Ocular manifestations of cancer.

Cancer may affect the eye and orbit by a direct effect of metastatic neoplastic infiltration or compression or by circulating antibodies involving paraneoplastic retinal degeneration. Metastatic tumor to the uvea is the most common form of an intraocular malignant process. The choroid is the most common site for uveal metastasis; metastases to the ciliary body, iris, retina, optic disc, 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 but the systemic prognosis is poor. The visual paraneoplastic syndromes encompass several distinct clinical and pathologic entities including carcinoma-associated retinopathy, melanoma-associated retinopathy, and bilateral diffuse melanocytic uveal proliferation. The first affects photoreceptors, the second is thought to affect bipolar cell function, and the third targets the uveal tract. Identification of circulating antibodies against retinal proteins (recoverin, 23-kD retinal protein; 46-kD and 60-kD retinal proteins) serves to recognize the paraneoplastic nature of the patient's symptoms, which frequently develop before the cancer is diagnosed. No therapy exists to stop the inexorable progressive loss of vision. Metastasis to the eye and orbit and paraneoplastic disorders represent a very bad prognostic sign. Recognition of their visual symptoms and ocular findings should alert the ophthalmologist to the possibility of cancer and systemic evaluation should be pursued.