Electroretinography.

<p>Mixed (cones and rods) photoreceptor b-wave amplitudes (microvolts) to a light stimulus in dark-adapted wild type (diamonds on dashed line) and MPS IIIB (squares on solid line) mice at ages 4 to 40 weeks demonstrating reduced response in MPS IIIB mice, that is statistically significant from 16 weeks onward. Cone response b-wave amplitudes after light adaptation is depicted for wild type (open diamond/dashed line) and MPS IIIB (open square/solid line) at the same ages and shows no difference in cone response.