Haiyan Zheng1, Menglu Shen1, Xianghang He1, Rong Cui1, Luis Andres Lesmes2, Zhong-Lin Lu3,4, Fang Hou1. 1. School of Ophthalmology & Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China. 2. Adaptive Sensory Technology, Inc, San Diego, CA, USA. 3. Division of Arts and Sciences, and NYU-ECNU Institute of Cognitive Neuroscience, NYU Shanghai, Shanghai, China. 4. Center for Neural Science and Department of Psychology, New York University, New York, NY, USA.
Abstract
PURPOSE: The contrast sensitivity function (CSF) is measured traditionally with grating stimuli. Recently, we introduced a new set of digit stimuli to improve the efficiency of CSF tests for people unfamiliar with the Latin alphabet. Given the significant differences between grating and digit stimuli, we conducted this study to evaluate whether the estimated CSFs from the digit test are equivalent to those from the grating test. METHODS: The CSFs of five young (with Psi) and five older (with quick CSF [qCSF]) participants were measured with a two-alternative forced choice (2AFC) grating orientation identification task and a 10-digit identification task. The CSFs obtained from the two tasks were compared. RESULTS: The estimated CSFs from the two tasks matched well after controlling for stimulus types and performance levels. The root mean square error (RMSE) between the CSFs from the two tasks was 0.093 ± 0.029 (300 trials) and 0.131 ± 0.016 (100 trials) log10 units for young and older observers, respectively. To reach the same standard deviation (0.1 log10 units), the digit CSF test required fewer trials/less time than the classic grating CSF for young (60 vs. 90 trials) and older (15 vs. 21 trials) observers. The complicated behavioral responses of the observer in the 10-AFC digit identification task can be accounted by a model that consists of digit similarity and one single parameter of sensory noise (χ2[99] = 3.42, P = 0.999). CONCLUSIONS: The estimated CSFs from the digit test highly matched those obtained from the grating test; however, the digit test is much more efficient. TRANSLATIONAL RELEVANCE: The digit CSF test provides a compatible assessment of the CSF as the traditional grating CSF test with more efficiency. Copyright 2019 The Authors.
PURPOSE: The contrast sensitivity function (CSF) is measured traditionally with grating stimuli. Recently, we introduced a new set of digit stimuli to improve the efficiency of CSF tests for people unfamiliar with the Latin alphabet. Given the significant differences between grating and digit stimuli, we conducted this study to evaluate whether the estimated CSFs from the digit test are equivalent to those from the grating test. METHODS: The CSFs of five young (with Psi) and five older (with quick CSF [qCSF]) participants were measured with a two-alternative forced choice (2AFC) grating orientation identification task and a 10-digit identification task. The CSFs obtained from the two tasks were compared. RESULTS: The estimated CSFs from the two tasks matched well after controlling for stimulus types and performance levels. The root mean square error (RMSE) between the CSFs from the two tasks was 0.093 ± 0.029 (300 trials) and 0.131 ± 0.016 (100 trials) log10 units for young and older observers, respectively. To reach the same standard deviation (0.1 log10 units), the digit CSF test required fewer trials/less time than the classic grating CSF for young (60 vs. 90 trials) and older (15 vs. 21 trials) observers. The complicated behavioral responses of the observer in the 10-AFC digit identification task can be accounted by a model that consists of digit similarity and one single parameter of sensory noise (χ2[99] = 3.42, P = 0.999). CONCLUSIONS: The estimated CSFs from the digit test highly matched those obtained from the grating test; however, the digit test is much more efficient. TRANSLATIONAL RELEVANCE: The digit CSF test provides a compatible assessment of the CSF as the traditional grating CSF test with more efficiency. Copyright 2019 The Authors.