Methods and apparatus for improved visualization of choroidal blood flow and aberrant vascular structures in the eye using fluorescent dye angiography

A method for visualizing the choriocapillaris from the other blood vessels in the choroid in a sequence of ICG angiographic images comprising the steps of:

• injecting intravenously a fluorescent dye, the dye filling the choriocapillaris and the other blood vessels in the choroid;
• exciting the dye thereby causing a fluorescence to be emitted from the choriocapillaris and the other blood vessels in the choroid;
• taking a sequence of angiographic images of the emitted fluorescence;
• and
• subtracting an image from a succeeding image, pixel by pixel, thereby forming a resultant image, the resultant image showing fluorescence emitted from the choriocapillaris.

A method for improving the visualization of choroidal neovascularization (CNV) during an angiography comprising the steps of:

• injecting intravenously a fluorescent dye, the dye filling the vasculature of an eye;
• exciting the dye thereby causing a fluorescence to be emitted from the vasculature;
• suppressing fluorescence other than fluorescence from the CNV using a polarizing filter placed in a fundus camera;
• and
• taking an angiographic image of the fluorescence from the CNV.

A device for improving the visualization of choroidal neovascularization (CNV) comprising:

• a fundus camera;
• an excitation light source coupled to the fundus camera;
• a polarizing filter placed in front of the light source;
• a means for receiving images from the fundus camera;
• and
• an analyzing polarizer placed between the receiving means and the fundus camera.

A device for providing superimposed angiograms of an eye comprising:

• a fundus camera for taking angiographic images of the eye;
• an integrating sphere coupled to the fundus camera;
• two light sources, each light source connected to the integrating sphere by a fiber optic cable and operating at a different wavelength to excite a first dye and a second dye causing a different fluorescence to be emitted from each dye;
• a means for receiving the angiographic images of the eye from the fundus camera;
• and
• a filter means between the fundus camera and the receiving means, the filter means containing at least two filters, a first filter to pass the fluorescence from the first dye and a second filter to pass the fluorescence from the second dye;
• wherein by alternating the first and second filters in synchrony with the firing of the light sources and the receiving means different angiograms are taken, the angiograms being superimposed thereby.

A method for providing superimposed angiograms comprising the steps of:

• injecting a first dye followed by a second dye thereby having two dyes present simultaneously;
• exciting the two dyes alternately with a first light source and a second light source, each light source having a different wavelength thereby alternately producing two different fluorescences;
• and
• recording the alternately produced fluorescences to provide superimposable angiograms.