Abstract
Abstract: :
Purpose: To investigate central electroretinal function, using multifocal electroretinography, in patients on long-term chloroquine and hydroxychloroquine treatment. Methods: Nine patients receiving chloroquine (585 g. mean cumulative dose) and 14 patients receiving hydroxychloroquine (595 g. mean cumulative dose) had mERGs recorded from 61 regions in the central 45 degrees. Six patients had either fundoscopic evidence of retinopathy or visual field defects, and 2 patients had color vision anomalies. Mean response density and implicit time of the first order kernel were evaluated for the P1 component in five concentric rings (R1 - R5) extending to 22 degrees from the fovea. Results: For chloroquine treated patients, with increasing cumulative dose/kg body weight, P1 amplitude was significantly decreased in the foveal ring (R1, p<0.01) and paracentral rings (R3, p<0.04; R4, p<0.01 and R5, p<0.006). For hydroxychloroquine treated patients, P1 amplitude was significantly decreased in the parafoveal rings (R2, p<0.002; R3, p<0.008; R4, p<0.05). P1 implicit time was unaffected by cumulative dosage/kg body weight for rings R1 to R5 for patients on chloroquine or hydroxychloroquine treatment. Conclusions: Multifocal ERG detects retinal toxicity in clinically symptomatic and asymptomatic patients on long-term chloroquine and hydroxychlorine therapy. The mERG may emerge to the best method for early detection and follow up of eyes with suspected toxicity.
Keywords: electroretinography: clinical • drug toxicity/drug effects