Purchase this article with an account.
M. MacKeben, A. Gofen, D. C. Fletcher; SLO Analysis of Scanning Eye Movements in Patients With Central Field Loss. Invest. Ophthalmol. Vis. Sci. 2007;48(13):3550.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To study scanning eye movement (SEM) strategies in people with central scotomas who use a PRL in a "find-and-identify" paradigm.
SEMs were measured monocularly using a scanning laser ophthalmoscope (SLO). 15 subjects (Ss) with maculopathies (42 to 92 yrs of age) had to find and identify Landolt rings in the image scanned onto their retina by the SLO’s He-Ne laser. Target size was set at threshold, which was independently determined by an adaptive staircase method. Only successful trials were recorded. The time needed, number of saccades and their directions were analyzed.
Ss took between 1.65 and 9.2 seconds to identify the Landolt ring (median duration = 5.66 s). They made between 3 and 33 saccades to solve the task, equivalent to 1.75 - 4.1 saccades/s. This measure correlated with Ss age (r = 0.68). Performance (time needed) showed a moderate negative correlation with Ss age (r = - 0.64), but no significant correlation with visual acuity (r = 0.08). Features improving SEM efficiency were a low number of saccades per second (r= 0.69) and a predominance of horizontal SEMs. There was also a good correlation (r = 0.7) of performance with best achievable reading speed (MNread).
The findings of this study confirm our previous hypothesis (MacKeben et al., ARVO 2006) that the large differences between patients in performance trying to find and identify simple targets and the high correlation with reading speed are indeed based on features of scanning eye movements.
This PDF is available to Subscribers Only