Simultaneous indocyanine green and fluorescein angiography.

PURPOSE: To facilitate the interpretation of the choroidal dye filling sequence, the use of simultaneous indocyanine green (ICG) and fluorescein angiography was evaluated. METHODS: A single-wavelength scanning laser ophthalmoscope (SLO) was modified to a two-wavelength system, permitting the simultaneous recording of ICG and fluorescein angiography. This method has been used in 340 cases. About two thirds of the patients had well-defined or occult choroidal neovascularization (CNV) in age-related macular degeneration (AMD). RESULTS: Simultaneous ICG and fluorescein angiography is feasible with a two-wavelength SLO and provides images of good quality. Two corresponding ICG and fluorescein angiography pictures can be presented as one combined red-green picture. CONCLUSION: This method has three advantages: (1) it allows a precise comparison of the transit of both dyes through both circulations, and there are no differences in the injected bolus nor in the actual blood pressure; (2) the important features of the ICG angiograms are fully aligned with the critical retinal vascular landmarks provided by the fluorescein images; and (3) it is very time efficient--with a single injection and one photographic session, immediate results are obtained.

Angiographic study of the vortex vein circulation.

This paper reports the possibility of measuring the filling pattern of a vortex vein in vivo using the method of choroidal angiography with indocyanine green dye (ICG), as described by Flower. We studied eight eyes of six healthy volunteers in order to establish the normal filling time of the vortex veins. In the temporal vortex veins studied the dye was first seen about 1.2 s after initial filling of the corresponding radial choroidal arteries. The vortex veins were maximally fluorescent within 5 s.

Ten years experience with choroidal angiography using indocyanine green dye: a new routine examination or an epilogue?

The choroidal circulation can be studied by an angiographic technique which utilizes near-infrared light wavelengths and a biocompatible dye, indocyanine green (CardiogreenR). Near-infrared light is less absorbed than visible light by the pigment epithelium and the macular xanthophyll, and indocyanine green (ICG) dye doesn't leak from the choriocapillaris as sodium fluorescein dye typically does. Due to the high rate of choroidal blood flow, a fundus camera adapted with special filters and a continuous light source was used in order to make angiograms at the rate of 10 per second. Our experience at the Wilmer Institute and the Eye Clinic at St. Gallen includes 180 choroidal angiograms of normal volunteers and approximately 500 choroidal angiograms of patients with several fundus diseases, mainly senile macular degeneration, diabetic retinopathy and choroidal tumors. Although many of our results are preliminary, we present them to demonstrate the potential applications of this method in ophthalmology. Some factors which may have inhibited an extensive propagation of clinical choroidal angiography in the past are also discussed.

Scanning electron microscopic studies of the hyaloid vascular system in newborn mice exposed to O2 and CO2.

It has been suggested that the tunica vasculosa lentis of newborn mice undergoes vasoproliferation after oxygen exposure and might be used as an experimental model for intraocular neovascularization. A scanning electron microscopic technique which provides visualization of the entire hyaloid vascular system was used to study its response in mice exposed to various gas mixtures (70% O2/30% N2, 10% CO2/90% air, 10% CO2/70% O2/20% N2). Marked differences were found between hyaloid regression in gas exposed mice compared to air control mice, but no evidence of neovascularization was found in any group. The data support the possibility that changes in the hyaloid may be the consequence of the hydrostatic coupling which exists between this atrophic, possibly flow-resistant vasculature and the developing retinal vasculature whose blood flow characteristics are significantly altered by exposure to CO2 and O2.