[Ocular manifestations of cancer]

Cancer may affect the eye and orbit as a direct result of metastatic neoplastic infiltration, compression, or circulating antibodies involving paraneoplastic retinal degeneration. A metastatic tumor to the uvea is the most common form of an intraocular metastatic process. The choroid is the most common site for uveal metastasis; metastases to the ciliary body, iris, retina, optic disk, and vitreous are rare. Approximately one-third of patients have no history of primary cancer at the time of ocular diagnosis. Breast and lung carcinomas for women and lung and gastrointestinal carcinomas for men most commonly metastasize to the eye and orbit. The short-term prognosis for vision is usually good after an individualized therapeutic approach (chemotherapy, hormonal therapy, external beam radiotherapy, or plaque radiotherapy), but the systemic prognosis is poor. The visual paraneoplastic syndromes encompass several distinct clinical and pathological entities including carcinoma-associated retinopathy (CAR), melanoma-associated retinopathy (MAR), and bilateral diffuse melanocytic uveal proliferation (BDUMP). The CAR syndrome affects photoreceptors, MAR is thought to affect bipolar cell function, and BDUMP targets the uveal tract. Identification of circulating antibodies against retinal proteins (recovering, 23-kDa retinal protein; 46-kDa and 60-kDa retinal proteins) serves to recognize the paraneoplastic nature of the patient's symptoms, which frequently develop before the cancer is diagnosed. Anecdotal therapeutic responses are described after systemic steroids, immunoglobulin injection, and plasmapheresis. Recognition of their visual symptoms and ocular findings should alert the ophthalmologist to the possibility of cancer and systemic evaluation should be pursued.