| Chapter 113 The Role of Fluorescein Angiography in Diseases of the Retina and Choroid KENNETH G. NOBLE Table Of Contents |
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| Since the first report 30 years ago of “A method of photographing
fluorescein in circulating blood in the retina” (Novotny HR, Alvis
DL: Circulation 24:82, 1961), the uses and benefits of fluorescein
angiography have been manifold. Although there have been significant
improvements in equipment (cameras, film, matched exciter, and barrier
filters) and technique (stereo photography, fluorescein solution concentrations, film
processing), the actual method of fluorescein angiography
has changed little. What has changed dramatically is the interpretation
of the angiogram in light of 30 years of experience with clinical
and pathologic correlation. It is the single most important, and certainly
most performed, ancillary diagnostic test in retinal and choroidal
diseases. Every textbook that discusses retinal and choroidal disease will include an introductory chapter on fluorescein angiography. The topics usually covered include basic principles, equipment, technique, complications, and the interpretation of the normal fluorescein angiogram. The abnormal angiogram is discussed in schematic fashion with reference to certain diseases by example. In Duane's Clinical Ophthalmology, Volume 3, the reader is referred to Chapter 4 by Drs. Jay L. Federman and Joseph I. McGuire entitled “Intravenous Fluorescein Angiography.” This series of chapters approaches this diagnostic test from the vantage point of the useful and appropriate role of fluorescein angiography in various retinal and choroidal diseases—specifically, how angiography functions in the diagnosis, prognosis, therapy and management, follow-up care, and pathogenesis of these different diseases. The authors for these chapters have a long-standing interest in their topic. Thus, the role of fluorescein angiography will be discussed from their clinical experience and from the perspectives previously outlined. Since these introductory remarks were first written in 1991, there have been a number of new and sophisticated methods for evaluating the retina, choroid, and vitreous. Many of these tests are covered in this section on “Ancillary Diagnostic Techniques.” This includes nerve fiber layer analysis, optical coherence tomography, ultrasonography with improved image quality, color Doppler imaging, and indocyanine green angiography. None of these modalities can improve on what fluorescein evaluates best, the vasculature of the choroid, retina, and optic nerve and changes in pigment (melanin, lipofuscin, hemoglobin) in these structures. Film-based angiography still provides the sharpest and clearest image, especially with stereoscopic viewing of negatives or well-developed positives. However, the introduction of film-free digital imaging has advantages, which for many compensate for the relative decrease in resolution. First, the physician and photographer view the image continually in real time, and modifications can be made from moment to moment. Second, the stored image can be enhanced by computer software to better view possible pathology, and computer overlay provides comparisons with prior studies. Finally, the results are available immediately. Thus, decisions regarding diagnosis, prognosis, and treatment can be discussed with the patient after the test is completed. |