Normal visual acuity in p27L-/L- mice using the optomotor response. (A) Known visual pathways interrogated by the optomotor response test. (B) Optomotor tracking response to moving gratings was measured using a virtual optomotor system. Spatial frequency thresholds that elicited an optomotor response between tamoxifen control and experimental animals during the peaks of Müller glial proliferation and GFAP upregulation, and during chronic GFAP expression (1.5, 6 and 16 weeks post-inactivation, respectively). A sine wave grating was drawn on a virtual cylinder projected on monitors and the cylinder was rotated to test each. The value for each animal represents the average of both eyes. Data are expressed as the mean ± SD.