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Updated: Apr 25, 2026
Multifocal Electroretinograms
Published on: December 4, 2011
Test-retest variability of multifocal electroretinography in normal volunteers and short-term variability in
1Charlotte Eye, Ear, Nose and Throat Associates, 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.
