Abstract

Visual acuity, a forced-choice psychophysical measure of visual spatial resolution, is the sine qua non of clinical visual impairment testing in ophthalmology and optometry patients with visual system disorders ranging from refractive error to retinal, optic nerve, or central visual system pathology. Visual acuity measures are standardized against a norm, but it is well known that visual acuity depends on a variety of stimulus parameters, including contrast and exposure duration. This paper asks if it is possible to estimate a single global visual state measure from visual acuity measures as a function of stimulus parameters that can represent the patient's overall visual health state with a single variable. Psychophysical theory (at the sensory level) and psychometric theory (at the decision level) are merged to identify the conditions that must be satisfied to derive a global visual state measure from parameterised visual acuity measures. A global visual state measurement model is developed and tested with forced-choice visual acuity measures from 116 subjects with no visual impairments and 560 subjects with uncorrected refractive error. The results are in agreement with the expectations of the model.

Details

Title
Merging Psychophysical and Psychometric Theory to Estimate Global Visual State Measures from Forced-Choices
Author
Massof, Robert W 1 ; Schmidt, Karen M 2 ; Laby, Daniel M 3 ; Kirschen, David 4 ; Meadows, David 5 

 Johns Hopkins University, USA 
 University of Virginia, USA 
 Harvard University, USA 
 University of California Los Angeles, USA 
 University of Florida, USA 
Publication year
2013
Publication date
Sep 2013
Publisher
IOP Publishing
ISSN
17426588
e-ISSN
17426596
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2577547839
Copyright
© 2013. This work is published under http://creativecommons.org/licenses/by/3.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.