigment epithelium (RPE) and provides enhanced images of the choroid. The segmentation technique permits analysis of individual layers of the retina. Applications of OCT have expanded beyond initial clinical use in wet age-related macular degeneration (ARMD) and diabetic macular edema. OCT now provides information on the health of the choriocapillaris and quantification of RPE damage in dry ARMD, measurement of the retinal nerve fiver layer, optic nerve head assessment in glaucoma, and imaging of anterior segment structures.

The authors of this well illustrated, comprehensive book describe the fundamentals of OCT and demonstrate OCT features in many diseases of the retina and in eyes with the glaucoma. This scholarly written and comprehensive book effectively compiles the work of many experts in the field. It illustrates clinical features with color fundus photographs, corresponding fluorescein angiography, and correlation with the OCT images. This book enlightens readers on applications of OCT as a powerful tool in clinical diagnosis and treatment of patients with retinal disease. Practitioners will find it an invaluable guide to the management of patients with retinal disease and glaucoma.