Ординатура / Офтальмология / Английские материалы / Diabetes and Ocular Disease Past, Present, and Future Therapies 2nd edition_Scott, Flynn, Smiddy_2009
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104 Diabetes and Ocular Disease
Figure 6.3. Meyer-Schwickerath’s early photocoagulator using a carbon arc light source.
LASER PHOTOCOAGULATION
During this time, there was increasing interest and research to adapt wavelengths produced by newly invented lasers for photocoagulation. Campbell [19,20] and Zweng (Fig. 6.9) [21] independently used ruby laser wavelengths with limited success in the early 1960s. Beetham [22] and Aiello (Fig. 6.8) [23] had better results treating diabetic retinopathy with ruby laser photocoagulation a few years later, especially with widespread scatter panretinal photocoagulation (PRP).
Figure 6.4. Meyer-Schwickerath with photocoagulator using a xenon light source.
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Figure 6.5. Paul Wetzig, M.D.
In the late 1960s, the potential value of laser wavelengths produced with argon gas was recognized. Independent research by L’Esperance (Fig. 6.10) and coworkers [24,25], and Little (Fig. 6.11) and Zweng [26,27] and their associates resulted in the adaptation of argon laser wavelengths with delivery systems for successful retinal photocoagulation.
The successful treatment of diabetic retinopathy with argon laser wavelengths was also reported by Patz (Fig. 6.12) [28]. When the argon laser was developed, it was hoped that the absorption of green wavelengths by hemoglobin would allow direct treatment of elevated neovascularization. Efforts to close neovascularization
Figure 6.6. Professor Pierre Amalric.
Figure 6.7. Edward Okun, M.D., Professor of Ophthalmology at Washington University School of Medicine and Director of Washington University Ophthalmology Department Retina Service using binocular xenon photocoagulation.
Figure 6.8. William Beetham, M.D., and Lloyd M. Aiello, M.D., Directors of Beetham Eye Unit of Joslin Diabetes Center, Boston, Massachusetts evaluating panretinal photocoagulation with a ruby laser.
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Figure 6.9. Christopher Zweng, M.D., adapting laser wavelengths for retinal photocoagulation.
Figure 6.10. Francis L’Esperance, M.D., adapting laser wavelengths for retinal photocoagulation.
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Figure 6.11. Hunter Little, M.D., adapting laser wavelengths for retinal photocoagulation.
Figure 6.12. Arnall Patz, Professor and Chair of Johns Hopkins Department of Ophthalmology and Director of Wilmer Ophthalmological Institute evaluating histopathology of diabetic retinopathy.
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by treating feeder arteriolar vessels of elevated neovascular fronds were usually unsuccessful, despite retreatments several times within a few days. This technique was abandoned because of its lack of efficacy and because it often produced vitreous hemorrhages. Unless the stimulus for neovascularization was reduced, the treated new vessels simply reopened and continued to proliferate.
The studies of Davis (Fig. 6.13) on the natural history of diabetic retinopathy [29,30] had documented that the neovascular component in some cases resolved spontaneously into a fibrotic scar before loss of vision occurred. Another important observation [13,16] was the apparent protection against developing diabetic retinopathy in eyes with extensive chorioretinal scarring and optic atrophy. This led to further attempts to induce regression of neovascularization to preserve vision by applying a standardized pattern of PRP that would spare the macula but reduce the stimulus for neovascular proliferation.
Fundus photography and fluorescein angiography provided valuable additional information on the vascular changes of diabetic retinopathy progressing from capillary damage, edema, nonperfusion and ischemia, and neovascular proliferation [31–37]. Specific identification of leakage sites for focal laser photocoagulation when treating macular edema [38–42], and areas of nonperfusion for PRP when treating neovascular proliferation became possible.
Figure 6.13. Matthew Davis, M.D., Professor and Chair of University of Wisconsin Ophthalmology Department, Director of Diabetic Retinopathy Study, Director of Diabetic Retinopathy Vitrectomy Study.
110 Diabetes and Ocular Disease
Regression of diabetic retinopathy and preservation of vision had also been observed following loss of pituitary function, and therapeutic roles of pituitary ablation were also being studied.
Various surgical and irradiation procedures were developed for pituitary ablation [43–46], but this form of therapy was abandoned with the development of photocoagulation, which was much simpler to perform, had fewer systemic side effects, and produced better results.
