The purpose of this study is to learn how blood flows to tumors in patients treated with I-125 plaque brachytherapy for uveal melanoma.

Despite having excellent local tumor control rates, uveal melanoma remains a life-threatening cancer, and even eye-sparing therapy with radiation treatment often leads to significant loss of vision. Major challenges to providing care to patients with uveal melanoma include the inability to accurately predict long-term vision in an eye treated with radiation, due to a poor understanding of the nature of radiation retinopathy and optic neuropathy. Optical coherence tomography (OCT) is a commonly used ophthalmic imaging modality that provides precise, real-time data in vivo in a non-invasive manner. Our research group has recently developed two novel functional OCT technologies: (1) Doppler OCT to quantitatively measure total retinal flow and (2) OCT angiography technology to map optic nerve head, retinal, and choroidal blood flow with unprecedented accuracy. The investigators believe this technology can be utilized to improve understanding of radiation-induced vascular changes in the optic nerve and retina that cause vision loss in patients treated with radiation, as well as provide a tool to monitor tumor response to treatment.

In this study, the investigators intend to utilize these novel functional OCT technologies to describe the changes over time in optic nerve head and retinal blood flow after I-125 radiation therapy, and to evaluate the relationship between changes in flow and decreased vision. The investigators will also study the association between changes in flow and the total radiation doses received by the optic nerve head and macula, which varies based upon tumor location and size.

Inclusion Criteria:

• Adults age 18 and older with uveal melanomas involving the ciliary body and/or the choroid undergoing I-125 plaque brachytherapy.

Exclusion Criteria:

• Inability to give informed consent.
• Inability to maintain stable fixation for OCT imaging
• Significant renal disease, defined as a history of chronic renal failure requiring dialysis or kidney transplant
• A condition that, in the opinion of the investigator, would preclude participation in the study (e.g., unstable medical status including blood pressure, cardiovascular disease, and glycemic control).
• Blood pressure > 180/110 (systolic above 180 OR diastolic above 110). If blood pressure is brought below 180/110 by anti-hypertensive treatment, subject can become eligible.
• Women who are pregnant or lactating at the time of enrollment due to unknown safety of fluorescein angiography. Women that become pregnant during the course of the study may remain enrolled; however, flurorescein and ICG angiography will not be performed until they are no longer pregnant or nursing an infant.

This study will measure blood flow changes in 28 patients with uveal melanoma requiring radiation therapy.