Plaid slant and inclination thresholds can be predicted from components

We investigated whether stereoscopic slant and inclination thresholds for surfaces defined by two component plaids could be predicted from the interocular differences in their individual component gratings. Thresholds were measured for binocular images defined by single sinusoidal gratings and two component plaids. In both cases thresholds showed a marked dependence on component orientation. For absolute component orientations greater than 45 deg we found that inclination thresholds were smaller than slant thresholds. However, for absolute component orientations less than 45 deg, we found a reversal: slant thresholds were smaller than inclination thresholds. We considered three models that might account for these data. One assumed that thresholds stemmed from interocular position differences of corresponding image points. The other two assumed a combination of position, orientation and/or spatial-frequency differences. The best fits were obtained from those models that explicitly represented orientation differences. From the model combining orientation and spatial-frequency differences, we estimated the relative cue sensitivity to be 1.7:1, respectively. For plaids, we found that thresholds obtained from the individual components could be used to predict thresholds for plaids, even though an additional disparity cue from the contrast beat was available

Perception and representation of stereoscopic slant and curvature

SIGLEAvailable from British Library Document Supply Centre- DSC:D94148 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Common mechanisms for 2D tilt and 3D slant after-effects

By presenting oriented Gabor patches either monocularly or binocularly, we dissociated retinal orientation from perceived tilt and perceived slant. After adapting to binocular patches, with zero apparent tilt and non-zero slant, small tilt after-effects (TAEs) and large slant after-effects (SAE) were measured. Adapting to monocular patches with non-zero tilt and zero slant produced large TAEs and smaller SAEs. This pattern of results suggests that a common, low-level adaptation to monocular orientation is involved in slant and tilt after-effects. However, the incomplete transfer between slant and tilt makes it clear that higher-level adaptation is also involved, perhaps at the level of surface representation

Binocular inhibition in strabismic patients is associated with diminished quality of life

PURPOSE: This prospective study aims to characterize the relationship between binocular summation (BiS) and binocular inhibition (BI) on the quality of life (QoL) of adult and pediatric patients with strabismus. METHODS: A binocular summation score was measured using ETDRS and Sloan low contrast acuity (LCA) protocols at 2.5% and 1.25% contrast. Patients were categorized as having BiS (binocular visual acuity superior than better-eye visual acuity by 5 or more letters), BI (binocular visual acuity worse than better-eye visual acuity by 5 or more letters) or otherwise indeterminate (less than 5 letter difference between binocular visual acuity and monocular visual acuity of the better-eye). QoL was evaluated by the National-Eye-Institute-Visual-Functioning-Questionnaire-25 (NEI-VFQ-25), 20-item- Adult-Strabismus-Questionnaire (AS-20) and the Amblyopia-and-Strabismus-Questionnaire. RESULTS: There was no significant BiS or BI for high-contrast-ETDRS or 2.5% LCA tests. However, mean binocular summation score of −2.14±7.0 letters for 1.25% LCA demonstrated significant binocular inhibition (p=0.004) for this contrast level. Mean composite NEI-VFQ-25 score was significantly lower in subjects with BI on ETDRS (80±19 vs. 57±7 for subjects with BiS and BI, respectively, p=0.03), 2.5% LCA (81±14 vs. 66±16 for subjects with BiS and BI, respectively, p=0.01), and 1.25% LCA tests (91±9 vs. 72±14 for subjects with BiS and BI, respectively, p=0.005). After accounting for potential covariates, significant association persisted for BI demonstrated by 1.25% LCA (p=0.01). With BI demonstrable at 2.5%, AS-20 scores were also significantly lower (p=0.04). CONCLUSION: Strabismic patients with BI had significantly lower QoL scores than those who did not, even after accounting for potential covariates, and even in the absence of diplopia