Purpose: Fixation control is essential for valid automated perimetry. Current methods of fixation control during visual field testing include intermittent test tasks or video supervision by an examiner. We have developed a video based digital eye tracking system to measure gaze eccentricities during perimetry. Methods: During automated permit try gaze analysis was performed every 30 seconds using an eye tracking system based on digitalized video frames. The gaze eccentricities measured were compared to fixation constants calculated on the basis of test tasks. Results: The calculated fixation constants approached 90-100 %. Eye tracking (accuracy below 1 degree, reproducibility of 0.3 degrees) revealed an average gaze deviation of 4 ± 2.5 degrees horizontally and vertically. Extreme gaze deviations up to 18 degrees could be detected in the intervalls between stimulus presentation. Conclusions: Frequent measurements of gaze deviation reveal, that fixation control using perimetric test tasks may grossly underestimate the amount of incorrect fixation during visual field testing. Video based eye tracking can more accurately monitor the fixation during stimulus presentation, thus improving the quality of automated perimetry without prolonged test duration.
|Original language||English (US)|
|Journal||Investigative Ophthalmology and Visual Science|
|State||Published - Feb 15 1996|
ASJC Scopus subject areas
- Sensory Systems
- Cellular and Molecular Neuroscience