Figure 2.

Mean binocular summation across different luminance and VA conditions determined with three different approaches. Mean values and SEM of mean BiS for both luminance conditions (photopic and scotopic) and both VA types (cVA and hVA) [logMAR] are given for each group of calculations. BiS are calculated as the difference of binocular LogMAR and monocular LogMAR (A) For the better eye of each day; (B) for the better eye of both days; (C) for the mean across both days); approach B is less prone to misestimations (see text). Binocular improvement is given in logMAR, left, and as the corresponding binocular summation ratio (BSR), right. Note the inverted axis for the logMAR values so that binocular inhibition is shown at the bottom and good summation is at the top. There were no significant main effects of VA type and of luminance on BiS. The horizontal line indicates the established binocular improvement in literature, 40%.