Test-retest variability of multifocal electroretinography in normal volunteers and short-term variability in hydroxychloroquine users
David J Browning,1 Chong Lee2
1Charlotte Eye, Ear, Nose and Throat Associates, 2University of North Carolina – Charlotte, Charlotte, NC, USA
Purpose: To determine measurement variability of N1P1 amplitudes and the R1/R2 ratio in normal subjects and hydroxychloroquine users without retinopathy.
Design: Retrospective, observational study.
Subjects: Normal subjects (n=21) and 44 patients taking hydroxychloroquine (n=44) without retinopathy.
Methods: Multifocal electroretinography (mfERG) was performed twice in one session in the 21 normal subjects and twice within 1 year in the hydroxychloroquine users, during which time no clinical change in macular status occurred.
Main outcome measures: N1P1 amplitudes of rings R1–R5, the R1/R2 ratio, and coefficients of repeatability (COR) for these measurements.
Results: Values for N1P1 amplitudes in hydroxychloroquine users were reduced compared with normal subjects by the known effect of age, but R1/R2 was not affected by age. The COR for R1–R5 ranged from 43% to 52% for normal subjects and from 43% to 59% for hydroxychloroquine users; for R1/R2 the COR was 29% in normal subjects and 45% in hydroxychloroquine users.
Conclusion: mfERG measurements show high test-retest variability, limiting the ability of a single mfERG test to influence a decision to stop hydroxychloroquine; corroborative evidence with a different ancillary test is recommended in a suspicious case.
Keywords: multifocal electroretinography, hydroxychloroquine, test-retest variability
This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at https://www.dovepress.com/terms.php and incorporate the Creative Commons Attribution - Non Commercial (unported, v3.0) License. By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. For permission for commercial use of this work, please see paragraphs 4.2 and 5 of our Terms.Download Article [PDF] View Full Text [HTML][Machine readable]