2. an antigen present on human erythrocytes that is exposed by treatment with neuraminidase or contact with certain bacteria. see CD a. T-dependent antigen one that requires the presence of helper T cells to stimulate antibody production by B cells; most antigens are T-dependent.. an antigen present on human erythrocytes that is exposed by treatment with neuraminidase or contact with certain bacteria. see CD a. T-dependent antigen one that requires the presence of helper T cells to stimulate antibody production by B cells; most antigens are T-dependent.
Causes of retinal migraine. Retinal migraine is caused by the blood vessels to the eye suddenly narrowing (constricting), reducing the bloodflow to the eye. Afterwards the blood vessels relax, bloodflow resumes and sight returns. Usually there are no abnormalities within the eye and permanent damage to the eye is rare.
People with ocular migraines can have a variety of visual symptoms. You might see a small, enlarging blind spot (scotoma) in your central vision with bright, flashing or flickering lights (scintillations), or wavy or zig-zag lines surrounding the blind spot.