Purpose:
In this study we compare visual gaze behavior of glaucoma subspecialists with ophthalmology trainees during optic disc and retinal nerve fiber layer (RNFL) diagnostic examination for glaucoma.
Methods:
7 glaucoma subspecialists and 23 ophthalmology trainees participated in the project. Participants were shown 8 glaucomatous optic disc images with varied morphology. Eye movements during examination of optic disc photographs were tracked using a Tobii Eyetracker®. For each disc image graders were asked to assign a presumptive diagnosis for probability of glaucoma. There was no time restriction.
Results:
Overall, trainees spent more time looking at disc images than glaucoma subspecialists (mean 27.1 and 17.7 seconds, respectively, P<0.01), had no systematic pattern of gaze behavior and gaze behavior was unaltered by disc morphology or topographical cues of pathology. Experienced viewers demonstrated more systematic and ordered gaze behavior patterns and spent longer time observing areas with the greatest likelihood of pathology (superior and inferior poles of the optic nerve head and adjacent RNFL) compared to trainees. For discs with focal pathology, the proportion of total time spent examining definite areas of pathology was on average 27.7% for glaucoma subspecialists compared with 12.2% for trainees (P<0.05). Furthermore, experts adapted their viewing habit according to disc morphology.
Conclusions:
Glaucoma subspecialists adopt systematic gaze behavior when examining the optic nerve and RNFL, whereas trainees do not. It remains to be elucidated whether incorporating systematic viewing behavior of the optic disc and RNFL into teaching programs for trainees may expedite their acquisition of accurate and efficient glaucoma diagnosis skills.
Keywords: optic disc • visual search • eye movements: recording techniques