Assessing Visual Acuity in Mouse Models

The photopic optomotor response of mice was measured using the OptoMotry System (CerebralMechanics) at a background light of ≈70 cd/m² as previously described (Xiong et al., 2019 (link)). The contrast of the grates was set to be 100%, and temporal frequency was 1.5 Hz. The threshold of mouse visual acuity (i.e., maximal spatial frequency) was tested by an examiner without knowledge of the control vs. experimental groups. During each test, the direction of movement of the grates (i.e., clockwise or counterclockwise) was randomized, and the spatial frequency of each testing episode was determined by the software. Without knowing the spatial frequency of the moving grates, the examiner reported either ‘yes’ or ‘no’ to the system until the threshold of acuity was determined by the software. Optomotor tests were conducted on rd10 and Rho^-/- mice, but not with rd1 strain, which loses vision at a very early age, before any meaningful test could be performed.