Hemangiomas can grow within the blood vessel layer beneath the retina called the choroid. If they are located in the macula (center of vision) or they leak fluid which causes a retinal detachment or cystic changes in the retina, these changes can affect vision. Many choroidal hemangiomas never grow or leak fluid and may be observed without treatment. Choroidal hemangiomas are not cancers and never metastasize.
Fluorescein angiography is used by eye-care specialists to perform studies of the blood vessels in the eye. A vegetable dye called fluorescein is injected into the arm and travels to blood vessels inside the eye. If a tumor is present, it is possible to detect specific characteristics of its circulation which can help differentiate between it and other types of tumor. Choroidal hemangiomas have a unique pattern of circulation where the large blood vessels produce a "coarse vascular pattern."
Ultrasound can also be used to examine the inside of the eye. Choroidal hemangiomas are made up of relatively large and well-formed blood vessels. Each one of those blood vessels can reflect sound waves producing characteristically intense reflections from within the tumor.
Most circumscribed choroidal hemangiomas can be photographed and followed for evidence of growth or leakage prior to treatment. If they are documented to be growing into the center of vision or are causing a retinal detachment or angle-closure glaucoma, they can be treated in an effort to preserve vision.
Scatter laser photocoagulation has been used to decrease the amount of fluid leaking out of choroidal hemangiomas. Unfortunately most patients have recurrent problems (retinal detachment, cystoid retinal degeneration) after this treatment and suffer loss of vision.
More recently, relatively low doses of external beam irradiation have been used to treat leaking choroidal hemangiomas. Though these reports have been limited case series, this approach is promising in that radiation treats the entire tumor.