ICG is an eye test that is used to detect blood vessel problems in the choroid. This test is important because some blood vessel conditions can lead to vision loss if not diagnosed and treated early. The procedure uses an injected harmless green dye called indocyanine green. The dye reflects infrared light that is picked up by a special camera. An ICG is different than a fluorescein angiography, a similar imaging test and is often used in conjunction with a fluorescein angiogram to define a particular problem in the macula.
ICG produces detailed pictures that can show leaking blood vessels, blocked blood vessels, or vascular abnormalities. The test is also used to determine if laser surgery is possible and to plan laser surgery. ICG can pinpoint a blood vessel leak and determine the exact location to be lasered. ICG is used for many conditions, including age-related macular degeneration, choroid tumors, retinal detachment, retinal hemorrhage, and choroidal neovascularization.
You will need to have someone else drive you home from the test because your vision will be blurred following the procedure. Your doctor may have you discontinue taking certain medications prior to the test. You should tell your doctor if you are hypersensitive to iodine, allergic to X-ray dye, or allergic to shellfish. You should tell your doctor if you are pregnant or have liver disease.
Your doctor will dilate your pupils with eye drops. Your face will be stabilized with a positioning device for the test.
Your doctor will use special cameras to take pictures. The dye will be injected into your vein. Your doctor will take a series of photographs as the dye moves through your blood vessels.
Your vision will be blurred for several hours after your test. Your urine will be darker than usual for a few days, as the dye leaves your system. In rare cases, some people may be hypersensitive or allergic to the dye. Because the reaction can occasionally be serious, you should call your doctor immediately if you experience symptoms. Symptoms may include nausea, vomiting, dry mouth, increased saliva production, a metallic taste in your mouth, feeling dizzy or faint, hives, sneezing, and increased heart rate.