Electrophysiological and SD-OCT findings in patients receiving chloroquine therapy in relation to cumulative dosage and duration of treatment

Doc Ophthalmol. 2020 Aug;141(1):1-14. doi: 10.1007/s10633-019-09744-0. Epub 2020 Jan 11.


Purpose: Assessment of multifocal ERG (mfERG) changes in patients treated with chloroquine and their correlation with morphological abnormalities, detected by spectral-domain optical coherence tomography in relation to cumulative dosage.

Methods: Data from 37 eyes of 20 patients were retrospectively collected, and one randomly selected eye per patient was considered for statistical analysis. Eyes were divided into three groups according to mfERG and visual acuity findings: normal, early and advanced maculopathy. Functional measures of the first three mfERG rings were compared with retinal thickness measures of the corresponding OCT ETDRS circles. Data on cumulative dose and duration of therapy were also evaluated.

Results: The mean mfERG values progressively decreased according to the stage of the disease. In particular in the early maculopathy group, amplitudes were significantly reduced in all the three central rings. The mean ring ratio R1/R2 was abnormal only in the early maculopathy group. OCT thickness measures were significantly lower in all the three ETDRS circles in the advanced maculopathy group, and in the paracentral circle in the early maculopathy group. Considering all the eyes, there was a statistically significant correlation between functional and morphological values (p < 0.001). High chloroquine cumulative dosages were always associated with retinal toxic effects, whereas lower cumulative dosages generated different levels of toxicity.

Conclusions: This study shows a strong association between mfERG ring values and the corresponding OCT thickness measures; however, mfERG may enhance early detection of functional changes in patients treated with chloroquine, especially in ambiguous cases. At low chloroquine cumulative dosages, different subjects might have different susceptibilities to the drug.

Keywords: Chloroquine; Cumulative dosage; Maculopathy; Multifocal ERG; Optical coherence tomography; Toxicity.

MeSH terms

  • Adult
  • Aged
  • Antirheumatic Agents / adverse effects*
  • Arthritis / drug therapy
  • Arthritis, Rheumatoid / drug therapy
  • Chloroquine / adverse effects*
  • Duration of Therapy
  • Electroretinography / drug effects*
  • Female
  • Humans
  • Lupus Erythematosus, Systemic / drug therapy
  • Male
  • Middle Aged
  • Retina / diagnostic imaging
  • Retina / drug effects*
  • Retina / physiopathology
  • Retinal Diseases / chemically induced*
  • Retinal Diseases / diagnostic imaging
  • Retinal Diseases / physiopathology
  • Retrospective Studies
  • Tomography, Optical Coherence*
  • Visual Acuity / physiology
  • Young Adult


  • Antirheumatic Agents
  • Chloroquine