Evaluation of Fixational Behavior throughout Life

Background: To quantify development of gaze stability throughout life during short and long fixational tasks using eye tracking technology. Methods: Two hundred and fifty-nine participants aged between 5 months and 77 years were recruited along the study. All participants underwent a complete ophthalmological assessment. Fixational behavior during long and short fixational tasks was analyzed using a DIVE (Device for an Integral Visual Examination), a digital test assisted with eye tracking technology. The participants were divided into ten groups according to their age. Group 1, 0–2 years; group 2, 2–5 years; group 3, 5–10 years; group 4, 10–20 years; group 5, 20–30 years; group 6, 30–40 years; group 7, 40–50 years; group 8, 50–60 years; group 9, 60–70 years; and group 10, over 70 years. Results: Gaze stability, assessed by logBCEA (log-transformed bivariate contour ellipse area), improved with age from 5 months to 30 years (1.27 vs. 0.57 deg2 for long fixational task, 0.73 vs. −0.04 deg2 for short fixational task), while fixations tend to be longer (1.95 vs. 2.80 msec for long fixational tasks and 0.80 vs. 1.71 msec for short fixational tasks). All fixational outcomes worsened progressively from the fifth decade of life. Log-transformed bivariate contour ellipse area (0.79, 0.83, 0.91, 1.42 deg2 for long fixational task and 0.01, 0.18, 0.28, 0.44 deg2 for short fixational task, for group 7, 8, 9, and 10 respectively). Stimuli features may influence oculomotor performance, with smaller stimuli providing prolonged fixations. Conclusions: Fixational behavior can be accurately assessed from 5 months of age using a DIVE. We report normative data of gaze stability and duration of fixations for every age group. Currently available technology may increase the accuracy of our visual assessments at any age.

Changes in Fixation Stability with Time during Binocular and Monocular Viewing in Maculopathy

The purpose of this study was to examine changes in fixation stability over time during binocular and monocular viewing in patients with age-related macular degeneration (AMD). Seventeen patients with AMD and 17 controls were enrolled. Using an EyeLink eyetracker (SR Research Ltd., Mississauga, Ontario, Canada), fixation stability was recorded binocularly and monocularly with each eye for a duration of 15 s while the fellow eye was covered. Fixation stability was analyzed over 3 s intervals for each condition using a 68% bivariate contour ellipse area. Fixation stability did not change with time during binocular viewing for both groups, both monocular conditions for the control group, and monocular viewing with the better eye for the AMD group. However, during monocular viewing with the worse eye, the test of within-subject contrasts showed linear improvement in fixation stability with time (p = 0.016). In conclusion, in patients with AMD, monocular fixational control with the worse eye is poor, but improves with time.

Eye Movements in Patients with Glaucoma When Viewing Images of Everyday Scenes

This study tests the hypothesis that patients with bilateral glaucoma exhibit different eye movements compared to normally-sighted people when viewing computer displayed photographs of everyday scenes. Thirty glaucomatous patients and 30 age-related controls with normal vision viewed images on a computer monitor whilst eye movements were simultaneously recorded using an eye tracking system. The patients demonstrated a significant reduction in the average number of saccades compared to controls (; mean reduction of 7% (95% confidence interval (CI): 3–11%)). There was no difference in average saccade amplitude between groups but there was between-person variability in patients. The average elliptical region scanned by the patients by a bivariate contour ellipse area (BCEA) analysis, was more restricted compared to controls (; mean reduction of 23% (95% (CI): 11–35%)). A novel analysis mapping areas of interest in the images indicated a weak association between severity of functional deficit and a tendency to not view regions typically viewed by the controls. In conclusion, some eye movements in some patients with bilateral glaucomatous defects differ from normal-sighted people of a similar age when viewing images of everyday scenes, providing evidence for a potential new window for looking into the functional consequences of the disease.