Visual field and multifocal electroretinography and their correlations in patients on hydroxychloroquine therapy

Purpose To evaluate the effects of hydroxychloroquine on visual field and multifocal electroretinography (mfERG) and their correlations in patients taking hydroxychloroquine. Methods This was a cross-sectional study in which patients on hydroxychloroquine therapy underwent automated 10-2 threshold static visual field examination and mfERG recordings. Non-parametric unadjusted and age-adjusted Spearman correlation coefficients rho were calculated between the cumulative dose of hydroxychloroquine and the visual field mean deviation (MD) and pattern standard deviation (PSD) values; and the mfERG response amplitudes and peak latencies. Correlation analysis was also performed between the visual field MD and PSD values and the mfERG response amplitudes and peak latencies. Results A total of 26 eyes in 13 patients were analyzed. The mean duration of hydroxychloroquine therapy was 4.9 years and the mean cumulative dose was 574 g. No significant correlation was found between the cumulative dose of hydroxychloroquine and the visual field MD and PSD values. There were significant correlations between the cumulative dose of hydroxychloroquine and mfERG N1 and P1 response amplitudes for the central rings (ring 1-3). The correlations between the dose of hydroxychloroquine and mfERG N1 and P1 response amplitudes were strongest for the paracentral ring 2 (rho =-0.63 and rho =-0.62, respectively, P = 0.001). Significant correlations were also found between the visual field MD values and mfERG response amplitudes of various ring eccentricities. Conclusions In patients on hydroxychloroquine, mfERG response amplitude correlated with both the 10-2 visual field MD values and with the cumulative dose of hydroxychloroquine used. The use of mfERG can provide objective measurement of retinal function in patients on hydroxychloroquine and may provide supplementary quantitative information to visual field findings.