Eye cancer-related glaucomas occur through a variety of mechanisms. They can be challenging to diagnose and are often refractory to treatment. The literature reveals the variety of ways eye cancers cause glaucoma. Mechanisms include direct invasion, infiltration, or seeding of the aqueous outflow structures as well as indirect processes, such as compressive angle closure and anterior segment neovascularization. This review describes established, evolving, and new diagnostic techniques (e.g., high-frequency ultrasound and aspiration biopsy techniques). Treatment options typically depend upon the tumor type (primary or secondary), its location, and mechanism of glaucoma. However, they include standard pharmacologic, laser, incisional, and radiotherapeutic approaches. We hope this review leads to early detection and optimum treatment of eye cancer-related glaucomas. Clearly, prompt diagnosis and management of eye cancer-related glaucoma offers an opportunity to both preserve vision and the patient's life.