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G. L. Trick, T. Levey; Multifocal ERG Abnormalities in Hydroxychloroquine Treated Patients. Invest. Ophthalmol. Vis. Sci. 2008;49(13):5018. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
The multifocal ERG (mfERG) can detect visual dysfunction in patients on hydroxychloroquine. This retrospective study was designed to determine whether the mfERG responses within specific topographic regions reflect hydroxychloroquine damage and to evaluate which mfERG parameters are best used to detect hydroxychloroquine induced functional deficits.
Multifocal ERG results from a consecutive series 19 patients (36 eyes) referred for evaluation of hydroxychloroquine toxicity were compared to results from 16 visually normal individuals (27 eyes). For each patient the clinical diagnosis, cumulative dose, duration of treatment, visual acuity and visual field sensitivity, as well as the mfERG amplitudes and latencies, were analyzed. The mfERGs were recorded using the VERIS Science 5.05. The N1 and P1 amplitudes for a central response (average of the central 7 hexagons), a peripheral response (average of the peripheral 96 hexagons) and a full field response were measured. For both N1 and P1 the ratios of the central to the peripheral responses also were computed.
Patients on hydroxychloroquine therapy exhibited statistically significant differences relative to the control for each of the N1 and P1 amplitude measures. Significant mfERG abnormalities were detected in 11 (30.6%) eyes of 8 (42.1%) patients receiving hydroxychloroquine therapy. These abnormalities were most frequently detected (19.4% of eyes, 26.3% of patients) using the P1 central to peripheral ratio (P1c/P1p). For the patients receiving hydroxychloroquine therapy significant correlations between P1c/P1p and both visual acuity and visual field sensitivity were observed. No significant correlation with cumulative dose was found.
Significant mfERG abnormalities were detected in over 40% of patients on hydroxychloroquine therapy. However, no single response measure detected abnormalities in more than 26.3% of patients. P1c/P1p most frequently detected abnormalities, and was correlated with visual function as measured by both visual acuity and visual field. Therefore, P1c/P1p may be the optimal single measure of mfERG abnormalities in patients on hydroxychloroquine therapy.
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