May 2004
Volume 45, Issue 13
ARVO Annual Meeting Abstract  |   May 2004
Validated Electrophysiological Measures of Visual Function in Legal Blindness
Author Affiliations & Notes
  • D. Mladenovich
    Ophthalmology, Johns Hopkins University, Baltimore, MD
  • A. Bittner
    Ophthalmology, Johns Hopkins University, Baltimore, MD
  • G. Dagnelie
    Ophthalmology, Johns Hopkins University, Baltimore, MD
  • Footnotes
    Commercial Relationships  D. Mladenovich, None; A. Bittner, None; G. Dagnelie, None.
  • Footnotes
    Support  FFB AMD Center Grant
Investigative Ophthalmology & Visual Science May 2004, Vol.45, 5441. doi:
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      D. Mladenovich, A. Bittner, G. Dagnelie; Validated Electrophysiological Measures of Visual Function in Legal Blindness . Invest. Ophthalmol. Vis. Sci. 2004;45(13):5441.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract: : Purpose:In our study, ERG, flash/flicker VEP (FVEP) and pattern reversal VEP (PVEP) tests were evaluated for within– and between–session reliability. These tests objectively monitor vision in legally blind subjects, whose vision cannot be precisely assessed by standard clinical outcome measures. The tests would be critical to detect small visual changes in future treatment trials. Methods:We have previously shown (Giger–Mateeva et al., ARVO 1999; Eshraghi et al., ARVO 2002) that ERG and FVEP phase information is reliable in most legally blind retinitis pigmentosa (RP) and ARMD (MD) subjects. In this study, we continued ERG and FVEP evaluation by adding the PVEP, increasing sample size, and including other eye diseases, resulting in 60 legally blind subjects and 10 normally sighted controls. Subjects were grouped according to pathology type: RP, MD, optic nerve (ON) or other retinal (OR) disease. RP and MD subjects were divided into sub–groups on the basis of remaining vision. Ganzfeld ERGs and FVEPs (single flash and flicker) and PVEPs were recorded multiple times and across sessions in order to determine reproducibility. Standard LKC UTAS 2000 system was used for VEPs and ERGs. The stimuli for PVEP were 6.3, 12.5, 25, 50 and 100 arcmin checkerboards (2 rev/sec and 100% contrast), displayed on a monitor. VEP flash rates were 10, 16, 20, and 31 Hz. ERG flicker rates were 20, 26, 31, and 37 Hz. Results:We confirm previous findings of reproducibility and reliability of ERG/FVEP responses in a larger sample size of RP and MD subjects. Response phases are reproducible for 1st and/or 2nd harmonic at each frequency. We further confirm that ERG and FVEP can be reliably measured in subjects with other retinal diseases. Preliminary PVEP results are reliable in some ON and OR subjects, most RP and MD subjects, and all controls. Ability to record a reliable P100 was strongly correlated with subject’s visual acuity. Conclusions:ERG and FVEP measures are reliable in most patients with severe vision loss, providing objective monitoring of visual function over time. These measures lend themselves to use across study centers, allowing direct comparison of treatment results among investigative teams and methods. PVEP results correlate with subject’s VA, but further analysis of reliability is needed.

Keywords: electrophysiology: clinical • low vision • clinical (human) or epidemiologic studies: systems/equipment/techniques 

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