Abstract
Purpose: :
Fundus and autofluorescence patterns of hydroxychloroquine or chloroquine retinopathy often reveal two zones of parafoveal retinal changes giving the classic bull’s eye maculopathy. We intend to compare parafoveal retinal thickness and inner segment/outer segment layer changes in patients taking hydroxychloroquine or chloroquine with and without maculopathy to age-matched controls.
Methods: :
Subject eyes were divided into four groups. Group I, 2 eyes (one patient) with bulls eye maculopathy; Group II, 4 eyes ( 2 patients) with only mfERG changes of toxicity, Group III, 16 eyes (8 patients) with exposure but no signs of toxicity, and Group IV, 8 eyes ( 4 patients) that were normal. SD-OCT was performed and retinal thickness was measured 0.5mm and 1mm from the center fovea. Temporal and nasal measurements were averaged to obtain mean retinal thickness.
Results: :
Mean retinal thickness 1mm from the fovea in eyes with bull’s eye maculopathy was significantly thinner when compared to controls. (234µm vs 347µm, p<.04). Similarly, eyes with only mfERG changes and no fundus abnormalities also showed retinal thinning 1mm from the fovea center when compared to controls. (325µm vs 348µm, p<.006). No significant changes in retinal thickness were observed in patients taking these medications with no signs of toxicity when compared to controls (p<0.2). Mean retinal thickness 0.5mm from foveal center did not differ significantly between any of our groups when compared to controls. Finally, loss of the IS/OS layer with preservation of the retinal pigment epithelium (RPE) and retinal structures was observed 0.5mm from the foveal center in eyes with maculopathy. In these eyes, loss of the IS/OS layer, RPE and outer retinal structures was observed 1mm from the foveal center.
Conclusions: :
We found that significant retinal thinning occurred 1mm from the foveal center in patients with early hydroxychloroquine or chloroquine toxicity and no signs of maculopathy, as well as in patients with signs of maculopathy. The retina exhibited no change 0.5mm from foveal center in eyes without maculopathy. Retinal structural changes were observed only in cases of maculopathy. Measuring retinal thickness 1mm from the foveal center in patients receiving these medications may help screen for early toxicity.
Keywords: drug toxicity/drug effects • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • macula/fovea