Ocular Immunology Lab
The Ocular Immunology Laboratory at Casey Eye Institute offers retinal autoantibody tests for cancer-associated retinopathy (CAR), melanoma-associated retinopathy (MAR), autoimmune retinopathy and optic neuropathy. The lab is directed by Grazyna Adamus, Ph.D, Professor of Ophthalmology.
Cancer-Associated Retinopathy (CAR Syndrome)
CAR syndrome is a progressive subacute loss of vision associated with circulating autoantibodies against retinal proteins in the presence of systemic tumor growth. The most common malignancies related to CAR are carcinomas. These include small cell carcinoma of the lung, non-small cell carcinoma, and endometrial, ovarian, cervical, breast, prostate and colon carcinomas. The effects of cancer on the visual system, which can include complete loss of vision, consist of progressive blurred vision, photosensitivity, night blindness, impaired color vision, central or ring scotomas and constriction of visual fields. The electroretinogram (ERG) shows marked reduction or complete loss of rod and cone-mediated responses. Symptoms of CAR may develop before cancer is diagnosed or before the recurrence of cancer is recognized. The most common circulating autoantibodies found in patients are antibodies against recoverin (23-kDa) and α-enolase (46-kDa). Because visual symptoms may occur before cancer is diagnosed, screening for anti-retinal antibodies, especially against recoverin, can help to diagnose cancer.
Melanoma-Associated Retinopathy (MAR Syndrome)
Night blindness associated with a cutaneous malignant melanoma is distinct from CAR. In MAR, patients have acute onset of night blindness months to years after diagnosis of metastatic cutaneous melanoma. Characteristics of MAR include a rapid onset of night blindness, a constant sensation of shimmering or pulsating light and a selective reduction in the amplitude of both rod and cone ERG b-waves. Photoreceptor function is intact, but signal transmission between photoreceptors and second-order interneurons of the retina is defective. Antibodies reacting with the bipolar cells have been detected in the serum of MAR patients. Recently, autoantibodies with other specificities have also been found in serum from patients with MAR.
Autoimmune Retinopathy (AR)
Autoimmune retinopathy is the term for an acquired immunologically mediated retinal degeneration in association with serum anti-retinal autoantibodies. Visual symptoms resemble CAR or MAR but without tumor. In about 60% of patients who have onset of CAR-like or MAR-like visual symptoms, no neoplasm can be found on extensive evaluation. Paraneoplastic patients are usually older than patients with AR at the onset of visual symptoms.