At iThemba Labs, we are constructing a patient positioning system for proton therapy. This system will use stereo vision techniques to accurately position the patient relative to the beam line. To do this, we need to be sure that the vision system is functioning correctly. In addition to various procedural checks, we implement a variety of software tests to try and detect errors in the vision s...

background: to determine the sensitivity, specificity, positive predictive value (ppv), and negative predictive value (npv) of the national vision screening program for 7 yr old children in iran. methods: in this cross-sectional study, eight cities in iran were selected through multistage cluster sampling. selected cities were sari, birjand, ardabil, mashhad, bandar abbas, dezful, yazd, and ara...

Dentists must be skilled when using dental mirrors. Working with mirrors requires spatial perception, bimanual coordination, perceptual learning and fine motor skills. Many studies have attempted to determine the predictors of manual skills among pre-clinical students, but consensus has yet to be reached. We hypothesized that valid and reliable occupational therapy test performance regarding in...

Accurately encoding the duration and temporal order of events is essential for survival and important to everyday activities, from holding conversations to driving in fast-flowing traffic. Although there is a growing body of evidence that the timing of brief events (< 1 s) is encoded by modality-specific mechanisms, it is not clear how such mechanisms register event duration. One approach gaini...

PURPOSE To explore the impact of spherical aberration (SA) on contrast sensitivity using an adaptive optics vision simulator to determine the optimal amount of SA to include in customized corrections of wavefront aberrations. SETTING Laboratorio de Optica, Universidad de Murcia, Murcia, Spain, and AMO Groningen BV, Groningen, The Netherlands. METHODS An adaptive optics vision simulator cons...

Food marketing environments of Black American consumers are heavily affected by ethnically-targeted marketing of sugar sweetened beverages, fast foods, and other products that may contribute to caloric overconsumption. This qualitative study assessed Black consumers' responses to targeted marketing. Black adults (2 mixed gender groups; total n = 30) and youth (2 gender specific groups; total n ...

PURPOSE A masked investigation of the relation between performance on various vision tests and reading was conducted with 90 kindergartners (mean age 5.73 years) and 91 first graders (mean age 6.76 years) from a middle class, suburban, elementary school near Cleveland, Ohio. METHODS Vision testing included the Modified Clinical Technique (MCT), +/- 2.00 D flipper lenses with red/green suppres...

The synoptophore was used to measure torsional interocular disparity. This, in turn, was used to compute how much the angle between the Listing's plane (LP) of the two eyes changes as a function of the vergence angle. The ratio of these two angles was defined as G. We measured G in normals and in patients suffering from intermittent horizontal strabismus. Consistent with previous search-coil ex...

During smooth pursuit eye movement performance often an illusory motion of background objects is perceived. This so called Filehne illusion has been quantified and explored by Mack and Herman [Q. J.exp. Psychol. 25, 71-84 (1973); Vision Res. 18, 55-62 (1978)]. According to them two independent factors contribute to the Filehne illusion: (1) a subject relative factor, viz. the underregistration ...

PURPOSE To assess the role of distance stereoacuity using the System Chart SC-1600 Pola (SC) to evaluate intermittent exotropia (IXT). METHODS Stereoacuity testing was performed in 28 children with IXT and 25 age-matched control subjects using the SC test, the distance Randot stereotest for distance, and the Titmus stereotest for near stereoacuity. Ocular alignment control was defined using t...