This study is testing a new treatment called belzupacap sarotalocan (bel-sar) against a sham control (a fake treatment) for people with eye problems known as primary indeterminate lesions (IL) or small choroidal melanoma (CM). The treatment is done using a special tool called a suprachoroidal (SC) microinjector that puts the medicine in a specific part of the eye. A laser then helps to activate the medicine. If you join the study, you will be randomly assigned to get either the real treatment or the sham. You must have been diagnosed with IL or CM and have no signs of cancer spreading. You should not have had treatment for IL or CM before, except for a specific type called PDT. You cannot join if you have other eye infections or are allergic to the study medicine or laser.

• The study checks how safe and effective bel-sar is.
• Participants must have specific eye conditions but no spreading cancer.
• Participants should not have certain allergies or other eye problems.