Reliability of the compensation comparison method for measuring retinal stray light studied using Monte-Carlo simulations

• Published in: Journal of biomedical optics Vol. 11; no. 5; p. 054010
• Main Authors: Coppens, Joris E, Franssen, Luuk, van den Berg, Thomas J T P
• Format: Journal Article
• Language: English
• Published: United States 01.09.2006
• Subjects: Computer Simulation; Humans; Light; Models, Biological; Models, Statistical; Monte Carlo Method; Psychometrics - methods; Refraction, Ocular - physiology; Refractometry - methods; Reproducibility of Results; Retina - anatomy & histology; Retina - physiology; Retinoscopy - methods; Scattering, Radiation; Sensitivity and Specificity; Vision Tests - methods
• ISSN: 1083-3668
• DOI: 10.1117/1.2357731

Recently the psychophysical compensation comparison method was developed for routine measurement of retinal stray light. The subject's responses to a series of two-alternative-forced-choice trials are analyzed using a maximum-likelihood (ML) approach assuming some fixed shape for the psychometric function (PF). This study evaluates the reliability of the method using Monte-Carlo simulations. Various sampling strategies were investigated, including the two-phase sampling strategy that is used in a commercially available instrument. Results are given for the effective dynamic range and measurement accuracy. The effect of a mismatch of the shape of the PF of an observer and the fixed shape used in the ML analysis was analyzed. Main outcomes are that the two-phase sampling scheme gives good precision (Standard deviation = 0.07 logarithmic units on average) for estimation of the stray light value. Bias is virtually zero. Furthermore, a reliability index was derived from the responses and found to be effective.