37 research outputs found
Impaired saccadic eye movement in primary open-angle glaucoma
PURPOSE: Our study aimed at investigating the extent to which saccadic eye movements are disrupted in patients with primary open-angle glaucoma (POAG). This approach followed upon the discovery of differences in the eye-movement behavior of POAG patients during the exploration of complex visual scenes. METHODS: The eye movements of 8 POAG patients and 4 healthy age-matched controls were recorded. Four of the patients had documented visual field scotoma, and 4 had no identifiable scotoma on visual field testing. The eye movements were monitored as the observers watched static and kinetic targets. The gain, latency, and velocity-peak latency of the saccades recorded were then analyzed. RESULTS: In POAG patients, with abnormal visual fields, watching a static target, the saccades were delayed and their accuracy was reduced, compared with those of normal observers. In POAG patients, with normal and abnormal visual fields, watching a kinetic target, a task involving precise motion analysis, the latency and accuracy of the saccades were impaired, compared with those of normal observers. CONCLUSIONS: Our findings suggest that POAG alters saccade programming and execution particularly in the case of moving targets
Papilloedema and MRI enhancement of the prechiasmal optic nerve at the acute stage of Leber hereditary optic neuropathy
The authors report a case of one patient from a family carrying the homoplasmic Leber hereditary optic neuropathy (LHON) G11778A mitochondrial DNA mutation with papilloedema 9 months prior to the acute stage of LHON and still present at the onset of visual loss. During the vision loss, the MRI demonstrated a T2 hyperintensity and an enhancement of the prechiasmal left optic nerve, suggesting the existence of an inflammatory mechanism. A retrospective review of the chart of two others members of the same family, with bilateral optic disc oedema at onset of the vision loss, suggests that the relationship of papilloedema and acute phase of LHON may not be just a coincidence, at least in this family. The visual loss related to LHON could have been triggered in the setting of the chronic papilloedema, associated with the intracranial hypertension
Recommended from our members
Eye movements and reading in glaucoma: observations on patients with advanced visual field loss
Purpose To investigate the relationship between reading speed and eye movements in patients with advanced glaucomatous visual field (VF) defects and age-similar visually healthy people. Methods Eighteen patients with advanced bilateral VF defects (mean age: 71, standard deviation [SD]: 7 years) and 39
controls (mean age: 67, SD: 8 years) had reading speed measured using short passages of text on a computer set-up incorporating eye tracking. Scanpaths were plotted and analysed from these experiments to derive measures of âperceptual spanâ (total number of letters read per number of saccades) and âtext saturationâ (the distance between the first and last fixation on lines of text). Another eye movement measure, termed âsaccadic frequencyâ (total number of saccades made to read a single word), was derived from a separate lexical decision task, where words were presented in isolation. Results Significant linear association was demonstrated between perceptual span and reading speed in patients (R2=0.42) and controls (R2=0.56). Linear association between saccadic frequency during the LDT and reading speed was also found in patients (R2=0.42), but not in controls (R2=0.02). Patients also exhibited greater average text saturation than controls (P=0.004). Conclusion Some, but not all, patients with advanced VF defects read slower than controls using short text passages. Differences in eye movement behaviour may partly account for this variability in patients. These patients were shown to saturate lines of text more during reading, which may explain previously-reported difficulties with sustained reading
Pupil dilation does not predict subsequent stability in perceptual rivalry
International audienc