Cancer-Associated Retinopathy

Acute or subacute loss of visual acuity caused by circulating antibodies formed against the retinal proteins in the presence of systemic cancer is called cancer-associated retinopathy or carcinoma-associated retinopathy (CAR). It is described under the broad spectrum of autoimmune retinopathy (AIR) diseases. Autoimmune retinopathy can be paraneoplastic (pAIR) and nonparaneoplastic (npAIR).  Sawyer et al first described visual loss along with retinal degeneration in patients suffering from lung carcinoma in 1976. The term paraneoplastic retinopathy (PR) was coined by Klingele et al to describe autoimmune retinopathy associated with a distant neoplasm. They described PR as "a nonmetastatic remote effect of carcinoma and is characterized by rapid visual deterioration accompanied by narrow arterioles seen on ophthalmoscopic examination and an extinguished electroretinogram." In AIR, autoantibodies against retinal proteins are found in the serum of patients without a known malignancy, whereas, in PR, retinal antibodies are seen in the presence of an underlying malignancy.  CAR is a rare type of retinal paraneoplastic retinopathy. Paraneoplastic syndrome is defined as "rare clinical syndromes due to the systemic effects of tumors; they are unrelated to tumor size, invasiveness or metastases." CAR is characterized by sudden and progressive vision loss. Other entities included in the pAIR visual syndromes are melanoma-associated retinopathy (MAR), paraneoplastic optic neuropathy (PON), and bilateral diffuse uveal melanocytic proliferation (BDUMP).  Often, the loss of visual acuity from CAR can occur even before diagnosing cancer. It has been reported that the diagnosis of CAR (confirmed by the presence of antiretinal antibodies in the sera) precedes the diagnosis of cancer in up to 50% of patients. Management options for CAR include systemic steroids, intravenous immunoglobulin, and various monoclonal antibodies.