There was increasing awareness of the number of people developing diabetes and having loss of vision from diabetic retinopathy complications. In 1968, Drs. Stuart Fine and Morton Goldberg of the United States Public Health Service organized an international meeting on diabetic retinopathy and its treatment at the Airlie House Convention Center near Washington, DC (Fig. 6.14).
Although numerous scientific presentations were given on the natural history of diabetic retinopathy and its treatment with photocoagulation and pituitary gland suppression, the need for more and better data on the natural history and the indications, techniques, and results of photocoagulation collected in a standardized manner at multiple clinical centers was recognized.
The National Eye Institute (NEI), under the direction of Dr. Carl Kupfer, supplied the necessary funding for a series of very successful large collaborative clinical trials on the natural history and treatment of various stages of diabetic retinopathy. In addition, Dr. Frederick Ferris (Fig. 6.15), Director, Division of Epidemiology and Clinical Research, and Clinical Director of the NEI, provided equally important encouragement, advice, and leadership for these projects.
Figure 6.14. Participants of U.S. Public Health Service International Meeting on diabetic retinopathy organized by Dr. Stuart Fine and Dr. Morton Goldberg at the Airlie House Convention Center in 1968.
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Figure 6.15. Frederick Ferris, M.D., Director of the National Eye Institute’s Division of Epidemiology and Clinical Research, and Clinical Director of the National Eye Institute.
The first of these clinical trials, the Diabetic Retinopathy Study (DRS) [47], was directed by Dr. Matthew Davis. It documented the increased risk of blindness with progression of diabetic retinopathy, and the success of PRP produced with either xenon light or argon laser wavelengths in regressing diabetic retinopathy and preserving vision. The very successful DRS was followed by the Early Treatment Diabetic Retinopathy Study (ETDRS) [48] with Dr. Lloyd M. Aiello as Director. It documented the value of argon laser photocoagulation in treating macular edema and reducing loss of vision. Each of these important clinical trials, their major findings and impact on establishing the standards of care for diabetic retinopathy, are presented in much more detail elsewhere in this book.
Additional studies further evaluated laser treatment procedures and techniques for treating diabetic retinopathy [49–54].
VITREOUS SURGERY
Coincidental with the development of photocoagulation treatment of diabetic retinopathy, radical new concepts and revolutionary surgery for the management of diseases and disorders affecting the vitreous were being developed at the Bascom Palmer Eye Institute of the University of Miami School of Medicine in Florida. Dr. David Kasner (Fig. 6.16) had successfully restored vision in an eye with amyloidosis by removing a large portion of the opaque formed vitreous. He had achieved good results with similar aggressive techniques while teaching ophthalmology residents how to manage loss of vitreous during cataract surgery at the Miami Veterans Administration Hospital.
Dr. Robert Machemer (Fig. 6.17), also at the Bascom Palmer Eye Institute and the Miami Veterans Administration Hospital, was intrigued with Dr. Kasner’s
Figure 6.16. David Kasner, M.D., Clinical Faculty of Bascom Palmer Eye Institute of the University of Miami School of Medicine and Veterans Administrative Hospital of Miami, Florida.
Figure 6.17. |
Robert |
Machemer, M.D., Professor of Ophthalmology at Bascom Palmer |
Eye Institute |
of the |
University of Miami, and Professor and Chair of Duke University’s |
Ophthalmology Department and Director of Duke University’s Eye Center. Dr. Machemer is universally recognized as the father of vitreous surgery.
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Figure 6.18. Edward W. D. Norton, M.D., Professor and Chair of University of Miami’s Department of Ophthalmology and Director of the Bascom Palmer Eye Institute.
success, and began a research program to develop surgery to correct vitreous diseases and restore vision. With the support and encouragement of Dr. Edward W.D. Norton (Fig. 6.18), Chairman of the Bascom Palmer Eye Institute, Dr. Machemer worked with Dr. Helmut Buettner and Mr. Jean Marie Parel and their coworkers to develop microsurgical instruments (Fig. 6.19) and procedures with which the contents of the vitreous cavity could be safely removed through the pars plana while maintaining intraocular pressure and a formed globe [55,56].
Figure 6.19. First prototype of pars plana vitrectomy instrument combining vitreous infusion, suction, and cutting by a rotating auger enclosed in the tip in a single instrument.