PURPOSE: With computer usage becoming almost universal in the contemporary workplace, the reported prevalence of computer vision syndrome (CVS) is increasing. However, the precise physiological mechanism underlying CVS remains unclear. While abnormal accommodation and vergence responses have been cited as being responsible for this condition, there is little objective evidence to support this c...

Eye movement research in reading has traditionally been associated with the investigation of visual processing and language comprehension (see, for example: (Kliegl, Nuthmann & Engbert, 2006, Liversedge, White, Findlay & Rayner, 2006b, Rayner, 1998)). Central to the description (and prediction) of eye movement behaviour during reading are saccades and fixations, which are traditionally extracte...

It has been claimed that, when a word is presented in isolation, recognition is affected by the precise location at which the word is fixated. However, this putative role for fixation location has yet to be reconciled with the finding from reading research that fixations made by each eye are frequently misaligned and so more than one location in a word is often fixated simultaneously. The accur...

Most people strongly prefer to use back-and-forth eye movements in order to discriminate 3-dimensional distances among targets that are widely separated from each other in direction. This viewing strategy permits sequential stereopsis: a comparison between the foveally-seen pre-saccadic disparity of one target with post-saccadic disparity of the other. This note describes a simple and qualitati...

We investigated the dynamics of accommodative and pupillary responses to random-dot stereograms presented in crossed and uncrossed disparity in six visually normal young adult subjects (mean age=25.8±3.1 years). Accommodation and pupil measures were monitored monocularly with a custom built photorefraction system while subjects fixated at the center of a random-dot stereogram. On each trial, th...

There has been a long-standing debate about the mechanisms underlying the perception of stereoscopic depth and the computation of the relative disparities that it relies on. Relative disparities between visual objects could be computed in two ways: (a) using the difference in the object's absolute disparities (Hypothesis 1) or (b) using relative disparities based on the differences in the monoc...

Stereoanomaly is the failure to see differences in depth when the viewer is presented with stimuli having different magnitudes of stereoscopic disparity. In the absence of eye movements, everyone suffers from stereoanomaly for extremely large disparities. Typically, such disparities are seen at the same depth as monocular stimuli. However, about 30%, of the population exhibit some form of stere...

Reading requires three-dimensional motor control: saccades bring the eyes from left to right, fixating word after word; and oblique saccades bring the eyes to the next line of the text. The angle of vergence of the two optic axes should be adjusted to the depth of the book or screen and--most importantly--should be maintained in a sustained manner during saccades and fixations. Maintenance of v...

A maximum a posterior probability zero disparity filter (MAP ZDF) ensures coordinated stereo fixation upon an arbitrarily moving, rotating, re-configuring hand, performing marker-less pixel-wise segmentation of the hand. Active stereo fixation permits real-time foveal hand tracking and segmentation over a large visual workspace, allowing investigation of unrestricted natural human gesturing. Ha...