Reading performance in middle-aged adults with declines in accommodation

The present study investigated the effects of presbyopia on the reading ability of middle-aged adults in a Japanese reading context, using the rapid serial visual presentation paradigm. Japanese words, each consisting of three characters, were sequentially presented at the same location on a display screen. Participants were instructed to read the words aloud as accurately as possible, irrespective of their order within the sequence. Experiment 1 showed that the reading performance for the presbyopes was far worse for the near-viewing (35?cm) than for the far-viewing (70?cm) conditions when the words were presented at 0.4° in character size. Experiment 2 investigated in detail the effect of luminance contrast on reading at a viewing distance of 35?cm. The minimums of the exposure durations within which the participants could read the words above 89.9?% correct (minimum exposure duration) were 498?ms/word for the presbyopes and 134?ms/word for the nonpresbyopes, both of which values were obtained at 100?% contrast. The critical contrast??that is, the contrast that doubled the minimum exposure duration that had been obtained at 100?% contrast??was considerably higher for the presbyopes (39.2?%) than for the nonpresbyopes (16.4?%). However, the reading performance for the presbyopes was improved more than threefold when the contrast was increased to 100?% in both experiments. Thus, our results provide psychophysical evidence for the dependency of presbyopes?? reading on viewing distance and luminance contrast.     

Breaking Surface Feature Continuity of Previewed Mask Reinstates Object Substitution Masking12

Perception of a briefly presented target is impaired when a sparse surrounding mask (e.g., four-dot) persists after target offset compared to when the target and mask offset together (i.e., object substitution masking [OSM]). Previous studies have reported a mask preview effect in which OSM is largely attenuated by prior presentation of the mask. Here, we investigated how breaking object continuity of the previewed mask affects the mask preview effect. Introducing an abrupt surface color change of the previewed mask at target onset disrupted the beneficial effect of mask preview, that is, OSM was reinstated (Experiment 1). The masking induced by mask color change exhibited the same two characteristics as conventional OSM: target location specificity and non-necessity of voluntary attention to the mask (Experiment 2). These results suggest that a sudden change in surface color breaks object continuity of the previewed mask and causes the mask to be represented as a new one, which triggers OSM anew.