Purchase this article with an account.
A. M. Horwood, P. Riddell; Oculomotor Responses of Expert vs. Naïve Observers to Full and Impoverished Stimuli. Invest. Ophthalmol. Vis. Sci. 2008;49(13):1794.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Previous studies of vergence and accommodation have shown that infants and patient groups perform less well than adults. This could result from either a developmental change or a naïve/expert effect since the adult studies often use optometry students and staff as participants, potentially expert observers. This study explicitly tested naïve vs. expert adult participants.
A remote haploscopic off-axis videorefractor measured simultaneous accommodation and vergence (in dioptres and metre angles) to a detailed picture stimulus at 4 positions between 0.3m and 2m. Blur, disparity and looming cues were removed selectively by using a DOG patch, remote occlusion, and scaled targets respectively. Participants were tested with all combinations of cues (8 conditions). 10 undergraduates naïve to vision experiments were matched by age, refractive error, heterophoria, and fusion range with 10 orthoptics or optometry undergraduates ("experts") aware that accommodation and convergence were being studied. Instruction set was identical and minimal.
Mean stimulus/response slopes were higher in the expert group for vergence (p=0.001). Except for the proximity-only target, mean accommodation slope was also higher in the experts. Larger variance in the accommodation responses (particularly in the "experts") meant that the difference between groups did not reach significance in this small sample. 73% of vergence responses and 67% of the accommodation response slopes were steeper in the experts. While no participant over-converged by more than 10% for the target, many of the expert group over-accommodated.
We suggest that knowledge of the theory of vergence and accommodation may enhance responses in comparison to the general population. Differences between many reports of adult values and developmental and clinical literature may reflect expert / naïve effects as well as developmental change.
This PDF is available to Subscribers Only