PURPOSE: To evaluate the effect of operator and optical defocus on the variability of pattern electroretinogram optimized for glaucoma detection (PERGLA). METHODS: Two different operators obtained 2 PERGLA recordings each from 10 healthy participants (5 women, mean age 32.1+/-10.3 y). In addition, one of the operators obtained recordings in which corrective lenses of various diopters (+/-0.5, +/-1, +/-2, and +/-3) were used to generate optical defocus in both eyes. The effect of operator on PERGLA amplitude and phase variability was determined using a single nested variance components' analysis model and by using Bland-Altman plots. One-way analysis of variance (ANOVA) was used to determine the effect of optical defocus on amplitude and phase. RESULTS: Differences in measurements between operators accounted for approximately 26.6% and 18.2% of the total variance for amplitude and phase, respectively. Results were confirmed by the use of Bland-Altman plots. ANOVA identified a significant effect of defocus on mean amplitude (F=2.65, P=0.01), but not phase (F=1.02, P=0.42). CONCLUSIONS: Measurements obtained by different operators can result in significant differences in PERGLA amplitude. In addition, although optical defocus leads to a decrease in PERGLA amplitude by reducing visual acuity, this can be avoided by obtaining J1 or better vision before testing.
PURPOSE: To evaluate the effect of operator and optical defocus on the variability of pattern electroretinogram optimized for glaucoma detection (PERGLA). METHODS: Two different operators obtained 2 PERGLA recordings each from 10 healthy participants (5 women, mean age 32.1+/-10.3 y). In addition, one of the operators obtained recordings in which corrective lenses of various diopters (+/-0.5, +/-1, +/-2, and +/-3) were used to generate optical defocus in both eyes. The effect of operator on PERGLA amplitude and phase variability was determined using a single nested variance components' analysis model and by using Bland-Altman plots. One-way analysis of variance (ANOVA) was used to determine the effect of optical defocus on amplitude and phase. RESULTS: Differences in measurements between operators accounted for approximately 26.6% and 18.2% of the total variance for amplitude and phase, respectively. Results were confirmed by the use of Bland-Altman plots. ANOVA identified a significant effect of defocus on mean amplitude (F=2.65, P=0.01), but not phase (F=1.02, P=0.42). CONCLUSIONS: Measurements obtained by different operators can result in significant differences in PERGLA amplitude. In addition, although optical defocus leads to a decrease in PERGLA amplitude by reducing visual acuity, this can be avoided by obtaining J1 or better vision before testing.
Authors: Christopher Bowd; Ali Tafreshi; Gianmarco Vizzeri; Linda M Zangwill; Pamela A Sample; Robert N Weinreb Journal: J Glaucoma Date: 2009-08 Impact factor: 2.503
Authors: Lori M Ventura; Iuri Golubev; William Lee; Izuru Nose; Jean-Marie Parel; William J Feuer; Vittorio Porciatti Journal: J Glaucoma Date: 2013-03 Impact factor: 2.503
Authors: Ali Tafreshi; Lyne Racette; Robert N Weinreb; Pamela A Sample; Linda M Zangwill; Felipe A Medeiros; Christopher Bowd Journal: Am J Ophthalmol Date: 2010-03 Impact factor: 5.258