Indocyanine Green: Historical Context, Current Applications, and Future Considerations.

BACKGROUND: Indocyanine green (ICG) is a dye used in medicine since the mid-1950s for a variety of applications in in cardiology, ophthalmology, and neurosurgery; however, its fluorescent properties have only recently been used in the intraoperative evaluation of tissue perfusion. METHOD: A literature review was conducted on the characterization and employment of ICG within the medical field. Historical and current context of ICG was examined while also considering implications for its future use. RESULTS: ICG is a relatively nontoxic, unstable compound bound by albumin in the intravascular space until rapid clearance by the liver. It has widespread uses in hepatic, cardiac, and ophthalmologic studies, and its use in analyzing tissue perfusion and identifying sentinel lymph nodes in cancer staging is gaining popularity. CONCLUSIONS: ICG has myriad applications and poses low risk to the patient. Its historical uses have contributed to medical knowledge, and it is now undergoing investigation for quantifying tissue perfusion, providing targeted therapies, and intraoperative identification of neurovascular anatomy, ophthalmic structures, and sentinel lymph nodes. New applications of ICG may lead to reduction in postoperative wound-related complications, more effective ophthalmologic procedures, and better detection and treatment of cancer cells.

Digital indocyanine green videoangiography and choroidal neovascularization. 1992.

This report describes a new system for digital indocyanine green videoangiography (ICGV) that provides enhanced imaging of the choroidal circulation. This newly assembled system was used to study a consecutive series of 129 patients with exudative age-related macular degeneration (AMD), and ill-defined or occult choroidal neovascularization (CNV). Overall, 39% of the patients in this study with occult CNV could be reclassified as having well-delineated or so-called classic CNV by virtue of the additional findings provided by ICGV. In this series, ICGV was particularly useful in identifying occult CNV in eyes with a large, serous pigment epithelial detachment (PED) and in eyes with recurrent CNV after previous laser photocoagulation treatment. Some of these patients were selected for laser photocoagulation of the abnormal choroidal vessels in order to evaluate the feasibility of this form of treatment on the basis of combined clinical, fluorescein angiographic, and ICGV findings. The results of this study suggest that ICGV is an important adjunct in the evaluation, classification, and laser treatment of patients with occult CNV secondary to AMD.

Indocyanine green angiography-guided photodynamic therapy for treatment of chronic central serous chorioretinopathy: a pilot study. 2003.

BACKGROUND: Most patients with central serous chorioretinopathy (CSC) have spontaneous resolution of exudative macular detachments and a good visual prognosis. Patients with CSC have a primary choroidal hyperpermeability problem evident as multifocal areas of hyperpermeability during indocyanine green (ICG) angiography. A small percentage of patients develop chronic or progressive disease with widespread decompensation of the retinal pigment epithelium and severe vision loss. There is no known treatment for this variant of the disorder. PURPOSE: To study ICG-guided photodynamic therapy (PDT) with verteporfin as a potential treatment for patients with chronic CSC. METHODS: Twenty eyes of 15 patients were studied with fluorescein angiography, optical coherence tomography, and ICG angiography to diagnose the maculopathy, monitor the detachments, and localize the choroidal hyperpermeability of the disorder. PDT with ICG guidance was applied to areas of choroidal hyperpermeability, and the patients were observed to determine the anatomic and functional outcomes. RESULTS: Photodynamic therapy guided by ICG was associated with complete resolution of exudative macular detachments in 12 patients and incomplete resolution in the remaining eight eyes. The vision improved in six eyes and remained unchanged in 14 eyes during a mean follow-up of 6.8 months. Six weeks after treatment, the mean visual acuity improved by 0.55 lines, an amount that was marginally significant. There was a significant inverse correlation between the baseline visual acuity and the amount of improvement in acuity at 6 weeks. No patient had any treatment-related side effects. CONCLUSIONS: Indocyanine green angiography-guided PDT with verteporfin seems to aid in the resolution of exudative detachments in patients with chronic CSC. This treatment was associated with a rapid reduction in subretinal fluid and improvement in visual acuity. Although the follow-up time and number of patients in this pilot study were limited, the encouraging results and lack of complications suggest that further study is indicated.

Indocyanine green angiography: a perspective on use in the clinical setting.

PURPOSE: To review the history of indocyanine green (ICG) angiography and to present a personal perspective on its use in the clinical setting today. DESIGN: Perspective with literature review and opinions based on personal experience. METHODS: To acquire views from international retinal physicians experienced with the technique on uses in their facilities and to compare them to the author's personal standards. RESULTS: The author and contributing retinal physicians had surprisingly similar views for most, but not all, applications for ICG angiography use in the clinical setting. CONCLUSIONS: ICG angiography is recommended for a few highly selective chorioretinal disorders, including certain forms of neovascularization in age-related macular degeneration, other neovascular maculopathies, chronic central serous chorioretinopathy, choroidal hemangiomas, and posterior uveitis.