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

Abstract

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.

Spontaneous involution of a large retinal arterial macroaneurysm

“…Because this angiographic finding is typical of retinal macroaneurysms (Schneider et al 1997), we diagnosed this mass lesion as a large retinal macroaneurysm. ICG angiography, with its absorption and emission peak in the near-infrared spectrum, allows observation of the lesion through hemorrhage (Flower & Hochheimer 1973;Hayashi & DeLaey 1985;Bischoff & Flower 1985). This ability is not possible with fluorescein angiography, which uses blue or green light in the shorter wavelengths.…”

“…The ICG angiographic sequence also was observed continuously on a videoscreen, which showed a pulsation of the macroaneurysm. In addition, because ICG is highly protein-bound (Flower & Hochheimer 1973;Hayashi & DeLaey 1985;Bischoff & Flower 1985), the dye leaks very slowly into the lumen of the macroaneurysm. This feature enables a detailed examination of the anatomical relationship between the retinal artery and the lumen of the macroaneurysm.…”

A review of therapies for diabetic macular oedema and rationale for combination therapy

“…129 These results would support the concept that CEC and REC behave differently under hyperglycaemia, and may explain, at least in part, some of the clinical differences observed in the frequencies/prevalences of DR and choroidopathy. [6][7][8][9] Western blotting indicated that claudin-5 protein expression was also higher in RECs, whereas JAM-A and C and VE-Cadherin levels were similar. 110 High-glucose conditions (equivalent to hyperglycaemia) significantly increased the permeability in both REC and CEC monolayers, although the increase was higher for RECs.…”

“…4,5 Diabetic choroidopathy is a less well-studied entity, and is thought to occur in the advanced stages of diabetic eye disease. [6][7][8][9] As such, the retinal and choroidal vascular beds seem to be affected differently by diabetes. Diabetes and hyperglycaemia have obvious effects on intraocular vascular endothelial cell (EC) permeability, adhesion to leukocytes, as well as angiogenesis.…”

“…The contributions of the choroidal vasculature to the clinical disease of DR are less well understood, but again will be largely contributed to by the choroidal EC (CEC) alterations. [6][7][8][9] It is known that retinal vascular leakage in DMO is contributed to by vascular endothelial growth factor (VEGF) upregulation as well as non-VEGFdependent inflammatory pathways, so that chronic subclinical inflammation is important in the pathogenesis of DR. [18][19][20][21][22][23][24][25][26][27][28] An early event in the pathogenesis of diabetic vasculopathy is leukocyte adherence to retinal vascular endothelium, resulting in EC death, vascular leakage, and capillary closure 18 (Figure 2).…”