Duffy and Wurtz [(1993) Vision Research, 33, 1481-1490] found an illusory shift in the position of the focus of expansion (FOE) of random dot patterns when planar motion was superimposed on expanding radial motion. Subjects indicated that this illusory shift was in the direction of the planar motion. This is the opposite direction to a true shift in the FOE that is perceived when the planar motion is vector summed with the expanding motion. We account for this illusion by suggesting that planar motion induces opposite motion on the expanding dots which after vector summation produces the illusory shift in the FOE. We use a matching technique with a method of adjustment to measure induced motion and perceived FOE in moving random dot patterns and present the results in support of our assertion.
BackgroundAdjuvant use of laser with systemic chemotherapy for treatment of retinoblastoma may reduce recurrence rates while also causing local side effects. Information is lacking on the effect of laser on visual outcomes.MethodsA retrospective review of two retinoblastoma centres in the United Kingdom was conducted. Patients were included if there was a macular tumour in at least one eye. Eyes that received chemotherapy alone were compared with eyes that received chemotherapy plus adjuvant laser.ResultsA total of 76 patients and 91 eyes were included in the study. Systemic chemotherapy alone was used in 71 eyes while chemotherapy plus laser was used in 20 eyes. Demographic characteristics of both groups were similar. Macular relapse rates were similar between groups: 22/71 (31%) eyes in chemotherapy group and 9/20 (45%) eyes in laser group (p=0.29). There was no increase in vitreous relapses in the laser group (2/20 eyes), compared with the chemotherapy group 10/71 eyes (p=0.99). Survival analysis demonstrated similar time to first relapse between groups. Final visual acuity was equal between groups with 6/15 or better present in 31.1% of eyes in the chemotherapy group and 37.5% of eyes in the laser group (p=0.76). Presence of tumour at the fovea was predictive of final visual acuity, regardless of treatment group.ConclusionAdjuvant laser in the treatment of retinoblastoma is safe and does not lead to increased rate of vitreous recurrence. Final visual acuity is determined by the presence of tumour at the fovea and not the use of laser.
Building on phenomenological studies of the body and feminist structural materialist film theory and practice, this article proposes that performed methods of direct-on-film animation shape novel choreographies and produce original filmic patterns and rhythms. The author draws a parallel between Foucault's disobedient 'non-normative' body and non-standardized interventions with film technology. The article analyses the innovative choreographies that arise from rotoscoping techniques, direct-on-film practices and expanded cinema performances. Focusing specifically on Free Radicals (Len Lye, 1958) and Reel Time (Annabel Nicolson, 1973), the author uses these analyses to shed light on her own performance of making films by moving in unusual ways, in time with technologies, and marking directly onto the film surface with the animated body. While engaging with structural materialist questions of film form, process and materials, this article departs from such modernist concerns to propose that the performance of filmmaking offers opportunities to explore the tenacity and vulnerability of particular bodies. The author suggests that performed filmmaking is equally about the traces of actions made on film and the unusual choreography that brings these marks into being.
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